Joint Seminar of the Analysis, Geometry and Topology Department

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Joint Seminar of Analysis, Geometry and Topology Department will be held on July 4, 2023 at 2:00 pm (UTC+3)  in Room 478 of IMI. A talk on: Independence Structures in Random Matrix Theory and Random Partitions  will be delivered by Yacine Barhoumi-Andréani, University of Bochum, Germany. Everybody is invited. Abstract.We consider two models of random objects: eigenvalues of random matrices and random integer partitions for two classical measures: the GUE and the Schur measure. We express the largest element of these sets as maxima of independent random variables. The method uses orthogonal polynomials on the real line in the random matrix case and on the unit circle in the second case. The distribution involved in the random matrix case uses the [...]

Mathematics Days in Sofia 2023

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The Institute of Mathematics and Informatics of the Bulgarian Academy of Sciences in collaboration with the Union of Bulgarian Mathematicians and the Faculty of Mathematics and Informatics of Sofia University organize the next issue of the international conference Mathematics Days in Sofia from July 10 to July 14, 2023. Please vist the conference website for more information: http://mds.math.bas.bg/

Tenth Anniversary International Conference “New Directions in Applications of Differential Equations in the Sciences”

Международен дом на учените „Фредерик Жолио-Кюри“, кк „Свети Константин и Елена“ Св. Св. Константин и Елена, Varna, Varna

The conference is the only conference in Bulgaria on differential equations and their applications, which takes place every year. Scientists from three continents gather at this forum with the aim of exchanging knowledge and new ideas related to both the theory and differential equations - particular and ordinary, as well as their application in real problems arising in biology, mathematical physics, financial mathematics, fractional analysis , the neurosciences, etc.

Mathematical Modelling and Numerical Analysis Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the seminar of the Department of Mathematical Modeling and Numerical Analysis will be held on July 17, 2023, Monday, at 2:00 pm in Room 503 of the Institute of Mathematics and Informatics. A public inaugural lecture on Biochemical reaction networks and applications in epidemiological modeling will be delivered by Assoc. Prof. Milen Borisov.  

Inaugural lecture by Assoc. Prof. Danila Cherkashin

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

On Friday, Kuly 21, 2023, at 2:00 pm (GMT+3) in the Conference Room of IMI-BAS, Assoc. Prof. Danila Cherkashin will deliver an inaugural lecture on: Gilbert—Steiner problem Abstract. Gilbert—Steiner problem lies in the class of mass transportation problem. Consider two finite atomic probablistic measures in the plane. The goal is to construct a network (which is an embedded forest) of the lowest price. The price functional is the some over the roads (the edges of the forest) of its capacity in the power a, which is between 0 and 1, mutiplied on the length. We give an introduction in the problem and prove that a solution do not contain branching point of degree 4. The lecture will be streamed via Zoom:  https://us02web.zoom.us/j/83111372029?pwd=MzE5WGRBMHkyQWVESC9rd2ZjVlVmQT09 .   [...]

Seminar of the Information Modeling Department

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the seminar of the Information Modeling Department will be held on June 25, 2023, at 2:00 pm, in Room 578 of IMI. The following talks will be delivered: 1. Public inaugural lecture by Assoc. Prof. Ivan Radoslavov Georgiev: An Optimization Model for Production Scheduling Taking into Account Preventive Maintenance in an Uncertainty-Based Manufacturing System 2. Lecture by Asen Toshev on: Influence of the Balkan haplogroups in Europe Abstract. Examining the haplogroups from Eupedia [1] we conclude that two haplogroups are characteristic of the Balkans: I2*/I2a and E1b1b.The main goal of this paper is through the Balkan haplogroups to investigate the Balkan influence on countries outside the Balkans, i.e."Balkan" connections with peoples outside the Balkans, possibly migrations from the Balkans to other European [...]

Workshop on Recent developments in Hodge theory

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

A workshop "Recent developments in Hodge theory" organized by the Institute of the Mathematical Sciences of the Americas (IMSA) and the International Center for Mathematical Sciences (ICMS-Sofia) will be held at IMI-BAS on August 9, 10 and 11. The program as well as titles and abstracts of the talks are available at: https://simons.icms.bg/event/recent-developments-in-hodge-theory/ PROGRAM The talks by Phillip Griffiths, Institute for Advanced Study, USA Ernesto Lupercio, Cinvestav-IPN, Mexico Vestislav Apostolov, Université du Québec à Montréal, Canada and Institute of Mathematics and Informatics, Sofia, Bulgaria Gueo Grantcharov,  Florida International University, USA are part of the  Consortium Distinguished Lecture Series.

International Conference “Generalized and Symplectic Geometry”

Dreams Sunny Beach Resort & Spa Sunny Beach, 8240 Burgas

From 14 to 18 August 2023, the International Conference Generalized and Symplectic Geometry will be held at Dreams Sunny Beach Resort & Spa. The event is jointly organized by the Institute for the Mathematical Sciences of the Americas (IMSA) at the University of Miami, and the International Centre for Mathematical Sciences (ICMS-Sofia) at the Institute of Mathematics and Informatics at the Bulgarian Academy of Sciences in Sofia. Details can be found at https://simons.icms.bg/event/generalized-and-symplectic-geometry/.

Mathematical Foundations of Informatics Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Mathematical Foundations of Informatics seminar will be held on August 22, 2023, at 4 p.m. in Room 503 of the Institute of Mathematics and Informatics. A talk on: Data Attribution: Scaling up and Applications to Defending Against Backdoor Attacks will be delivered by Kristian Georgiev, PhD student at MIT under the guidance of Aleksander Mądry. Abstract. The goal of data attribution is to trace model predictions back to training data. Despite a long line of work towards this goal, existing approaches to data attribution tend to force users to choose between computational tractability and efficacy. That is, computationally tractable methods can struggle with accurately attributing model predictions in non-convex settings (e.g., in the context of deep neural networks), while [...]

Workshop on Mathematical Perspectives on Immunobiology

Университетски център „Бачиново“ - Благоевград 42°01'59.6"N 23°07'46.6"E, Благоевград

The Workshop on Mathematical Perspectives on Immunobiology brings together researchers who do research on one of the most complex systems of the human organism: the immune system.

Didactical Modeling Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the seminar Didactical Modeling will be held on September 18, 2023, at 2:30 pm in Room 278 of IMI – BAS. A talk on: The problem of Apollonius solved fully, exhaustively, and practically will be delivered by Assoc. Prof. Boyko Bantchev.

Joint meeting of the Analysis, Geometry and Topology Seminar and the Algebra and Logic Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

A joint meeting of the Analysis, Geometry, and Topology Seminar and the Algebra and Logic Seminar will be held on September 26, 2023, at 2:00 pm in Room 478 of IMI - BAS. A talk on Burau Representation and Application to Reducibility and Exchangeability of Braids will be delivered by Alexander Stоimenov, Dongguk University, Republic of Korea. Abstract. I will give an introduction to the braid groups, closure operation, Markov theorem, and exchange move. Then I will introduce the Burau representation, and discuss its application to reducibiliy and exchangeability of braids.

Algebra and Logic Seminar

Zoom

The next meeting of the Algebra and Logic Seminar will be held online in Zoom on September 29, 2023 (Friday) at 1:00 pm (UTC+2). A talk on: Reset Controller Synthesis will be delivered by Naijun Zhan (Institute of Software Chinese Academy of Sciences (ISCAS), China). Abstract. Controller synthesis provides a Correct-by-construction mechanism to guarantee the correctness and reliability of hybrid systems (HS) by design. Depending on the types of controls, controllers can be classified into reset controllers, feedback controllers, and switching logic controllers. Reset controllers steer the behaviour of a HS to attain system objective through restricting its initial set and redefining the reset map associated with discrete jumps, which is less explored in the literature, although it is of theoretical and practical significance. In this [...]

Didactical Modeling Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the seminar Didactical Modeling will be held on October 9, 2023, at 2:30 pm in Room 278 of IMI – BAS. A talk on: Modelling in problems from two renewed competitions will be delivered by Boyanka Savova and Assoc. Prof. Ivaylo Kortezov.

