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X-WR-CALNAME:Institute of Mathematics and Informatics
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X-WR-CALDESC:Събития за Institute of Mathematics and Informatics
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DTSTART:20250330T010000
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DTSTART;TZID=Europe/Sofia:20250411T160000
DTEND;TZID=Europe/Sofia:20250411T173000
DTSTAMP:20260406T104626
CREATED:20250410T165453Z
LAST-MODIFIED:20250410T165453Z
UID:17619-1744387200-1744392600@math.bas.bg
SUMMARY:Семинар на МЦМН
DESCRIPTION:Дата: 11.04.2025 г.\, 16:00 ч. \nМясто: Зала 403\, ИМИ – БАН \nДокладчик: Felipe Espreafico Guelerman\, Sorbonne Université – Paris \nДоклад: On Motivic and Arithmetic Donaldson-Thomas invariants \nДопълнителна информация: https://icms.bg/category/icms-seminar/ \nРезюме. Aiming to understand the relation to other “refined invariants”\, and especially their possible interpretation in quantum theory\, we explain how to obtain a quadratic\, A1-version of Donaldson-Thomas invariants from the motivic refinements first introduced in Kontsevich-Soibelman. Following ideas from Behrend\, Bryan and Szendroi\, we provide predictions for these invariants in a few simple examples\, mainly the computation of DT invariants of A3. Our main goal is to draw relationships with the literature\, including works of Levine\, Denef and Loser\, Azouri\, Pepin-Lehaulleur\, Srinivas among others. We begin with a brief introduction to A1-enumerative geometry and in the end\, we pose some further questions on possible extensions of our definitions. This is joint work with Johannes Walcher. We also comment on joint work in progress with Ran Azouri.
URL:https://math.bas.bg/event/%d1%81%d0%b5%d0%bc%d0%b8%d0%bd%d0%b0%d1%80-%d0%bd%d0%b0-%d0%bc%d1%86%d0%bc%d0%bd-30/
LOCATION:Институт по математика и информатика – БАН\, Block 8\, 1113 БАН IV км.\, София\, Bulgaria
CATEGORIES:Редовен семинар
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20250423T140000
DTEND;TZID=Europe/Sofia:20250423T153000
DTSTAMP:20260406T104626
CREATED:20250410T183443Z
LAST-MODIFIED:20250410T183443Z
UID:17623-1745416800-1745422200@math.bas.bg
SUMMARY:Семинар "Математическо моделиране и числен анализ"
DESCRIPTION:Поредната сбирка на СЕМИНАРА на секция \n“Математическо моделиране и числен анализ”  \nще се състои на  23.04.2025 г. (сряда) от 14:00 часа в зала 478 на ИМИ – БАН. \nДоклад на тема: \nMultiscale Leading Edge and Bulk Dynamics for Tumour Invasion in Fibrous Environment\nще изнесе Dr. Dumitru Trucu (University of Dundee\, Шотландия). \nРезюме: Despite all recent in vivo\, in vitro\, and in silico advances\, the understanding of the genuine biologically multiscale process of solid tumour invasion remains one of the greatest open questions for scientific community. In this talk we present novel mathematical multiscale moving boundary modelling and structural analytical approaches for tumour invasion. Specifically\, we focus on characterising mathematically key aspects of the dynamic interactions that the migratory cancer cells population and the accompanying matrix degrading enzymes (MDEs) have with the extracellular matrix (ECM) components\, and in particular with the ECM fibres. These are complex interactions enabled by a series of integrated multiscale systems\, which are at least two-scale in nature and share (and contribute to) the same tumour macro-dynamics (i.e.\, tissue-scale dynamics) but have independent-in-nature micro-dynamics (i.e.