An online session of the Algebra and Logic Seminar will be held on March 26, 2021 (Friday) at 1:00 p.m. A talk on Some axioms about rationality in infinite concurrent multiplayer games with ordered objectives and temporary coalitions in QCTL* will be delivered by Dimitar Guelev (IMI - BAS). Abstract. Temporal winning conditions appear in both terminating and infinite games. Reachability (guarantee) winning conditions appear in terminating games. Safety conditions and conditions higher up in the (Manna & Pnueli, 1989) hierarchy appear in non-terminating games. In a multiplayer game, the latter classes of winning conditions are natural to drive players into forming permanent coalitions as the longevity of a coalition needs to match the duration of its agenda, which may take entire infinite plays [...]

An online session of the Algebra and Logic Seminar will be held on March 19, 2021 (Friday) at 4:00 p.m. A talk on Some applications of transfinite numbers to algebra and some applications of number theory to transfinite numbers will be delivered by Andreas Weiermann (Ghent University, Belgium). Abstract.  In the first part we will survey the role of transfinite numbers in the study of Hilbert's basis theorem and its extension by MacLagan. To this end we associate ordinals to some natural well partial orderings related Cartesian products of the set of natural numbers and we apply this apparatus to monomial ideals in F[X_1,...,X_n] where F is a field. In the second part we use the machinery of Tauberian theorems to prove some structural results [...]

An online session of the Algebra and Logic Seminar will be held on March 5, 2021 (Friday) at 4:00 p.m. A talk on Finite presentability for metabelian groups, Lie algebras and restricted Lie algebras will be delivered by Dessislava Kochloukova, University of Campinas, Brazil. Abstract. In the first part of the talk we revisе the already known classifications of finite presentability (in terms of generators and relations) for metabelian groups and metabelian Lie algebras. The case of groups was solved by Robert Bieri and Ralph Strebel in 1980s and that of Lie algebras was done by Roger Bryant and John Groves in late 1990s. In the last part of the talk we discuss new results about the classification of finitely presented metabelian restricted Lie algebras [...]

An online session of the Algebra and Logic Seminar will be held on February 26, 2021 (Friday) at 1:00 p.m. A talk on Enumeration Reducibility: 60 years of investigation will be delivered by Hristo Ganchev (Faculty of Mathematics and Informatics of the Sofia University). Abstract. We will make an overview of the main results and problems in Еnumeration reducibility – one of the two main reducibilities used to compare the complexity of the information content in sets of natural numbers.   The seminar will be held via Zoom and everyone can join via the link: https://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 Topic: Онлайн семинар на секция "Алгебра и логика" Time: Feb 26, 2021 01:00 PM Sofia Meeting ID: 851 3737 5021 Passcode: 035647   Algebra and Logic Department, IMI-BAS http://www.math.bas.bg/algebra/seminarAiL/ [...]

An online session of the Algebra and Logic Seminar will be held on February 19, 2021 (Friday) at 1:00 p.m. A talk on Identities in Prime Rings will be delivered by Jose Brox (Centre for Mathematics of the University of Coimbra, Portugal). Abstract. Given a ring, a generalized polynomial identity (GPI) is a polynomial identity in which the coefficients can be taken from the ring. Prime rings are a class of rings very well suited to manage problems related to identities, as for example those coming from Herstein's theory, which is the study of nonassociative objects and structures arising from associative rings. After a motivating introduction to prime rings, with some examples from Herstein's theory, I will show the usefulness of Martindale's lemma, the [...]

An online session of the Algebra and Logic Seminar will be held on February 12, 2021 (Friday) at 4:00 p.m. A talk on On the Newton polytope of a Jacobian pair will be delivered by Leonid Makar-Limanov (Wayne State University, Detroit, USA and Weizmann Institute of Science, Rehovot, Israel). The seminar will be held via Zoom and everyone can join via the link: https://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 Topic: Онлайн семинар на секция "Алгебра и логика" Time: Feb 12, 2021 04:00 PM Sofia Meeting ID: 851 3737 5021 Passcode: 035647 Abstract.First, I remind what is the Jacobian Conjecture and talk about some history related to it. Then I'll briefly explain what is the “shape” of a minimal counterexample to the conjecture. After that the Newton polytope related to [...]

An online session of the Algebra and Logic Seminar will be held on February 5, 2021 (Friday) at 1:00 p.m. A talk on Reduction Calculus of Type-Theory of Acyclic Algorithms, II will be delivered by Roussanka Loukanova, IMI - BAS. This is a continuation of the talk given on January 29, 2021. The seminar will be held via Zoom and everyone can join via the link: https://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09  Topic: Онлайн семинар на секция "Алгебра и логика" Time: Feb 05, 2021 01:00 PM Sofia Meeting ID: 851 3737 5021 Passcode: 035647 Abstract. In 1989, Moschovakis [1] initiated a new theory of the mathematical notion of algorithm, within untyped, full recursion. In 2006, Moschovakis [2] introduced the formal language of Type-Theory of Recursion (TTR), which models the [...]

An online session of the Algebra and Logic Seminar will be held on January 29, 2021 (Friday) at 1:00 p.m. A talk on Reduction Calculus of Type-Theory of Acyclic Algorithms will be delivered by Roussanka Loukanova, IMI - BAS. The seminar will be held via Zoom and everyone can join via the link:https://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09  Topic: Онлайн семинар на секция "Алгебра и логика" Time: Jan 29, 2021 01:00 PM Sofia Meeting ID: 851 3737 5021 Passcode: 035647 Abstract. In 1989, Moschovakis [1] initiated a new theory of the mathematical notion of algorithm, within untyped, full recursion. In 2006, Moschovakis [2] introduced the formal language of Type-Theory of Recursion (TTR), which models the notion of algorithm and concepts of meaning in typed semantic structures. The focus of [...]

An online session of the Algebra and Logic Seminar will be held on January 8, 2021 (Friday) at 1:00 p.m. A talk on Derivations in matrix semirings will be delivered by Dimitrinka Vladeva (University of Forestry, Sofia). Abstract. The seminar will be held via Zoom and everyone can join via the link: https://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 Topic: Онлайн семинар на секция "Алгебра и логика" Time: Jan 08, 2021 01:00 PM Sofia Meeting ID: 851 3737 5021 Passcode: 035647 Algebra and Logic Department, IMI-BAS http://www.math.bas.bg/algebra/seminarAiL/