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The first meeting of the ICMS Seminar for 2023/2024 will be held on October 10, 2023, at 2:00 pm in Room 403 of IMI - BAS. A talk on: About a generalisation of Sylvester’s law of inertia will be delivered by Stéphanie Cupit-Foutou (Ruhr Universitat, Bohum). https://icms.bg/about-a-generalisation-of-sylvesters-law-of-inertia-talk-by-stephanie-cupit-foutou/ Abstract. Sylvester’s law of inertia can be formulated in terms of group actions when considering real linear groups acting on real quadratic forms by base change. After reviewing this celebrated result from this perspective, I will give a generalisation of it in the setting of so-called spherical varieties (a class of complex varieties including flag varieties, toric varieties, symmetric spaces, etc.). This is a joint work with D. Timashev

Algebra and Logic Seminar

Zoom

The next meeting of the Algebra and Logic Seminar will be held in hybrid format (in Room 578 of IMI and online via Zoom) on October 13, 2023 (Friday) at 1:00 pm (UTC+3). A talk on: Emmy Noether’s Theorem on the Finite Generation of the Algebra of Invariants will be delivered by Marin Genov (Institute of Mathematics and Informatics, Bulgarian Academy of Sciences). Abstract. I will introduce Emmy Noether’s theorem on the finite generation of invariants and give two proofs of it. As an example, I will also calculate the algebra of invariants of the dihedral group of order 2n acting on C[x,y]. Link to the Zoom room: https://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 Algebra and Logic Department, IMI - BAS http://www.math.bas.bg/algebra/seminarAiL/ ============================== =====================

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: October 17, 2023, 2:00 pm Place: Room 403, IMI - BAS Speaker: Mikhail Shkolnikov, IMI-BAS Title: Tropical structures in sandpile model Abstract: The sandpile model is a cellular automaton that can be defined on any graph. Though it has appeared independently in a variety of contexts, it attracted tremendous attention from the wide scientific community when its instance on a large domain of the square lattice was put forward as the simplest rigorous example of self-organized criticality. Such phenomena, real-life examples of which are earthquakes, solar flares, or neuronal avalanches, could be vaguely described as being between order and chaos, demonstrating power laws without being finely tuned, and transcending the scale. Tropical geometry, on the other hand, is a field of pure mathematics [...]

Seminar of the Operations Research, Probability and Statistics Department

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the seminar of the Department of Operations Research, Probability and Statistics will be held on October 17th, 2023, at 2:00 p.m. (UTC+3). A talk on: On an Infinite-Time Horizon Linear-Quadratic Game with Constrained Control will be delivered by Boyan Stefanov. Abstract. A linear-quadratic game on an infinite horizon for continuous and discrete-time systems is studied when the controls of the minimizing player are constrained. Our approach is based on the approximation of this game by a suitable finite-time horizon game. First, the existence of a saddle point equilibrium is proved for the unconstrained case. Next, it is established that there exists a delta-neighborhood of the origin in the state space where the control constraints are not active. Using this neighborhood, the [...]

Algebra and Logic Seminar

Zoom

The next meeting of the Algebra and Logic Seminar will be held in hybrid format (in Room 578 of IMI and online via Zoom) on October 20, 2023 (Friday) at 1:00 pm (UTC+3). A talk on: Prime numbers and random walks in a square grid will be delivered by Alberto Fraile (Czech Technical University in Prague, Czech Republic). Joint work with Osame Kinouchi, Prashant Dwivedi, Roberto Martínez, Theophanes E. Raptis, and Daniel Fernández Abstract. One can argue that prime numbers present perplexing features, in a hybrid of local unpredictability and global regular behavior. It is this interplay between randomness and regularity that motivated searches for both local and global patterns that could potentially become signatures for certain underlying fundamental mathematical properties.In recent years, computer simulations [...]

Didactical Modeling Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the seminar Didactical Modeling will be held on October 23, 2023, at 2:30 pm in Room 278 of IMI – BAS. A talk on: On models of mathematics camps and research programs for students in Europe will be delivered by Miroslav Marinov.

Applied Mathematics Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Finite automata and neural networks for language modeling Speaker: Prof. Stoyan Mihov Date: October 25, 2023 Time: 3:00 pm Place: Room 503 of IMI - BAS Facebook page of the seminar: Семинар по Приложна математика

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: October 30, 2023, 2:00 pm Place: Room 403, IMI - BAS Speaker: Peter Dalakov, IMI-BAS Course title: Introduction to Projective Structures and Opers Abstract: A complex projective structure on a Riemann surface is determined by an atlas, whose transition functions are Moebius (fractional-linear) transformations. There are multiple   descriptions of these structures: as certain flat PGL_2-bundles, as Sturm-Liouville operators, as holomorphic connections on the (first) jet bundle of the dual of a theta-characteristic, etc. This mini-course is an introduction to the fundamentals of projective structures, accessible to students and non-specialists. We will also explore links to some classical geometric objects (such as quadratic differentials and Schwarzian derivatives), as well as some generalisations (G-opers) introduced by Beilinson and Drinfeld. https://icms.bg/introduction-to-projective-structures-and-opers/  

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: October 31, 2023, 2:00 pm Place: Room 403, IMI - BAS Speaker: Peter Dalakov, IMI-BAS Course title: Introduction to Projective Structures and Opers Abstract: A complex projective structure on a Riemann surface is determined by an atlas, whose transition functions are Moebius (fractional-linear) transformations. There are multiple   descriptions of these structures: as certain flat PGL_2-bundles, as Sturm-Liouville operators, as holomorphic connections on the (first) jet bundle of the dual of a theta-characteristic, etc. This mini-course is an introduction to the fundamentals of projective structures, accessible to students and non-specialists. We will also explore links to some classical geometric objects (such as quadratic differentials and Schwarzian derivatives), as well as some generalisations (G-opers) introduced by Beilinson and Drinfeld. https://icms.bg/introduction-to-projective-structures-and-opers/  

Mathematical Foundations of Informatics Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Mathematical Foundations of Informatics seminar will be held on October 31, 2023, at 4 p.m. in Room 578 of the Institute of Mathematics and Informatics. A talk on: On binary codes with distances d and d+2 will be delivered by Dr. Konstantin Vorobev, IMI - BAS. Abstract. In this work, we consider the problem of determining the exact value of A_2(n, {d, d+2}) defined as the maximal cardinality of a binary code of length n with two possible distances d and d+2 . We prove that for fixed even d and n big enough, an optimal code must be a constant-weight code of weight d/2+1 with possibly no more than one additional codeword of a [...]

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: November 2, 2023, 2:00 pm Place: Room 403, IMI - BAS Speaker: Peter Dalakov, IMI-BAS Course title: Introduction to Projective Structures and Opers Abstract: A complex projective structure on a Riemann surface is determined by an atlas, whose transition functions are Moebius (fractional-linear) transformations. There are multiple   descriptions of these structures: as certain flat PGL_2-bundles, as Sturm-Liouville operators, as holomorphic connections on the (first) jet bundle of the dual of a theta-characteristic, etc. This mini-course is an introduction to the fundamentals of projective structures, accessible to students and non-specialists. We will also explore links to some classical geometric objects (such as quadratic differentials and Schwarzian derivatives), as well as some generalisations (G-opers) introduced by Beilinson and Drinfeld. https://icms.bg/introduction-to-projective-structures-and-opers/  

Algebra and Logic Seminar

Zoom

The next meeting of the Algebra and Logic Seminar will be held online via Zoom on November 3, 2023 (Friday) at 1:00 pm (UTC+2). A talk on: A Reduction of Temporary Coalitions in Infinite Multiplayer Games will be delivered by Dimitar Guelev (IMI-BAS, Bulgaria). Abstract.We propose a transformation of Concurrent Game Models which enables the reduction of infinite multiplayer games where players can form temporary coalitions to games with no coalitions by extending moves to include the negotiation steps that lead to the formation of coalitions. We adopt conditional promises as the building blocks of negotiation. Temporary coalitions and their agendas arise as the logical consequences of mutual promises. The transformation enables the use of established solution concepts about games with no coalitions for [...]

