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BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20240607T123000
DTEND;TZID=Europe/Sofia:20240607T140000
DTSTAMP:20260405T143520
CREATED:20240605T211422Z
LAST-MODIFIED:20240605T211422Z
UID:16409-1717763400-1717768800@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 7 юни 2024 г. (петък) от 12:30 часа в зала 503 на ИМИ\nще се проведе присъствено заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nSome Properties and Applications of Kloosterman Sums on Finite Fields\nще изнесе \nЛюбомир Борисов\, ИМИ – БАН. \nАбстракт \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%b0-114/
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:20240412T130000
DTEND;TZID=Europe/Sofia:20240412T143000
DTSTAMP:20260405T143520
CREATED:20240409T201342Z
LAST-MODIFIED:20240409T201619Z
UID:16175-1712926800-1712932200@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 12 април 2024 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nOn an Aspect of Second Quantum Revolution\nще изнесе \nВалентин Илиев\, ИМИ – БАН. \nАбстракт. The 2022 Nobel Prize in Physics has been awarded to Alain Aspect\, John Clauser\, and Anton Zeilinger for their work in Quantum Theory. Mass media called this event part of second quantum revolution which includes mainly quantum computing and other super-technologies. Here we discuss Alain Aspect’s version of Einstein-Podolsky-Rosen thought experiment and show that there exists an internal dependence of the simultaneous measurements made by the two pairs of linear polarizers operated in each leg of the apparatus during this experiment. The corresponding Shannon-Kolmogorov information flow (or\, noise?) linking a polarizer from one leg to a polarizer from the other leg is proportional to the absolute value of this function of dependence. It turns out that if Bell’s inequality is violated\, then the experiment performed at one leg is informationally dependent on the experiment at the other leg. \nЛинк към Zoom-стаята на семинара:\nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \n\n\n\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%b0-113/
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:20240329T130000
DTEND;TZID=Europe/Sofia:20240329T143000
DTSTAMP:20260405T143520
CREATED:20240326T074049Z
LAST-MODIFIED:20240326T074049Z
UID:16107-1711717200-1711722600@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 29 март 2024 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nGeneralized Definability of Discrete Time Interval-based Temporal Connectives\nще изнесе \nДимитър Гелев\, ИМИ – БАН. \nАбстракт. 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 a first-order definition\, a star-free ITLNL defining formula for #(A1\,…\,Am) can be produced that is built from the past\, future and introspective formulas appearing in some separated equivalents of the operands A1\,…\,Am. The proof is based in an interval-based analogue of Gabbay’s separation theorem about PLTL that was previously established about ITLNL by the neighbourhood modalities by me and Moszkowski and have now used to prove the expressive completeness of ITLNL. As a side result I have come upon new proofs of expressive completeness and temporal separation for ITLNL’s star-free subset that I will briefly discuss too. \nЛинк към Zoom-стаята на семинара:\nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \n\n\n\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%b0-112/
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:20240322T130000
DTEND;TZID=Europe/Sofia:20240322T143000
DTSTAMP:20260405T143520
CREATED:20240315T082836Z
LAST-MODIFIED:20240315T082836Z
UID:16071-1711112400-1711117800@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 22 март 2024 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nOn the uniqueness of maximal solvable extensions of nilpotent Lie algebras\nще изнесе \nBakhrom A. Omirov (Harbin Institute of Technologies\, Harbin\, China and Romanovskiy Institute of Mathematics\, Uzbekistan Academy of Sciences\, Uzbekistan). \nАбстракт. 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. \nЛинк към Zoom-стаята на семинара:\nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \n\n\n\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%b0-111/
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:20240223T130000
DTEND;TZID=Europe/Sofia:20240223T143000
DTSTAMP:20260405T143520
CREATED:20240216T131821Z
LAST-MODIFIED:20240216T131821Z