\, cell-scale dynamics). For instance\, on the bulk of the tumour\, of major interest is the dynamics of fibres degradation and structural realignment occurring at micro-scale as well as the immediate impact that this continuously changing field of oriented ECM fibres has over the tumour macro-dynamics. On the other hand\, the cell-scale proteolytic micro-dynamics occurring at the tumour invasive edge interacts with the peritumoural ECM fibres through the molecular fluxes of MDEs. This interfacial cell-scale interaction not only results in changes in the micro-scale structural distribution of peritumoural ECM fibres but also influences directly the changes of the overall tumour morphology. \nThe new mathematical multiscale modelling framework presented here aims to address the precise biological multiscale nature of these interactions between the cancer cell population and the surrounding fibrous environment during solid tumour invasion. This involves an appropriately derived novel 2D & 3D multiscale moving boundary modelling framework as well as state-of-the-art multiscale computational approaches. Furthermore\, this research paves the way for new multiscale analysis research avenues that builds on the novel concept of three-scale convergence that I established and introduced a while ago.\n 
URL:https://math.bas.bg/event/%d1%81%d0%b5%d0%bc%d0%b8%d0%bd%d0%b0%d1%80-%d0%bc%d0%b0%d1%82%d0%b5%d0%bc%d0%b0%d1%82%d0%b8%d1%87%d0%b5%d1%81%d0%ba%d0%be-%d0%bc%d0%be%d0%b4%d0%b5%d0%bb%d0%b8%d1%80%d0%b0%d0%bd%d0%b5-%d0%b8-%d1%87-8/
LOCATION:Институт по математика и информатика – БАН\, Block 8\, 1113 БАН IV км.\, София\, Bulgaria
CATEGORIES:Редовен семинар
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BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20250425T130000
DTEND;TZID=Europe/Sofia:20250425T140000
DTSTAMP:20260406T104626
CREATED:20250423T111012Z
LAST-MODIFIED:20250424T153714Z
UID:17652-1745586000-1745589600@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 25 април 2025 г. (петък) от 13:00 часа в зала 578 на ИМИ\nще се проведе заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nHilbert scheme of smooth projective curves and some easy examples\nще изнесе \nChangho Keem\n(Seoul National University\, South Korea).\nAbstract: Hilbert scheme is a parameter space for a family of projective algebraic varieties sharing a given fixed Hilbert polynomial.  In this talk\, we will discuss the following topics concerning the Hilbert scheme of smooth projective algebraic curves. \n1. Irreducibility problem of the restricted Hilbert scheme of curves. \n2. Some easy examples of reducible Hilbert schemes inside or outside the Brill-Noether range. \n3. The existence of more than expected dimensional components whose image under the moduli map has small codimension inside the moduli space of curves of genus g. \n  \nПоканват се всички желаещи да присъстват. \nОт секция „Алгебра и логика” на ИМИ – БАН\nhttp://www.math.bas.bg/algebra/seminarAiL/\n============================== =====================
URL:https://math.bas.bg/event/%d1%81%d0%b5%d0%bc%d0%b8%d0%bd%d0%b0%d1%80-%d0%b0%d0%bb%d0%b3%d0%b5%d0%b1%d1%80%d0%b0-%d0%b8-%d0%bb%d0%be%d0%b3%d0%b8%d0%ba%d0%b0-119/
LOCATION:Институт по математика и информатика – БАН\, Block 8\, 1113 БАН IV км.\, София\, Bulgaria
CATEGORIES:Редовен семинар
ORGANIZER;CN="%D0%A1%D0%B5%D0%BA%D1%86%D0%B8%D1%8F%20%D0%90%D0%BB%D0%B3%D0%B5%D0%B1%D1%80%D0%B0%20%D0%B8%20%D0%BB%D0%BE%D0%B3%D0%B8%D0%BA%D0%B0":MAILTO:algebra_logic_seminar@math.bas.bg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20250429T140000
DTEND;TZID=Europe/Sofia:20250429T153000
DTSTAMP:20260406T104626
CREATED:20250424T212823Z
LAST-MODIFIED:20250427T075255Z
UID:17670-1745935200-1745940600@math.bas.bg
SUMMARY:Съвместна сбирка на семинара на МЦМН и семинара "Алгебра и Логика"
DESCRIPTION:Съвместна сбирка на семинара на МЦМН и семинара “Алгебра и Логика” в ИМИ\, София\, ще се проведе идния вторник\, с доклад на Георги Томанов\, както следва.\n\nВторник\, 29-ти април\, 14:00 часа\, зала 403 на ИМИ-БАН.\nГеорги Томанов\, Université Claude Bernard\, Lyon 1.