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: November 6, 2023, 2:00 pm Place: Room 403, IMI - BAS Speaker: Peter Dalakov, IMI-BAS Course title: Introduction to Projective Structures and Opers Abstract: A complex projective structure on a Riemann surface is determined by an atlas, whose transition functions are Moebius (fractional-linear) transformations. There are multiple   descriptions of these structures: as certain flat PGL_2-bundles, as Sturm-Liouville operators, as holomorphic connections on the (first) jet bundle of the dual of a theta-characteristic, etc. This mini-course is an introduction to the fundamentals of projective structures, accessible to students and non-specialists. We will also explore links to some classical geometric objects (such as quadratic differentials and Schwarzian derivatives), as well as some generalisations (G-opers) introduced by Beilinson and Drinfeld. https://icms.bg/introduction-to-projective-structures-and-opers/  

Joint Seminar of the Analysis, Geometry and Topology Department

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Joint Seminar of Analysis, Geometry and Topology Department will be held on November 7, 2023 at 2:00 pm (UTC+2)  in Room 478 of IMI. A talk on: New and little known properties of the Fox and Fox-Wright functions  will be delivered by Dmitrii Karp, Holon Institute of Technology, Holon, Israel. Everybody is invited. Abstract.In the talk, I will introduce the functions H of Fox and W of Wright (its general case known as Fox-Wright function) and some motivation behind them. Then, I will discuss the extension of Gauss' expansion and summation formulas for the hypergeometric function to the case of general Fox-Wright function and Norlund's expansion for the Meijer's G function to the case of Fox's H function. I will [...]

National Seminar on Probability and Statistics

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the National Seminar on Probability and Statistics will be held on November 8, 2023, at 2:00 p.m. in Room 503 of the Institute of Mathematics and Informatics. A talk on: Hamiltonicity of randomly perturbed graphs will be delivered by Alberto Espuny Díaz (Postdoctoral researcher at Universität Heidelberg, Germany). Abstract. In parallel to the development of smoothed analysis of algorithms, the study of randomly perturbed graphs has thrived in the combinatorics community. The setup is the following: one considers a dense graph $H$ which fails to satisfy some increasing property and then sprinkles edges randomly until the property appears. A main goal in the area is to understand how many random edges are needed, and which graphs $H$ are "worst" for this [...]

National Seminar on Probability and Statistics

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the National Seminar on Probability and Statistics will be held on November 15, 2023, at 2:00 p.m. in Room 503 of the Institute of Mathematics and Informatics. A talk on: Anti-concentration of Rademacher sums and Tomaszewski's counterpart problem will be delivered by Julien Portier, University of Cambridge. Abstract

ICMS Geometry Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next session of the Geometry Seminar of ICMS will be held next Wednesday, November 8th, at 16:00, in room 403 and via Zoom. A talk on Tropicalizations II will be delivered by Mikhail Shkolnikov, IMI-BAS. Abstract: I will start by briefly recalling the two approaches to tropicalizing subvarieties of algebraic tori. We then transition to the compactified version, substituting the torus with a toric variety, and formalizing the concept of embedded tropical varieties together with a notion of their smoothness. Notably, not all such varieties can be realized as tropicalizations of classical varieties, and different embeddings of classical varieties yield combinatorially distinct tropicalizations, which we equate through so-called modifications. We will conclude by addressing the question of recovering information about classical varieties from [...]

Algebra and Logic Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Algebra and Logic Seminar will be held in hybrod format (in Room 578 of IMI - BAS and online via Zoom) on November 10, 2023 (Friday) at 1:00 pm (UTC+2). A talk on: Transfinite version of the Mittag-Leffler condition for the vanishing of the derived limit will be delivered by Mishel Carelli (Technion – Israel Institute of Technology, Israel). Abstract.We give a necessary and sufficient condition for an inverse sequence  S0 ← S1 ← . . . indexed by natural numbers to have lim¹S = 0. This condition can be treated as a transfinite version of the Mittag-Leffler condition. We consider inverse sequences in the category of abelian groups. We also show that the class of inverse sequences S [...]

Mathematical Foundations of Informatics Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Mathematical Foundations of Informatics seminar will be held on November 10, 2023, at 2 p.m. in Room 478 of the Institute of Mathematics and Informatics. A talk on: On induced C_4 -free graphs with high average degree will be delivered by Antonio Girao. Abstract. A long-standing conjecture of Thomassen from the 80's states that every graph with sufficiently high average degree contains a subgraph with high girth and still preserving large enough average degree. This conjecture has only been resolved in the early 2000's by Kühn and Osthus in the first non-trivial case i.e. they showed that for every k , there is f(k) such the every graph with average degree at least f(k) contains a subgraph which [...]

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: November 14, 2023, 2:00 pm Place: Room 403, IMI - BAS Speaker: Peter Dalakov, IMI-BAS Course title: Invariant theory, homogeneous projective varieties, and momentum maps Abstract: Let f:K\to U(V) be a unitary representation of a compact Lie group K with Lie algebra \mathfrak k . This series of talks will be devoted to some recent developments based on relations between the following three classical notions. The ring of K -invariant polynomials \mathbb C[V]^K is finitely generated by homogeneous elements, by a theorem of Hilbert, but the proof is notoriously nonconstructive. The degrees of a minimal set of generators are canonically determined by f , and will be the focus of the discussion. The K -equivariant momentum map \mu:\mathbb P(V)\to \mathfrak [...]

Applied Mathematics Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

How log-concavity fought lottery frauds in Florida and what it did after winning Speaker: Dmitri Karp Date: November 14, 2023 Time: 2:00 pm Place: Room 503 of IMI - BAS Abstract: In the talk I will first discuss the log-concavity in parameters of the normalized beta function (which represents the cumulative distribution function of beta distributed random variable) that has been used recently in an investigation of lottery frauds in Florida.  I will then present some related  properties of incomplete beta function and proceed to general log-concavity problems and their particular cases motivated by various problems in statistics, probability and analysis. Facebook page of the seminar: Семинар по Приложна математика

National Mathematics Colloquium

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

UNION OF BULGARIAN MATHEMATICIANS INSTITUTE OF MATHEMATICS AND INFORMATICS, BULGARIAN ACADEMY OF SCIENCES NATIONAL MATHEMATICS COLLOQUIUM The next meeting of the National Mathematics Colloquium will be held on November 14, 2023 (Tuesday) at 4:15 pm EET (UTC +2) in the Conference Room of IMI - BAS. A talk on: Arcs of High Divisibility and Their Applications to Coding Theory will be delivered by Prof. Ivan Landjev, Institute of Mathematics and Informatics, Bulgarian Academy of Sciences. Abstract Everybody is invited.  

ICMS Geometry Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next session of the Geometry Seminar of ICMS will be held on Wednesday, November 15th, at 16:00, in room 403 and via Zoom: Topics in non-archimedean analytic geometry (I), by Jiachang Xu – International Center for Mathematical Sciences (ICMS – Sofia) Zoom link: https://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: November 16, 2023, 2:00 pm Place: Room 403, IMI - BAS Speaker: Peter Dalakov, IMI-BAS Course title: Invariant theory, homogeneous projective varieties, and momentum maps Abstract: Let f:K\to U(V) be a unitary representation of a compact Lie group K with Lie algebra \mathfrak k . This series of talks will be devoted to some recent developments based on relations between the following three classical notions. The ring of K -invariant polynomials \mathbb C[V]^K is finitely generated by homogeneous elements, by a theorem of Hilbert, but the proof is notoriously nonconstructive. The degrees of a minimal set of generators are canonically determined by f , and will be the focus of the discussion. The K -equivariant momentum map \mu:\mathbb P(V)\to \mathfrak [...]

Algebra and Logic Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Algebra and Logic Seminar will be held in hybrod format (in Room 578 of IMI - BAS and online via Zoom) on November 17, 2023 (Friday) at 1:00 pm (UTC+2). A talk on: Noncommutative invariants of dihedral groups will be delivered by Boyan Kostadinov (IMI - BAS, Bulgaria). Abstract. We consider the 2-generated free metabelian associative and Lie algebras over the complex field and the invariants of the dihedral groups of finite order acting on these algebras. In the associative case we find a finite set of generators of the algebra of invariants. In the Lie case, when the algebra of invariants is not finitely generated, we give a minimal system of generators of the invariants in the commutator [...]

Didactical Modeling Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the seminar Didactical Modeling will be held on November 20, 2023, at 2:30 pm in Room 278 of IMI – BAS. A talk on: Scoring problems and using scales in standardized assessments will be delivered by Prof. Kiril Bankov.