UID:15974-1708693200-1708698600@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 23 февруари 2024 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nInvariant subalgebras of the rational Cherednik algebra\nще изнесе \nNiall Hird (University of Glasgow\, UK). \nАбстракт. 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 rational Cherednik algebra under the same groups. These subalgebras arise naturally in the study of rational Cherednik algebras\, one of which is the Dunkl angular momentum algebra and the other is generated by all degree zero elements. \nЛинк към Zoom-стаята на семинара:\nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \n\n\n\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%b0-110/
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:20240108T130000
DTEND;TZID=Europe/Sofia:20240108T143000
DTSTAMP:20260405T143520
CREATED:20240104T180400Z
LAST-MODIFIED:20240104T180400Z
UID:15799-1704718800-1704724200@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 8 януари 2024 г. (понеделник) от 13:00 часа в зала 578 на ИМИ-БАН и онлайн чрез платформата zoom ще се проведе хибридно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nOn the exceptional series and its siblings\nще изнесе \nBruce Westbury (retired from University of Warwick\, UK). \nАбстракт. The exceptional series is the following series of eight simple Lie algebras: \nA1\, A2\, G2\, D4\, F4\, E6\, E7\, E8 \nConsider 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 of eight points on a line. Then the values of the quadratic Casimir are linear functions of this parameter and the dimensions are rational functions of this parameter. \nThe exceptional series is one row in the Freudenthal magic square and all the preferred representations for each row also have analogous common structure. These series are lines. I will give a broad context for this common structure. \nThere is a plane which contains the first and fourth rows of the magic square and a three-dimensional space which contains the Vogel plane. \nЛинк към Zoom-стаята на семинара:\nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \n\n\n\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%b0-109/
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:20231201T130000
DTEND;TZID=Europe/Sofia:20231201T143000
DTSTAMP:20260405T143520
CREATED:20231129T101726Z
LAST-MODIFIED:20231129T104247Z
UID:15526-1701435600-1701441000@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 1 декември 2023 г. (петък) от 13:00 часа ще се проведе хибридно заседание (присъствено в зала 578 на ИМИ-БАН и онлайн чрез платформата zoom) на семинара по „Алгебра и логика”. \nДоклад на тема: \nCharacterization of Ideals of Q-algebras Related to its G-part\nще изнесе \nдоц. Йорг Копиц\, ИМИ – БАН. \nАбстракт. 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 \(G(X)=X\)\, which is only possible if \(|X|=2^{k}\) (\(k\in \mathbb{N}\)). \nЛинк към Zoom-стаята на семинара:\nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \n\n\n\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%b0-108/
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:20231124T130000
DTEND;TZID=Europe/Sofia:20231124T150000
DTSTAMP:20260405T143520
CREATED:20231120T160634Z
LAST-MODIFIED:20231121T083451Z
UID:15474-1700830800-1700838000@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 24 ноември 2023 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”\, на който ще бъдат изнесени два доклада. \nОт 13:00 ч. Димитринка Владева (ИМИ-БАН) ще изнесе доклад на тема \nCatalan numbers and additively idempotent semirings\nОт 14:00 ч. Русанка Луканова (ИМИ-БАН) ще изнесе доклад на тема \nSemantics of Propositional Attitudes in Type-Theory of Algorithms\n  \nЗаглавие: Catalan numbers and additively idempotent semirings \nАбстракт. 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\, real polynomials and so on. We show applications of Catalan numbers in some additively idempotent semirings which appeared in my results in 5 papers published between 2011 and 2023. \nThe set of nilpotent endomorphisms in the endomorphism semiring of a finite chain is a semiring of order (n – 1)th Catalan number and is an ideal in another semiring of order n th Catalan number. The semiring of k th nilpotent endomorphisms\, where 0 ≤ k ≤ n – 1 is of order a product of two Catalan numbers. By complex products of Catalan numbers we describe the roots of arbitrary idempotent of the endomorphism semiring of a finite chain.\nIn an additively idempotent semiring which is a generalization of the endomorphism semiring of a finite chain considered as a simplex we prove that the subsimplex of nilpotent elements is of order (n – 1) th Catalan number and it is closed under derivations which are projections of the simplex to some simplices.\nIn the last paper\, 2023\, we prove that an additively idempotent semiring which is an S0-semialgebra\, where S0 is a commutative additively idempotent semiring\, and with a finite basis of a special type is isomorphic to a matrix semiring. As a consequence we obtain two different semirings of upper triangular matrices over the Boolean semiring\, which are of order (n + 1) th Catalan number.