\nGroup action on homogeneous spaces and applications in number theory\n\nAbstract: Many longstanding conjectures and problems in number theory can be reformulated in terms of group actions on homogeneous spaces. This reformulation allows them to be tackled using\, alongside deep methods from algebra and algebraic geometry\, powerful tools from ergodic theory and dynamical systems. An example of the effectiveness of this approach is Margulis’s groundbreaking proof of the Oppenheim conjecture (formulated in 1929) concerning the values of quadratic forms at integer points. \nIn this talk\, aimed at a general audience\, we will describe recent results on the characterization of norm forms—a classical object in algebraic number theory—in terms of their values at integer points. These results answer natural questions and are related to still-open conjectures of Littlewood (from 1930) and of Cassels and Swinnerton-Dyer (from 1955). The proofs rely on studying the actions of maximal tori of algebraic groups on homogeneous spaces of arithmetic origin. \n\nПовече информация можете да намерите на страницата на семинара:\nhttps://icms.bg/category/icms-seminar/
URL:https://math.bas.bg/event/%d1%81%d1%8a%d0%b2%d0%bc%d0%b5%d1%81%d1%82%d0%bd%d0%b0-%d1%81%d0%b1%d0%b8%d1%80%d0%ba%d0%b0-%d0%bd%d0%b0-%d1%81%d0%b5%d0%bc%d0%b8%d0%bd%d0%b0%d1%80%d0%b0-%d0%bd%d0%b0-%d0%bc%d1%86%d0%bc%d0%bd-%d0%b8/
LOCATION:Институт по математика и информатика – БАН\, Block 8\, 1113 БАН IV км.\, София\, Bulgaria
CATEGORIES:Редовен семинар
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20250430T160000
DTEND;TZID=Europe/Sofia:20250430T173000
DTSTAMP:20260406T104626
CREATED:20250424T092412Z
LAST-MODIFIED:20250424T093036Z
UID:17661-1746028800-1746034200@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 30 април 2025 г. от 16:00 ч. в зала 403 и онлайн в Zoom: \nДоклад на тема \nBinary Quadratic Forms and Conway’s Topographs (Lecture 1 of 3)\n\nще изнесе Nikita Kalinin\, Guangdong Technion Israel Institute of Technology. \n\nСледващите две лекции ще бъдат на 07.05.2025 и 14.05.2025 от 16:00 ч.\n\nAbstract: Binary quadratic forms are as elementary as they are mysterious—much like prime numbers. In 1997\, John Conway introduced topographs\, a powerful geometric tool that provides a geometric visualization of binary quadratic forms and their values. These lectures will explore how topographs\, combined with telescoping summation techniques\, yield elegant formulas — some with intuitive geometric interpretations. For instance\, consider the following result: \nLet \n\(A = \big\{ (x\, y) \mid  x\,y\in \mathbb{Z}_{\geq 0}^2\, \det(x \ \ y) = 1 \big\}\,\) \nthe set of pairs of lattice vectors in the first quadrant spanning a parallelogram of oriented area 1. Then\, \n\(4 \displaystyle\sum_{(x\,y) \in A} \frac{1}{|x|^2 \cdot |y|^2 \cdot |x+y|^2} = \pi.\) \nLecture Outline \n1. Introduction to Binary Quadratic Forms and Conway’s Topographs\nWe will begin with the basics of binary quadratic forms and their classification\, followed by an introduction to Conway’s topographs—a visual and geometric framework for understanding them. \n2. Class Number Formula and Summation over Topographs\nBuilding on the first lecture\, we will explore the class number formula and how summation identities arise naturally from the structure of topographs. \n3. Evaluation of Lattice Sums via Telescoping over Topographs\nThe final lecture will focus on telescoping techniques\, demonstrating how they can be used to evaluate intricate lattice sums—such as the one above—with geometric meaning. \n\n\nZoom link:\nhttps://us02web.zoom.us/j/86186281353?pwd=6CARUygJaA3HiTNAt3norZQRFt8fIL.1
URL:https://math.bas.bg/event/%d1%81%d0%b5%d0%bc%d0%b8%d0%bd%d0%b0%d1%80-%d0%bf%d0%be-%d0%b3%d0%b5%d0%be%d0%bc%d0%b5%d1%82%d1%80%d0%b8%d1%8f-%d0%bd%d0%b0-%d0%bc%d1%86%d0%bc%d0%bd-15/
LOCATION:Институт по математика и информатика – БАН\, Block 8\, 1113 БАН IV км.\, София\, Bulgaria
CATEGORIES:Редовен семинар
ORGANIZER;CN="%D0%98%D0%BD%D1%81%D1%82%D0%B8%D1%82%D1%83%D1%82%20%D0%BF%D0%BE%20%D0%BC%D0%B0%D1%82%D0%B5%D0%BC%D0%B0%D1%82%D0%B8%D0%BA%D0%B0%20%D0%B8%20%D0%B8%D0%BD%D1%84%D0%BE%D1%80%D0%BC%D0%B0%D1%82%D0%B8%D0%BA%D0%B0%20-%20%D0%91%D0%90%D0%9D":MAILTO:office@math.bas.bg
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