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: November 21, 2023, 2:00 pm Place: Room 403, IMI - BAS Speaker: Peter Dalakov, IMI-BAS Course title: Invariant theory, homogeneous projective varieties, and momentum maps Abstract: Let f:K\to U(V) be a unitary representation of a compact Lie group K with Lie algebra \mathfrak k . This series of talks will be devoted to some recent developments based on relations between the following three classical notions. The ring of K -invariant polynomials \mathbb C[V]^K is finitely generated by homogeneous elements, by a theorem of Hilbert, but the proof is notoriously nonconstructive. The degrees of a minimal set of generators are canonically determined by f , and will be the focus of the discussion. The K -equivariant momentum map \mu:\mathbb P(V)\to \mathfrak [...]

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: November 23, 2023, 2:00 pm Place: Room 403, IMI - BAS Speaker: Peter Dalakov, IMI-BAS Course title: Invariant theory, homogeneous projective varieties, and momentum maps Abstract: Let f:K\to U(V) be a unitary representation of a compact Lie group K with Lie algebra \mathfrak k . This series of talks will be devoted to some recent developments based on relations between the following three classical notions. The ring of K -invariant polynomials \mathbb C[V]^K is finitely generated by homogeneous elements, by a theorem of Hilbert, but the proof is notoriously nonconstructive. The degrees of a minimal set of generators are canonically determined by f , and will be the focus of the discussion. The K -equivariant momentum map \mu:\mathbb P(V)\to \mathfrak [...]

Algebra and Logic Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Algebra and Logic Seminar will be held online on November 24, 2023 (Friday) at 1:00 pm (UTC+2) with two talks. At 1:00 pm (UTC+2) Dimitrinka Vladeva (IMI - BAS) will deliver a talk on Catalan numbers and additively idempotent semirings At 2:00 pm (UTC+2) Roussanka Loukanova (IMI - BAS) will deliver a talk on Semantics of Propositional Attitudes in Type-Theory of Algorithms Title: Catalan numbers and additively idempotent semirings Abstract. The purpose of the present talk is to provide new applications of remarkable Catalan numbers. In Richard Stanley’s book Enumerative Combinatorics, Volume II (Cambridge University Press) there are many combinatorial objects that are counted by the Catalan numbers as well as applications in graph theory, Young diagrams, lattice theory, real matrices, [...]

Mathematical Modelling and Numerical Analysis Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The seminar of the Mathematical Modeling and Numerical Analysis Department will have its next meeting as follows: Date: November 28, 2023, 2:00 pm Place: Conference Room of IMI - BAS Title: Application of Mathematical and Statistical Models and Methods in Forest and Agricultural Land Monitoring Using Remote Sensing Data Speakers: Prof. Lachezar Filchev, Ch. Assist. Prof. Desislava Ganeva, Ch. Assist. Prof. Ilina Kamenova and Ch. Assist. Prof. Zlatomir Dimitrov from ICIT - BAN  

Scientific seminar of the Information Modeling Department

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Information Modeling Seminar will be held on November 28 (Tuesday), at 2 p.m., in room 578 of IMI-BAS. Svetoslav Hadjiivanov, a full-time PhD student, will deliver a talk on: Revolutionizing .NET with the Actor Model: The End of Traditional Encapsulation? Abstract: The actor model is revolutionizing the way we build applications by moving past the traditional idea of encapsulation in object-oriented programming. This model is perfect for today's computers with multiple CPU cores, where old-school methods fall short, leading to race conditions and other concurrency issues. In this seminar, we'll introduce you to the basics of this effective approach. Proto.Actor, our toolkit of choice, blends the strength of both new and time-tested practices, making it a solid fit for industries [...]

Algebra and Logic Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Algebra and Logic Seminar will be held in hybrod format (in Room 578 of IMI - BAS and online via Zoom) on December 1, 2023 (Friday) at 1:00 pm (UTC+2). A talk on: Characterization of Ideals of Q-algebras Related to its G-part will be delivered by Jörg Koppitz (IMI - BAS, Bulgaria). Abstract. In this presentation, we study the G -part of Q -algebras X , i.e. the set G(X)=\{x\in X:0x=x\} . We show that G(X) is an abelian group, whenever G(X) is an ideal and characterize all Q -algebras X such that G(X) is an ideal of X . Moreover, we show that, up to isomorphism, there is only one Q -algebra X with G(X)=X , [...]

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: December 5, 2023, 2:00 pm Place: Room 403, IMI - BAS Speaker: Bogdan Stankov, IMI-BAS Title: Recent developments in the study of Følner functions For more information: https://icms.bg/recent-developments-in-the-study-of-folner-functions-talk-by-bogdan-stankov/  

National Seminar on Probability and Statistics

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the National Seminar on Probability and Statistics will be held on December 6, 2023, at 2:00 p.m. in Room 503 of the Institute of Mathematics and Informatics. A talk on: Brownian Motion Conditioned to Spend Limited Time Outside a Bounded Interval - An Extreme Example of Entropic Repulsion will be delivered by Dominic Т. Schickentanz (TU Darmstadt). Abstract. We condition a Brownian motion on \mathbb{R}_{\ge 0} on spending a total of at most s>0 time units outside a bounded interval. We describe the resulting process in terms of an SDE and discuss the surprising result in the context of entropic repulsion. Moreover, we explicitly determine the exact asymptotic behavior of the probability that a Brownian motion on [0,T] [...]

ICMS Geometry Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next session of the Geometry Seminar of ICMS will be held on Wednesday, December 6th, at 16:00, in room 403 and via Zoom. A talk on: Introduction to tropical modifications (II) will be delivered by Nikita Kalinin – International Center for Mathematical Sciences (ICMS – Sofia). Zoom link: https://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09  

ICMS Geometry Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next session of the Geometry Seminar of ICMS will be held on Wednesday, December 6th, at 16:00, in room 403 and via Zoom. A talk on: Valuations of Higher Rank will be delivered by Andrei Benguş-Lasnier – International Center for Mathematical Sciences (ICMS – Sofia). Zoom link: https://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09  

Annual Scientific Session of the Mathematical Modeling and Numerical Analysis Department

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The Annual Scientific Session of the Mathematical Modeling and Numerical AnalysisDepartment will be held on December 14, 2023 - Thursday, in room 503 at 10:00 a.m. Dedicated to the memory of Prof. Svetoslav Markov (1943 - 2023) Program 10:00 -10:20 Михаил Кръстанов, Маргарита Николова, "A sufficient condition for small-time local controllability" 10:20 -10:40 Петър Рашков, Владимира Суванджиева, "Модел на НЕТоза в ранния стадий на Systhemic Lupus Ertyhematosus" 10:40 -11:00 Ирина Георгиева, Clemens Hofreither, "Computation of polynomial and rational approximations in complex domains" 11:00-11:20 Кафе пауза 11:20- 11:40 Евгения Попова, "Chemical reaction networks in terms of proper and directed intervals" 11:40- 12:00 Иван Бажлеков, "Fractional derivatives in the mathematical modelling II." 12:00- 12:20 Невена Илиева-Литова, "Моделиране на зарядовата зависимост на биологичната активност на линейни антимикробни [...]

Annual Scientific Session of the Department of Algebra and Logic

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The Annual Scientific Session of the Algebra and Logic Department for 2023 will be held on December 15, 2023, at 9:55 am in Room 578 of IMI - BAS and online via Zoom. Link to the Zoom session: https://us02web.zoom.us/j/88421224798?pwd=UFh4d3hFM2lFN0RZVThEQmRoSVZ6QT09  PROGRAMME 9:55 – 10:00 Opening 10:00 – 10:30 Ivan Chipchakov: Diophantine and cohomological dimensions of fields 10:30 – 10:50 Elitza Hristova: Some new results on the GL(n)-module structure of relatively free algebras and applications to noncommutative invariant theory 10:50 – 11:00 Break 11:00 – 11:30 Hristo Iliev: On the Tschirnhausen module of multiple coverings and some applications 11:30 – 11:50 Veselin Filev: A Sampling Approach for Tackling Large-Scale Linear Optimization Problems 11:50 – 11:55 Break 11:55 – 12:15 Marin Genov: Some Aspects of Holomorphy over Finite-Dimensional Commutative [...]