\n\n\nЗаглавие: Semantics of Propositional Attitudes in Type-Theory of Algorithms \nАбстракт. Natural language (NL) is notorious for various kinds of ambiguities.  Among the most difficult ones\, for computational handling of NL\, are expressions with multiple occurrences of quantifiers\, which contribute to quantifier scope ambiguities. Far more difficult for computational linguistics are NL expressions having occurrences of so-called attitude components designating knowledge\, believes\, statements\, and similar semantic information. \nOften\, the syntactic complement of an attitude lexeme is a sentential expression. The sentential complement may have subexpressions that designate semantic information belonging to varying scopes.  Depending on context\, some components can be semantic parts of the attitudinal information\, which is in the scope of the propositional attitude\, or external to it. \nThe first formal representation of NL attitudes was by Montague\, 1973\, along with the quantifier scope ambiguities\, by the notions of extension and intension\, and using extra-syntactic disambiguation of NL expressions. That approach\, while unsatisfactory in important aspects\, was adopted and adapted by some variants of Montague grammars\, for specific purposes. The problem has been largely open\, due to its purely semantic nature and computational difficulties\, without direct syntactic appearance. \nThe semantic phenomena of attitudes include statements in natural language\, including in the domains of mathematical texts and proofs. \nIn this presentation of a recent paper\, I extend the type-theory of algorithms\, to cover algorithmic semantics of some of the major attitude expressions and their semantic underspecification. I provide reduction calculus for deriving semantic specifications in contexts. \n  \n\nЛинк към Zoom-стаята на семинара:\nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \n\n\n\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%b0-107/
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:20231117T130000
DTEND;TZID=Europe/Sofia:20231117T143000
DTSTAMP:20260405T143520
CREATED:20231114T182803Z
LAST-MODIFIED:20231114T182803Z
UID:15410-1700226000-1700231400@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 17 ноември 2023 г. (петък) от 13:00 часа ще се проведе хибридно заседание (присъствено в зала 578 на ИМИ-БАН и онлайн чрез платформата zoom) на семинара по „Алгебра и логика”. \nДоклад на тема: \nNoncommutative invariants of dihedral groups\nще изнесе \nБоян Костадинов\, ИМИ – БАН. \nАбстракт. 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 ideal as a module of the algebra of the invariants in the polynomial algebra in two variables. In both associative and Lie cases we compute the Hilbert series of the algebras of invariants.\nThe results are obtained jointly with Vesselin Drensky. \nЛинк към Zoom-стаята на семинара:\nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \n\n\n\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%b0-106/
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:20231110T130000
DTEND;TZID=Europe/Sofia:20231110T143000
DTSTAMP:20260405T143520
CREATED:20231106T101108Z
LAST-MODIFIED:20231106T101108Z
UID:15351-1699621200-1699626600@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 10 ноември 2023 г. (петък) от 13:00 часа ще се проведе хибридно заседание (присъствено в зала 578 на ИМИ-БАН и онлайн чрез платформата zoom) на семинара по „Алгебра и логика”. \nДоклад на тема: \nTransfinite version of the Mittag-Leffler condition for the vanishing of the derived limit\nще изнесе \nMishel Carelli (Technion – Israel Institute of Technology\, Israel). \nАбстракт. 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 such that lim S = lim¹S = 0 is the least class of inverse sequences containing the trivial inverse sequence and closed with respect to small limits and a certain type of extensions. \nЛинк към Zoom-стаята на семинара:\nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \n\n\n\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%b0-105/
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:20231103T130000
DTEND;TZID=Europe/Sofia:20231103T143000
DTSTAMP:20260405T143520
CREATED:20231026T161427Z
LAST-MODIFIED:20231026T161427Z
UID:15287-1699016400-1699021800@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 3 ноември 2023 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nA Reduction of Temporary Coalitions in Infinite Multiplayer Games\nще изнесе Димитър Гелев. \nАбстракт. 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 the analysis of games with temporary coalitions. \n\nЛинк към Zoom-стаята на семинара:\nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \n\n\n\n\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%b0-104/
LOCATION:Zoom