Annual Scientific Session of ICMS-Sofia

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The Annual Scientific Session of the International Center for Mathematical Sciences - Sofia will be held on December 15, 2023 – Friday, in room 403 at 01:00 P.M. Programme 13:00-13:15          Oleg Mushkarov, Opening remarks 13:15-13:30           Valdemar Tsanov, On nonconvexity of momentum maps 13:30-13:45           Mikhail Shkolnikov, Exact solutions in harmonic sandpile dynamics 13:45–14:00        Break 14:00-14:15           Andrei Bengus-Lasnier, Computing Milчетна чnor numbers with multiplicities for curves 14:15-14:30           Antoni Rangachev, Flat families of curves 14:30-14:45           Jiachang Xu, Aspects of non-Archimedean geometry 14:45-15:00         Break 15:00-15:15           Maryam Bajalan, Polycyclic and multivariable codes over finite rings 15:15-15:30           Hamed Pejhan, Wigner’s elementary systems in de Sitter spacetime and their holographic interpretation 15:30-15:45         Break 15:45–16:00          Yingdi Qin, [...]

Fourth International Conference Women in Mathematics in South-Eastern Europe 2023

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

International Center for Mathematical Sciences – Sofia (ICMS-Sofia) and Institute of the Mathematical Sciences of the Americas at the University of Miami (IMSA) organize Fourth International Conference Women in Mathematics in South-Eastern Europe   The main goal of these events is to celebrate women in Mathematics, disseminate new results and create new long-term collaborations among scientists in South-Eastern Europe. We hope Women in Mathematics of South-Eastern Europe will attract the attention of young researchers and researchers from less-favoured countries. More data is coming soon on https://icms.bg/fourth-international-conference-women-in-mathematics-in-south-eastern-europe/.

Annual Scientific Session of the Mathematics and Informatics Education Department

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The Annual Scientific Session of the Department of Mathematics and Informatics Education will be held on December 18, 2023, at 1:00 pm in Room 478 of the Institute of Mathematics and Informatics. Please send your talk proposals to lazarov@math.bas.bg and albena@math.bas.bg no later than December 8, 2023. PROGRAM

Annual Scientific Session of the Operations Research, Probability and Statistics Department

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The Annual Scientific Session of the Operations Research, Probability and Statistics Department will be held on December 19, 2023 (Tuesday) at 10:00 a.m. in room 503 of IMI-BAN. PROGRAM First part 10:00 - 10:20 Dragomir Nedelchev Exploiting the gap between real-world and risk-neutral probability measures 10:20 - 10:40 Hristo Sariev Different characterizations of exchangeable measure-valued Pólya urn sequences 10:40 - 11:00 MihailKrastanov, Nadezhda Ribarska Необходими условия за оптималност, използващи мерки за некомпактност 11:00 - 11:20 Tsvetelin Zaevski Относно някои композитни Американски опции 11:20 - 11:40 Maroussia Bojkiva, Nikolay Yanev Многотипни разклоняващи се процеси с нехомогенна имиграция 11:40 - 12:00 Mladen Savov Факторизация на Винер-Хопф Second Part 13:00 - 13:20 Penka Mayster, Assen Tchorbadjieff Total progeny of the Negative-Binomial reproduction of particles described by the [...]

Annual Scientific Session of the DEMF Department

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The Differential Equations and Mathematical Physics Department will held its ANNUAL SCIENTIFIC SESSION on December 20, 2023, in Room 478 of IMI. 14:00 – 14:15 Чл.-кор. дфн Стойчо Язаджиев: Black hole no-hair theorem for self-gravitating time-dependent spherically symmetric multiple scalar fields 14:14 – 14:30 Доц. д-р Тихомир Вълчев Квазирационални решения на едно интегруемо обобщение на уравнението за феромагнетика на Хайзенберг 14:40 – 14:45 Доц. д-р Александър Стефанов: New type of dNLS equations related to Kac-Moody algebra A2(1) 14:45 – 15:00 Мат. д-р Милен Иванов: contact defects / анализ на данни за американските консули 1776-1865 15:00 – 15:15 Доц. д-р Георги Бояджиев: Пространствено-зависим SEIR модел в епидемиологията.  

Annual Scientific Session of the Mathematical Linguistics Department

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Annual Scientific Session of the Mathematical Linguistics Department of IMI - BAS December 22, 2023, 10:00 am 10:00 - 10:15 Иван Держански, Олена Сирук,от Българските неопределителни местоимения с елемента си и съответствията им в украински език 10:15 - 10:30 Александра Николова, Интерактивно обучение и сериозни игри 10:30 - 10:45 Иван Крачанов, Игровизиран краудсорсинг в помощ на семантичната трансформация на дигиталните библиотеки 10:45 - 11:00 Галина Богданова, Тодор Тодоров, Николай Ноев, Дигитална достъпност за хора със специални потребности: проучвания, концепции и модели 11:00 - 11:15 Евгения Николова, Стандарти за дигитализация на културно-историческото наследство и тяхната роля в правната сигурност 11:15 - 11:30 Емануела Митрева, Подходи за персонализация при изучаване на културното наследство 11:30 - 11:45 Десислава Панева-Маринова, Максим Гойнов, Радослав Павлов, Детелин Лучев, CultIS: софтуерна [...]

Algebra and Logic Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Algebra and Logic Seminar will be held in hybrid format in Room 578 of IMI - BAS and online via Zoom on January 8, 2024 (Monday) at 1:00 pm (UTC+2). A talk on: On the exceptional series and its siblings will be delivered by Bruce Westbury (retired from University of Warwick, UK). Abstract. The exceptional series is the following series of eight simple Lie algebras: A1, A2, G2, D4, F4, E6, E7, E8 Consider each Lie algebra, g, as a representation of the group Aut(g). Then the centraliser algebras of the first five tensor powers of g have common structure. First, they have the same branching rules. We introduce a parameter so that the exceptional series is a set [...]

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: January 9, 2024, 2:00 pm Place: Room 403, IMI - BAS Speaker: Antoni Rangachev, IMI-BAS Title: Stratified Morse theory and the critical locus of a linear functional Further information: https://icms.bg/stratified-morse-theory-and-the-critical-locus-of-a-linear-functional-talk-by-antony-rangachev/ Abstract. In this talk I will use stratified Morse theory to relate the number of critical points of a generic linear functional on a complex analytic manifold M to the Euler characteristics of M and a generic hyperplane slice of M.

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: January 11, 2024, 2:00 pm Place: Room 403, IMI - BAS Speaker: Antoni Rangachev, IMI-BAS Title: The Milnor number of a smoothable curve Further information: https://icms.bg/the-milnor-number-of-a-smoothable-curve-talk-by-antony-rangachev/ Abstract. In this talk I will derive an algebraic formula for the Milnor number of a smoothable complex analytic curve singularity X by relating it to the Euler characteristic of its smoothing, which in turn I will relate to the multiplicity of the Jacobian ideal of X and and the multiplicity of X at its singular point. If time permits I will discuss generalizations to higher dimensions. This is a report on a joint work with Gaffney and Bengus-Lasnier.  

Didactical Modeling Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the seminar Didactical Modeling will be held on January 15, 2024, at 2:30 pm in Room 278 of IMI – BAS. A talk on: The Bhaskara's methodology "Watch!" will be delivered by Prof. Ivan Tonov.

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: January 16, 2024, 2:00 pm Place: Room 403, IMI - BAS Speaker: Carlos Varea (Universidade Tecnológica  Federal do Paraná - Campus Cornélio Procópio, Brazil) Title: The H-flux on flag manifolds generated by infinitesimal T-duality Further information: https://icms.bg/the-h-flux-on-flag-manifolds-generated-by-infinitesimal-t-duality-talk-by-carlos-varea/ Abstract. In this talk we present a new correspondence for pairs (\mathbb{F},H) formed by a flag manifold \mathbb{F} together with an $H$-flux on \mathbb{F} . Given its role within our correspondence, infinitesimal T -duality may be viewed as a source of H -flux, in the sense that it contributes towards taking fluxless pairs (\mathbb{F},0) to pairs (\mathbb{F}^\vee, H^\vee) carrying nontrivial flux H^\vee\neq 0 . We also illustrate how our correspondence exchanges complex structures with symplectic ones up to B -transformations. This is a [...]

Mathemaical Foundations of Informatics Seminar in Veliko Tarnovo

Veliko Tarnovo University 2, Teodosiy Tarnovski Str., Veliko Tarnovo

A meeting of the Seminar on Mathematical Foundations of Informatics will be held in Veliko Tarnovo on January 17, 2024, at 4 pm, in Room 502 of the Faculty of Mathematics and Informatics of the Veliko Tarnovo University. A talk on Build your own digital device, even a multicore and multithreaded  icrocontroller with FPGA will be delivered by Dushan Bikov, Gotse Delchev University in Stip. Abstract: The use of Field-Programmable Gate Arrays (FPGAs) plays an essential role in providing flexibility for digital design. We then delve into practical insights on utilizing and constructing Intellectual Property (IP) cores within the FPGA framework. In addition to this, a new type of multithreaded and multicore microcontroller will be presented. The aim is to provide more computing power [...]

Joint meeting of the Algebra and Logic Seminar and the ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

A joint meeting of the Algebra and Logic Seminar and the Seminar of the International Center for Mathematical Sciences will be held on January 18, 2024 (Thursday) at 1:00 pm (UTC+2) in Room 403 of IMI - BAS and online via Zoom. A talk on Nilpotent algebras, groups and beyond will be delivered by Yuri Bahturin (Memorial University of Newfoundland, Canada) (joint work with Alexander Olshanskii). Abstract: We study various correspondences between finite-dimensional nilpotent algebras and (quasi)groups similar to those given by the circle product in the case of associative algebras or by the Baker-Campbell-Hausdorff formulas in the the case of Lie algebras or their generalizations. In the particular case of Malcev's correspondence, we obtain some new results about groups using Lie algebras and [...]

Inaugural lecture by Prof. Peter V. Danchev

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

On January 19, 2024, Friday, at 3:30 pm, in Room 503 of IMI-BAS, Prof. Danila Cherkashin will deliver an inaugural lecture on: Decomposition of matrices over an arbitrary field as a sum of periodic matrices and nilpotent matrices of order 2  

Inaugural lecture by Assoc. Prof. Stoyu Barov

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

On January 22, 2024, Monday, at 1:00 pm, in Room 478 of IMI-BAS, Assoc. Prof. Stoyu Barov will deliver an inaugural lecture on: On closed sets with convex projections in separable Hilbert spaces"   Abstract.  We discuss closed sets in R^n and in Hilbert space l^2 all of whose shadows (projections onto hyperplanes) are convex. Among other theorems,  we show that if C is a closed and nonconvex set in Hilbert space l^2 such that the closures of the projections onto all hyperplanes are convex and proper, then C must contain a closed topological copy of l^2 .

Joint Seminar of the Analysis, Geometry and Topology Department

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Joint Seminar of Analysis, Geometry and Topology Department will be held on January 23, 2024 at 2:00 pm (UTC+2)  in Room 478 of IMI. A talk on: Complex Dirac structures on flag manifolds  will be delivered by Carlos Augusto Bassani Varea, Universidade Tecnológica Federal do Paraná, Brazil. Everybody is invited. Abstract.In this talk we present a description of the invariant complex Dirac structures with constant real index on a maximal flag manifold in terms of the roots of the Lie algebra which defines the flag manifold. As a particular case, when the real index is zero, we have the description of all invariant generalized complex structures on a maximal flag manifold. We also present a classification of the complex Dirac [...]

General Meeting of the Scientists and the Scientific Council of IMI-BAS

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Pursuant to item 4.2 of the Operational Regulations of IMI, a joint meeting of the General Meeting of the Scientists at IMI and the Scientific Council of IMI will be held on January 24, 2024 (Wednesday) at 11:00 a.m. in Room 055 "Acad. Stefan Dodunekov", floor -1 of IMI, with the following agenda: 1. Adoption of the research and financial report for the activities of IMI in 2023. 2. Miscellaneous. The members of the GMS and the Scientific Council of IMI are obliged to attend the meeting. Information about membership in the GMS could be given by Galya Stoyanova, room 215 at IMI, ext. 3819. Proposals for minutes keeper, tellers and changes in the agenda of the meeting are also accepted by Galya Stoyanova. [...]

National Seminar on Probability and Statistics

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the National Seminar on Probability and Statistics will be held on January 24, 2024, at 2:00 p.m. in Room 503 of the Institute of Mathematics and Informatics. A talk on: Wave field source localization using antenna arrays as a statistical problem of multidimensional linear system parameter estimation will be delivered by Alexander Varypaev (National Institute of Geophysics, Geodesy and Geography, BAS). Abstract. The problem of statistical estimation of the coordinates of wave field sources from observations masked by additive random noise is considered. A likelihood-based estimate of source parameters is proposed for an unknown deterministic source function and additive noise correlated in time and space. The property of this estimate to suppress spatially correlated noise is mathematically justified. A statistical justification [...]

Geometry Seminar of ICMS

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next session of the Geometry Seminar of ICMSwill be held on Wednesday, January 24, 2024, at 16:00, in room 403 and via Zoom.A talk on:Introduction to Derived Algebraic Geometry and deformation theorywill be delivered by Yingdi Qin, IMI-BAS.Zoom link:https://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09

Didactical Modeling Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the seminar Didactical Modeling will be held on January 29, 2024, at 2:30 pm in Room 278 of IMI – BAS. A talk on: Interesting facts about the construction of “perpetual calendars” will be delivered by Assoc. Prof. Valentin Hristov.

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: January 30, 2024, 2:00 pm Place: Room 403, IMI - BAS Speaker: Vladimir Mitankin, IMI - BAS Title: Density of Hasse failures for diagonal affine cubic surfaces Further information: https://icms.bg/density-of-hasse-failures-for-diagonal-affine-cubic-surfaces-a-talk-by-vladimir-mitankin/ Abstract. А question of Mordell asks which integers are the sum of three cubes provided that there are no local obstructions to that. While Mordell’s question seems out of reach with the current machinery, it is widely believed that every integer not congruent to 4 or 5 mod 9 is a sum of three integral cubes. If, instead of the sum of three cubes, a general ternary cubic is considered, local conditions no longer suffice for solubility, i.e. the integral Hasse principle may fail. In this talk we shall apply the integral version of [...]

Applied Mathematics Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Temporal networks, Tensors, and applications to ML Speaker: Prof. Ognyan Kounchev Date: January 31, 2024 Time: 3:00 pm Place: ... Abstract: Recently, temporal networks got an increasing interest, related to their numerous applications in real-life data analysis. The temporal networks (more mathematically, “graphs depending on time”) are a typical example of a Tensor – the adjacency matrix depends on several parameters and is a tensor (in the mathematical sense of the word). We present some recent results about the structure of the spectrum of the normalized Laplacian in the case of “slowly varying temporal networks”. The detailed structure of the spectrum gives rise of the notion of “constant block Jacobi model”, which has closed-form solution for the spectrum and the eigenfunctions. This brings a [...]

Geometry Seminar of ICMS

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next session of the Geometry Seminar of ICMS will be held on Wednesday, January 24, 2024, at 16:00, in room 403 and via Zoom. A talk on: Derived Deformation Theory and Formal Moduli Problem will be delivered by Yingdi Qin, IMI-BAS. Zoom link: https://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09 Abstract: Derived deformation theory studies the formal neighborhoods of moduli spaces. The classical work of Kodaira-Spencer on deformation of complex manifolds tells that the dg Lie algebra A^(0,*)(X,TX) controls the deformations of the complex manifold. The example illustrates the following general principle: A dg Lie algebra gives rise to a deformation functor by considering the  Maurer-Cartan elements of the dg Lie algebra tensoring with the maximal ideal of an Artin local ring. This idea is explored by many people, including  Quillen, [...]

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: February 6, 2024, 2:00 pm Place: Room 403, IMI - BAS Speaker: Vladimir Mitankin, IMI - BAS Title: A categorical view of singularity theory I Further information: https://icms.bg/a-categorical-view-of-singularity-theory-i-and-ii-talks-by-paul-horja/ Abstract. The mirror symmetry phenomenon was discovered by string theorists more than thirty years ago as an equivalence of two physical theories associated with very different geometries. The categorical point of view on this remarkable conjecture was famously introduced by M. Kontsevich in his 1994 ICM talk. As it became clear over time, homological mirror symmetry provides new approaches to many topics in symplectic and algebraic geometry. In these two talks, I will present a brief overview of the conjecture as well as some results inspired by mirror symmetry and obtained in joint work with [...]