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:20231020T130000
DTEND;TZID=Europe/Sofia:20231020T143000
DTSTAMP:20260405T143520
CREATED:20231016T064735Z
LAST-MODIFIED:20231016T064735Z
UID:15193-1697806800-1697812200@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 20 октомври 2023 г. (петък) от 13:00 часа ще се проведе хибридно (присъствено в зала 578 на ИМИ-БАН и онлайн чрез платформата zoom) заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nPrime numbers and random walks in a square grid\nще изнесе Alberto Fraile (Czech Technical University in Prague\, Czech Republic). \nСъвместна работа с Osame Kinouchi\, Prashant Dwivedi\, Roberto Martínez\, Theophanes E. Raptis и Daniel Fernández \nАбстракт. 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 are playing a fundamental role in unveiling some of the most intriguing features of prime numbers. In this work\, we define an algorithm for a deterministic walk through a two-dimensional grid that we refer to as Prime Walk (PW). The walk is constructed from a sequence of steps dictated by and dependent on the sequence of last digits of the primes. Despite the apparent randomness of this generating sequence\, the resulting structure – both in 2d and 3d – created by the algorithm presents remarkable properties and regularities in its pattern that we proceed to analyze in detail [1]. \n[1] A. Fraile\, O. Kinouchi\, P. Dwivedi\, R. Martínez\, T. E. Raptis\, D. Fernández\, Prime numbers and random walks in a square grid\, Phys. Rev. E 104 (5)\, 054114-054120 (2021). \n\nЛинк към Zoom-стаята на семинара:\nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \n\n\n\n\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%b0-103/
LOCATION:Zoom
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:20231013T130000
DTEND;TZID=Europe/Sofia:20231013T143000
DTSTAMP:20260405T143520
CREATED:20231006T132150Z
LAST-MODIFIED:20231006T132150Z
UID:15092-1697202000-1697207400@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 13 октомври 2023 г. (петък) от 13:00 часа ще се проведе хибридно (присъствено в зала 578 на ИМИ-БАН и онлайн чрез платформата zoom) заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nEmmy Noether’s Theorem on the Finite Generation of the Algebra of Invariants\nще изнесе Марин Генов (ИМИ – БАН). \nАбстракт. 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]. \n\nЛинк към Zoom-стаята на семинара:\nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \n\n\n\n\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%b0-102/
LOCATION:Zoom
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:20230929T130000
DTEND;TZID=Europe/Sofia:20230929T143000
DTSTAMP:20260405T143520
CREATED:20230925T142821Z
LAST-MODIFIED:20230925T145459Z
UID:15043-1695992400-1695997800@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 29 септември 2023 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nReset Controller Synthesis\nще изнесе Naijun Zhan (Institute of Software Chinese Academy of Sciences (ISCAS)\, China). \nАбстракт. 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 talk\, I will summarize our recent work on the reset controller synthesis for HS. The basic idea is to reduce the problem of guaranteeing safety and liveness properties to differential invariant generation and generalized reach-avoid problems. For polynomial hybrid systems\, those problems can be solved by further reduced to convex optimizations. \nMoreover\, for reality\, we discuss this issue in the context of time-delay\, as time delay is inevitable in practice. So\, we investigate the reset controller synthesis problem for delay hybrid systems (dHS).\n\nСеминарът ще се проведе посредством платформата Zoom и всеки желаещ може да се присъедини като последва линка:\nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \n\nTopic: Онлайн семинар на секция “Алгебра и логика”\nTime: Sep 29\, 2023 01:00 PM Sofia\nMeeting ID: 851 3737 5021\nPasscode: 035647\n\n\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%b0-101/
LOCATION:Zoom
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:20230926T140000
DTEND;TZID=Europe/Sofia:20230926T153000
DTSTAMP:20260405T143520
CREATED:20230917T153449Z
LAST-MODIFIED:20230918T115002Z
UID:14963-1695736800-1695742200@math.bas.bg
SUMMARY:Съвместно заседание на общия семинар на секция „Анализ\, геометрия и топология“ и семинара на секция „Алгебра и логика”
DESCRIPTION:На 26 септември 2023 г. от 14:00 часа в зала 478 на ИМИ-БАН\nще се проведе съвместно заседание на\nобщия семинар на секция „Анализ\, геометрия и топология“\nи семинара на секция „Алгебра и логика”. \nДоклад на тема \nBurau Representation and Application to Reducibility and Exchangeability of Braids\nще изнесе Alexander Stоimenov\, Dongguk University\, Republic of Korea. \nАбстракт. 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.
URL:https://math.bas.bg/event/%d1%81%d1%8a%d0%b2%d0%bc%d0%b5%d1%81%d1%82%d0%bd%d0%be-%d0%b7%d0%b0%d1%81%d0%b5%d0%b4%d0%b0%d0%bd%d0%b8%d0%b5-%d0%bd%d0%b0-%d0%be%d0%b1%d1%89%d0%b8%d1%8f-%d1%81%d0%b5%d0%bc%d0%b8%d0%bd%d0%b0%d1%80/
LOCATION:Институт по математика и информатика – БАН\, Block 8\, 1113 БАН IV км.\, София\, Bulgaria
CATEGORIES:Работен семинар,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
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20230623T130000
DTEND;TZID=Europe/Sofia:20230623T143000
DTSTAMP:20260405T143520
CREATED:20230620T103815Z
LAST-MODIFIED:20230620T103836Z
UID:14584-1687525200-1687530600@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 23 юни 2023 г. (петък) от 13:00 часа в зала 578 на ИМИ – БАН ще се проведе присъствено заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nDistinctness of the “Lifted” Kloosterman Sums over the Prime Field Fp\nще изнесе Любомир Борисов. \n\nАбстракт \n  \n\n\nОт секция „Алгебра и логика” на ИМИ – БАН\n\nhttp://www.math.bas.bg/algebra/seminarAiL/\n============================== =====================
URL:https://math.bas.bg/event/copy-%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/
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:20230616T130000
DTEND;TZID=Europe/Sofia:20230616T143000
DTSTAMP:20260405T143520
CREATED:20230612T095945Z
LAST-MODIFIED:20230612T095945Z
UID:14552-1686920400-1686925800@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 16 юни 2023 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nPolynomial identities in Novikov algebras\nще изнесе Nurlan Ismailov (Astana IT University and Suleyman Demirel University\, Kaskelen\, Kazakhstan)\n(Joint work with V. Dotsenko and U. Umirbaev). \n\nАбстракт.The talk is devoted to Novikov algebras satisfying nontrivial identities. We show that a Novikov algebra over a field of zero characteristic that satisfies a nontrivial identity satisfies some unexpected “universal” identities\, in particular\, right associator nilpotence\, and right nilpotence of the commutator ideal. This\, in particular\, implies that a Novikov algebra over a field of zero characteristic satisfies a nontrivial identity if and only if it is Lie-solvable. We also establish that any system of identities of Novikov algebras over a field of zero characteristic follows from finitely many of them\, and that the same holds over any field for multilinear Novikov identities. Some analogous simpler statements are also proved for commutative differential algebras. \n  \n\n\nСеминарът ще се проведе посредством платформата Zoom и всеки желаещ може да се присъедини като последва линка: \nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \nTopic: Онлайн семинар на секция “Алгебра и логика”\nTime: Jun 16\, 2023 01:00 PM Sofia\nMeeting ID: 851 3737 5021\nPasscode: 035647 \n\n\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%b0-100/
LOCATION:Zoom
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:20230609T130000
DTEND;TZID=Europe/Sofia:20230609T143000
DTSTAMP:20260405T143520
CREATED:20230601T070646Z
LAST-MODIFIED:20230601T070646Z
UID:14455-1686315600-1686321000@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 9 юни 2023 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nOld and new aspects of the Poincaré-Birkhoff-Witt theorem\nще изнесе Vladimir Dotsenko (Institute for Advanced Mathematical Research (IRMA)\, University of Strasbourg and CNRS\, France). \n\nАбстракт. The Poincaré-Birkhoff-Witt theorem on universal enveloping algebras of Lie algebras is a fundamental result in many areas of mathematics: from differential geometry and representation theory to homological algebra and deformation quantization. I shall give a short overview of that result and some of its proofs that emerged in about 120 years since Poincaré published a paper about it\, and outline a new proof which perhaps captures its category-theoretic essence in the best way possible. The talk is based on a joint work with Pedro Tamaroff. \n  \n\n\nСеминарът ще се проведе посредством платформата Zoom и всеки желаещ може да се присъедини като последва линка: \nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \nTopic: Онлайн семинар на секция “Алгебра и логика”\nTime: Jun 09\, 2023 01:00 PM Sofia\nMeeting ID: 851 3737 5021\nPasscode: 035647 \n\n\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%b0-99/
LOCATION:Zoom
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:20230505T130000
DTEND;TZID=Europe/Sofia:20230505T143000
DTSTAMP:20260405T143520
CREATED:20230502T134141Z
LAST-MODIFIED:20230502T134141Z
UID:14286-1683291600-1683297000@math.bas.bg
SUMMARY:Семинар "Алгебра и логика" - встъпителна лекция на проф. Й. Копиц