Geometry Seminar of ICMS

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next session of the Geometry Seminar of ICMS will be held on Wednesday, February 7, 2024, at 16:00, in room 403 and via Zoom. A talk on: Introduction to curve counting will be delivered by Mikhail Shkolnikov, IMI-BAS. Zoom link: https://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09 Abstract: This talk is intended as a very gentle introduction to the classical subject of enumerative geometry concerned with problems of counting algebraic curves with prescribed properties. In the realm of classical planimetry, we know that there exists a single circle passing through a collection of three points, provided that these points are generic. Here “generic” simply means that the points are not collinear, i.e. don’t belong to the same line but could refer to some other open condition in a different [...]

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: February 8, 2024, 2:00 pm Place: Room 403, IMI - BAS Speaker: Vladimir Mitankin, IMI - BAS Title: A categorical view of singularity theory II Further information: https://icms.bg/a-categorical-view-of-singularity-theory-i-and-ii-talks-by-paul-horja/ Abstract. The mirror symmetry phenomenon was discovered by string theorists more than thirty years ago as an equivalence of two physical theories associated with very different geometries. The categorical point of view on this remarkable conjecture was famously introduced by M. Kontsevich in his 1994 ICM talk. As it became clear over time, homological mirror symmetry provides new approaches to many topics in symplectic and algebraic geometry. In these two talks, I will present a brief overview of the conjecture as well as some results inspired by mirror symmetry and obtained in joint work with [...]

Mathematical Foundations of Informatics Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Mathematical Foundations of Informatics seminar will be held on February 8, 2024, at 3:00 p.m. in Room 256 of the Institute of Mathematics and Informatics. A talk on: Extremal problems in Euclidean combinatorial geometry will be delivered by Assoc. Prof. Danila Cherkashin. Abstract.  I will talk about several problems in the intersection of extremal combinatorics and Euclidean geometry. Recent results on the Steiner tree problem, Gilbert-Steiner problem, and Nelson-Hadwiger problem will be presented. The seminar will be streamed at  https://meet.jit.si/IMI-MOI-14400

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: February 13, 2024, 2:00 pm Place: Room 403, IMI - BAS Speaker: Jean-Pierre Gazeau (APC, Université Paris - Cité) Title: Quantum circuit complexity for light polarisation or complexity with no complex numbers Further information: https://icms.bg/quantum-circuit-complexity-for-light-polarisation-or-complexity-with-no-complex-number-talk-by-jean-pierre-gazeau/ Abstract. I will present a form of quantum circuit complexity that extends to open systems. To illustrate the methodology, I focus on a basic model where the Hilbert space of states is represented by the Euclidean plane. Specifically, the investigation is about the dynamics of mixed quantum states as they undergo interactions with a sequence of gates. The approach involves the analysis of sequences of density matrices. Each density matrix evolves within the framework of a Gorini-Kossakowski-Lindblad-Sudarshan (GKLS) process during the time interval between consecutive gates. Notably, when [...]

National Seminar on Probability and Statistics

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the National Seminar on Probability and Statistics will be held on February 14, 2024, at 2:00 p.m. in Room 503 of the Institute of Mathematics and Informatics. A talk on: Computable inference for generalised Wright-Fisher processes will be delivered by Nathan Judd (University of Warwick, UK). Abstract.In this talk, we will introduce a class of [0,1]-valued Markov processes with jumps that, as signals in hidden Markov models, admits a computable (exact) filter. By computable filter we mean that each filtering distribution, i.e., the law of the signal at a time t given the data up to time t, is explicitly and exactly available as a finite mixture of Dirichlet distributions. We exploit the tractability of the Wright-Fisher diffusion, in particular, its [...]

Geometry Seminar of ICMS

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next session of the Geometry Seminar of ICMS will be held on Wednesday, February 7, 2024, at 16:00, in room 403 and via Zoom. A talk on: Refined curve counting will be delivered by Mikhail Shkolnikov, IMI-BAS. Zoom link: https://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09 Abstract: Refining an enumerative problem upgrades the numerical solution to a polynomial so that its specialization gives the original number. A prototypical example of such refinement arises in the tropical curve counting from replacing Mikhalkin multiplicities, corresponding to counting complex curves, with Block-Goettsche multiplicities. I will speak about the invariance of this count and its various interpretations.

Conference “Dynamic Mathematics in Education”

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The Department of Education in Mathematics and Informatics of IMI-BAS is organizing a one-day conference "Dynamic Mathematics in Education", which will be held on February 17, 2024 at IMI-BAS. The aim is to share and analyze the experience gained from the use of dynamic educational environments in the learning process (at all levels and in various forms). Participants will have 10 minutes to present their work related to education in mathematics and information technology, which contains some dynamic form of presenting the learning content and/or conducting the teaching process. The works can also be presented as a poster. We expect: presentations based on computer environments such as GeoGebra, GEONExT, Elica, Scratch, Comenius Logo, etc .; devices and systems for dynamic presentation of mathematical facts; [...]

Science and Innovation Fair – Innofair 2024

Античен културно-комуникационен комплекс „Сердика“ пл. Независимост", София

The annual Science and Innovation Fair, Innofair 2024, will be held on February 17, 2024 (Saturday)= The contest is organized by the Institute of Mathematics and Informatics in partnership with the Young Talents Club, and is part of the initiatives steming from the "Education with Science" Program. The science fair aims to discover scientific talents among young people aged 14-19, to assist in their future development and to give an international forum to their ideas, discoveries and innovations. The authors of the top works (up to 15) will be invited to present their works to a jury and the public on February 17, 2024, and will be awarded a certificate of excellence. The presentation session will take place in the Sofia Largo, the area [...]

Scientific seminar of the Information Modeling Department

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Information Modeling Seminar will be held on February 22 (Thursday), at 2 p.m., in room 503 of IMI-BAS. A talk on: Integrating relational data and unstructured big data with a functional SQL-like query language will be delivered by Senior Assist. Prof. Boyan Kolev. Abstract: Polystore systems have been proposed to provide integrated access to multiple, heterogeneous data stores through a single query engine. In particular, much attention is being paid on the integration of relational data with unstructured big data typically stored in HDFS. One typical legacy solution is to use a relational query engine that allows SQL-like queries to retrieve data from HDFS, which requires the system to provide a relational view of the unstructured data and hence is [...]

Algebra and Logic Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Algebra and Logic Seminar will be held online via Zoom on February 23, 2024 (Friday) at 1:00 pm (UTC+2). A talk on: Invariant subalgebras of the rational Cherednik algebra will be delivered by Niall Hird (University of Glasgow, UK). Abstract. The rational Cherednik algebra is a degeneration of the double affine Hecke algebra and an object of interest to many representation theorists, it also has strong connections to integrable systems. In my talk I will discuss two subalgebras that arise from considering the invariants of the action of reductive subgroups of the special linear group. In particular we will examine the centres of these invariant subalgebras and compare with the algebra of invariants of the centre of the entire [...]

“Doctor of Science” dissertation thesis defense

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The Institute of Mathematics and Informatics of the Bulgarian Academy of Sciences and the Scientific Jury for awarding the scientific degree "Doctor of Science" hereby announce that on February 26, 2024, at 4:00 pm (UTC+2), a hybrid open meeting will be held (in Room 403 of IMI - BAS and in Zoom) of the Scientific Jury for the defense of the dissertation thesis on: Symplectic Topology, Non-commutative Geometry, and Mirror Symmetry by Prof. Dr. Lyudmil Katzarkov in higher education area: 4. Natural Sciences, Mathematics and Informatics Professional field: 4.5. Mathematics Scientific specialty: Geometry and Topology. Chairman of the Scientific Jury: Prof. Stefan Ivanov, D.Sc., Corr. member of the BAS (FMI - Sofia University, IMI - BAS) Members of the Scientific Jury: Prof. Vesselin Drensky, [...]

Geometry Seminar of ICMS

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next session of the Geometry Seminar of ICMS will be held on Wednesday, February 28, 2024, at 16:00, in room 403 and via Zoom. A talk on: Linear embeddings of complex Grassmannians will be delivered by Ivan Penkov, Constructor University Bremen. Zoom link: https://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09 Abstract: A linear embedding of Grassmannians, one of which could possibly be isotropic, is an embedding which respects the generators of Picard groups. Several years ago A.S. Tikhomirov and I classified such embeddings when both Grassmannians are simultaneously usual Grassmannians or isotropic Grassmannians of the same type(orthogonal or symplectic). In this talk I will discuss also the mixed case. A classification as above has an application to the classification of infinite-dimensional linear ind-Grassmannians, and I shall  briefly explain this [...]

Preliminary defense of the dissertation of Danila Cherkashin for awarding the degree “Doctor of Science”

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

On March 12, 2024 (Tuesday), at 2:00 pm in the Conference Room of IMI-BAS, a preliminary defense will be held of the dissertation of Danila Cherkashin on: Extremal problems in Euclidean Combinatorial Geometry for awarding of the degree “Doctor of Science”. Everybody is invited. The dissertation can be found at the Library of IMI-BAS. The pre-defense can be watched at https://meet.jit.si/IMI-MOI-14400  

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: March 12, 2024, 2:00 pm Place: Room 403, IMI - BAS Speaker: Morgan Brown  (University of Miami) Title: The Cox ring perspective on birational geometry Further information: https://icms.bg/the-cox-ring-perspective-in-birational-geometry-talk-by-morgan-brown/ Abstract. The Mori program for birational classification of algebraic varieties attempts to classify algebraic varieties by producing canonical models, polarized by the canonical class. This is accomplished through a series of algebraic surgery operations, such as flips, flops, and divisorial contractions. A complementary viewpoint is that of the total coordinate ring or Cox ring. Here birational maps are understood by looking at the totality of all linear series on the variety, endowed with a ring structure directly analogous to that of the homogeneous coordinate ring of a projective variety. I will give an overview of [...]

ICMS Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

Time: March 14, 2024, 2:00 pm Place: Room 403, IMI - BAS Speaker: Morgan Brown  (University of Miami) Title: Cox rings and characterization of toric varieties Further information: https://icms.bg/the-cox-ring-perspective-in-birational-geometry-talk-by-morgan-brown/ Abstract. Recently Moraga and Svaldi proved a conjecture of Shokoruv, characterizing in the relative case toroidal morphisms as those which admit divisors with many components relative to the Picard rank. I will discuss the global version, proved in previous joint work with McKernan, Svaldi and Zong. The proof relies on characterizing the singularity type of the Cox ring, giving another example of the use of these invariants in birational geometry.

Mathemaical Foundations of Informatics Seminar in Veliko Tarnovo

Veliko Tarnovo University 2, Teodosiy Tarnovski Str., Veliko Tarnovo

A meeting of the Seminar on Mathematical Foundations of Informatics will be held in Veliko Tarnovo on March 18, 2024, at 4:30 pm, in Room 401 of Building 4 of the Veliko Tarnovo University. A talk on LCD Codes over Mixed Alphabets will be delivered by Maryam Bajalan, IMI - BAS. Abstract: In this presentation, we describe the structural properties of (Galois) linear complementary dual codes over mixed alphabets arising from finite chain rings. Our focus centres on providing a comprehensive characterization, outlining the conditions under which a given code falls into this category and it is Galois invariant. This leads to the study of the Gray image of FpFp[θ]-linear codes, where p ∈ {2,3} and θ ≠ θ2 = 0 , that provides Fp-linear [...]

ICMS Colloquium

Zoom

Time: 19.03.2024, Wednesday, 4:00 pm Place: Zoom only Lecturer: Vesselin Petkov (Université Bordeaux) Title: Dynamical zeta function for billiard flow Abstract: We will present briefly the connection between Riemann zeta function, Ruellle zeta function and dynamical zeta function. The last one is related to the billiard flow for the union D \subset R^d of a finite collection of pairwise disjoint strictly convex compact obstacles. Let \mu_j \in C , \Im \mu_j > 0 be the resonances of the Laplacian in the exterior of D with Neumann or Dirichlet boundary condition on \partial D . For d odd, u(t) = \sum_j e^{i |t| \mu_j} is a distribution in \mathcal{D}'(R \setminus \{0\}) and the Laplace transforms of the leading [...]

Geometry Seminar of ICMS

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next session of the Geometry Seminar of ICMS will be held on Wednesday, March 20, 2024, at 16:00, in room 403 and via Zoom. A talk on: Ellipsoid superpotentials: obstructing symplectic embeddings by singular algebraic curves will be delivered by Grigory Mikhalkin, University of Geneva. Abstract: How singular can be a local branch of a plane algebraic curve of a given degree d? A remarkable series of real algebraic curves was constructed by Stepan Orevkov. It is based on even-indexed numbers in the Fibonacci series: a degree 5 curve with a 13/2 cusp, a degree 13 curve with a 34/5-cusp, and so on. We discuss this and other series of algebraic curves in the context of the problem of symplectic packing of an ellipsoid [...]

Preliminary defense of the PhD dissertation of Dimitar Dobrev

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

On March 22 (Friday) at 11 a.m. in room 503 of IMI-BAS, a preliminary defense will be held of the dissertation project of Dimitar Dimitrov Dobrev on Artificial Intelligence -- Definition, Implementation and Implications to obtain the educational and scientific degree "doctor" in the field of higher education 4. Natural sciences, mathematics and informatics, professional division 4.5 Mathematics, scientific specialty "Mathematical logic". The draft dissertation is available at the IMI-BAS library and online at: https://dobrev.com/AI/Dobrev_PhD_v3.pdf  (main text) https://dobrev.com/AI/Dobrev_PhD_avtoref.pdf  (abstract in Bulgarian) https://dobrev.com/AI/Dobrev_PhD_abstract.pdf  (abstract in English). The pre-defense will be streamed also in ZOOM at: https://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 Everybody is invited. Algebra and Logic Department, IMI – BAS, http://www.math.bas.bg/algebra/seminarAiL/

Algebra and Logic Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Algebra and Logic Seminar will be held online via Zoom on March 22, 2024 (Friday) at 1:00 pm (UTC+2). A talk on: On the uniqueness of maximal solvable extensions of nilpotent Lie algebras will be delivered by Bakhrom A. Omirov (Harbin Institute of Technologies, Harbin, China and Romanovskiy Institute of Mathematics, Uzbekistan Academy of Sciences, Uzbekistan). Abstract.During the talk it will be shown that under certain condition an arbitrary complex finite-dimensional maximal extension of a nilpotent Lie algebra N is isomorphic to the semidirect sum of N and its maximal torus. A criterion of the completeness for a finite-dimensional solvable Lie algebra is established. Comparisons with some existing results will also be discussed. Link to the Zoom room: https://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09   Algebra and Logic [...]

Applied Mathematics Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

On constructions of spherical codes Speaker: Dr. Konstantin Vorob'ev Date: March 27, 2024 Time: 4:00 pm Place: Room 503 Abstract: In this talk, we review various approaches to construct spherical codes with a given coding distance. We also propose a new approach that allows us to find new codes on spheres in small dimensions. In particular, we find a previously unknown kissing arrangement of 40 spheres in R^5.

Geometry Seminar of ICMS

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next session of the Geometry Seminar of ICMS will be held on Wednesday, March 20, 2024, at 16:00, in room 403 and via Zoom. A talk on: Reading seminar of geometric Lubin-Tate theory will be delivered by Jiachang Xu, IMI - BAS. Abstract: This is reading seminar of geometry of Lubin-Tate theory, our goal is to understand the papers “M. J. Hopkins and B. H. Gross, Equivariant vector bundles on the Lubin-Tate moduli space” and “Ramero, Lorenzo On a class of étale analytic sheaves”. The first seminar we plan to go over the basis of deformation theory, formal group and necessary rigid geometry. Zoom link: https://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09  

Algebra and Logic Seminar

Institute of Mathematics and Informatics, BAS Akad.G.Bonchev St, bl. 8, 1113, Sofia

The next meeting of the Algebra and Logic Seminar will be held online via Zoom on March 29, 2024 (Friday) at 1:00 pm (UTC+2). A talk on: Generalized Definability of Discrete Time Interval-based Temporal Connectives will be delivered by Dimitar Guelev (Institute of Mathematics and Informatics, Bulgarian Academy of Sciences). Abstract.In Linear Temporal Logic with past (PLTL), expressive completeness implies that any first-order definable connective is also definable in the temporal language based on the Since and Until temporal operators. This is not the case about discrete time interval-based temporal logics with state-based semantics for the propositional variables. In this talk I prove the next best thing about the extension ITLNL of Moszkowski's discrete time propositional Interval Temporal Logic (ITL) by the neighbourhood modalities: given an interval-based connective # which admits [...]

Go to Top