DESCRIPTION:На 5 май 2023 г. (петък) от 13:00 часа ще се проведе встъпителна академична лекция на \nпроф. Йорг Копиц \nна тема: \nAlgebraic Properties of Transformation Semigroups\nАбстракт. Each semigroup is isomorphic to a semigroup of transformations on a suitable set (Cayley Theorem for semigroups). If we know generating sets of minimal size (rank) of a finitely generating semigroup then we have important information about the algebraic structure of the semigroup itself. For not finitely generated semigroups\, we consider relative generating sets of minimal size modulo a given subset of the semigroup (relative rank). We determine the (relative) rank of several semigroups of transformations. These semigroups were already considered by other authors. \nBy the study of congruences on a semigroup\, we obtain further important information about the structure of a given semigroup\, which are related to its ideals. We discuss the congruence lattice of an infinite transformation semigroup as well of the maximal nilpotent subsemigroups of the Catalan Monoid.\n\n\nСеминарът ще се проведе посредством платформата Zoom и всеки желаещ може да се присъедини като последва линка: \n\n\nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \nTopic: Онлайн семинар на секция “Алгебра и логика”\nTime: May 05\, 2023 01:00 PM Sofia\nMeeting ID: 851 3737 5021\nPasscode: 035647 \n\n\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-%d0%b2%d1%81%d1%82%d1%8a%d0%bf%d0%b8%d1%82%d0%b5%d0%bb%d0%bd/
LOCATION:Zoom
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:20230407T130000
DTEND;TZID=Europe/Sofia:20230407T143000
DTSTAMP:20260405T143520
CREATED:20230403T124532Z
LAST-MODIFIED:20230403T124532Z
UID:14170-1680872400-1680877800@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 7 април 2023 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nExact values of exponential Følner functions and the Coulhon and Saloff-Coste inequality\nще изнесе Богдан Станков (Institut Camille Jordan\, Université Claude Bernard Lyon 1\, France). \n\nАбстракт. For infinite groups\, the Følner criterion states that a group is amenable if and only if the isoperimetric constant of its Cayley graph is 0. In that case\, a more precise description of its isoperimetric profile is given by the Følner function. It depends on the choice of generating set\, but different functions on the same group are asymptotically equivalent. Multiple results have been obtained on Følner functions\, but only up to asymptotic equivalence class. In this talk\, we will consider fixed generating sets and obtain (to our knowledge) the first results (outside of virtually nilpotent groups) on the exact values of Følner functions – on wreath products ℤ ≀ D for a finite group D. We will consider possible applications. In particular\, we’re interested in the connections with the Coulhon and Saloff-Coste inequality. That inequality gives a lower bound on the Følner function. In joint work with Christophe Pittet\, for groups of exponential growth we obtain a description of the optimal multiplicative constant in the Coulhon and Saloff-Coste inequality. We show that the optimal value over all groups of this constant is between 1 and 2. \n  \n\n\nСеминарът ще се проведе посредством платформата Zoom и всеки желаещ може да се присъедини като последва линка: \nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \nTopic: Онлайн семинар на секция “Алгебра и логика”\nTime: Apr 07\, 2023 01:00 PM Sofia\nMeeting ID: 851 3737 5021\nPasscode: 035647 \n\n\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%b0-98/
LOCATION:Zoom
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:20230224T130000
DTEND;TZID=Europe/Sofia:20230224T143000
DTSTAMP:20260405T143520
CREATED:20230220T100158Z
LAST-MODIFIED:20230220T100158Z
UID:13930-1677243600-1677249000@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 24 февруари 2023 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nReal Hamiltonian forms of affine Toda field theories: spectral aspects\nще изнесе Владимир Герджиков (съвместна работа с Г. Г. Граховски и А. А. Стефанов). \n\nАбстракт. \nThe talk is devoted to real Hamiltonian forms of 2-dimensional Toda field theories related to exceptional simple Lie algebras\, and to the spectral theory of the associated Lax operators. Real Hamiltonian forms are a special type of reductions of Hamiltonian systems\, similar to real forms of semisimple Lie algebras. The real Hamiltonian forms of affine Toda field theories related to exceptional complex untwisted affine Kac – Moody algebras are studied. Along with the associated Lax representations\, we also formulate the relevant Riemann – Hilbert problems and derive the minimal sets of scattering data that uniquely determine the scattering matrices and the potentials of the Lax operators. \nReferences\n[1] V. S. Gerdjikov\, G. G. Grahovski\, A. A. Stefanov. Real Hamiltonian forms of affine Toda field theories: spectral aspects. Theoretical and Mathematical Physics\, 212(2): 1053-1072 (2022); arXiv:2205.03844v1 [nlin.SI] \n  \n\n\nСеминарът ще се проведе посредством платформата Zoom и всеки желаещ може да се присъедини като последва линка: \nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \nTopic: Онлайн семинар на секция “Алгебра и логика”\nTime: Feb 24\, 2023 01:00 PM Sofia\nMeeting ID: 851 3737 5021\nPasscode: 035647 \n\n\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%b0-97/
LOCATION:Zoom
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:20230217T130000
DTEND;TZID=Europe/Sofia:20230217T143000
DTSTAMP:20260405T143520
CREATED:20230214T123832Z
LAST-MODIFIED:20230214T123832Z
UID:13877-1676638800-1676644200@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 17 февруари 2023 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nInvariant theory for reductive subgroups of reductive groups\nще изнесе Валдемар Цанов (ИМИ-БАН). \n\nАбстракт. Let H ⸦ G be an embedding of connected complex reductive linear algebraic groups. A classical question with several important interpretations is: which irreducible G-modules contain nonzero H-invariant vectors? An approach based on the Geometric Invariant Theory of Hilbert-Mumford was developed in works of Heckman\, Berenstein-Sjamaar\, Belkale-Kumar and Ressayre\, culminating in a description of the generalized Littlewood-Richadson cone – the convex hull of set of the highest weights of the G-modules containing H-invariants. The discrepancy between the convex hull and the actual set of weights presents the so-called saturation problem\, famously solved by Knutson and Tao for diagonal embeddings of GL_n\, and widely open in general. Ressayre’s description of the cone demands extensive calculations even in relatively tame cases\, which makes applications difficult. Further development of the structure theory seems desirable.\nIn this talk\, based on joint works with Seppänen and Staneva\, I will present some structural properties of generalized Littlewood-Richardson cones\, allowing to partition the subgroups of a given G into types according to the properties of the cones. We derive a new numerical invariant of reductive groups\, and use it to show that for “generic” subgroups the cone fills the entire Weyl chamber of G. This greatly reduces the difficulty of the saturation problem and allows it to be solved for some new cases\, e.g. SL_2-subgroups of classical groups. \n  \n\n\nСеминарът ще се проведе посредством платформата Zoom и всеки желаещ може да се присъедини като последва линка: \nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \nTopic: Онлайн семинар на секция “Алгебра и логика”\nTime: Feb 17\, 2023 01:00 PM Sofia\nMeeting ID: 851 3737 5021\nPasscode: 035647 \n\n\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%b0-96/
LOCATION:Zoom
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:20230210T130000
DTEND;TZID=Europe/Sofia:20230210T143000
DTSTAMP:20260405T143520
CREATED:20230207T091426Z
LAST-MODIFIED:20230207T091426Z
UID:13780-1676034000-1676039400@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 10 февруари 2023 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nA New Approach to the Characteristic Polynomial of a Random Unitary Matrix\nще изнесе Yacine Barhoumi-Andréani (Ruhr-Universität Bochum\, Germany). \n\nАбстракт. The characteristic polynomial of a random (Haar-distributed) unitary matrix is considered as an interesting toy model for the probabilistic study of the Riemann Zeta function. We will recall the history of the topic starting with the Montgommery-Dyson correspondance\, the Keating-Snaith moments conjecture and some recent developments on other functionals. We will then give a conceptual comparison of some of the techniques used in the field and a zoo of results one can achieve\, with a particular focus on a recent technique that allows to rederive all the results in a unified way using symmetric function theory and local Central Limit Theorems. \n  \n\n\nСеминарът ще се проведе посредством платформата Zoom и всеки желаещ може да се присъедини като последва линка: \nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \nTopic: Онлайн семинар на секция “Алгебра и логика”\nTime: Feb 10\, 2023 01:00 PM Sofia\nMeeting ID: 851 3737 5021\nPasscode: 035647 \n\n\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%b0-95/
LOCATION:Zoom
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:20230113T130000
DTEND;TZID=Europe/Sofia:20230113T143000
DTSTAMP:20260405T143520
CREATED:20230106T122006Z
LAST-MODIFIED:20230106T122006Z
UID:13582-1673614800-1673620200@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 13 януари 2023 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nОтчет за работата по докторантурата на Димитър Добрев на тема “Изкуствен интелект – дефиниция\, реализация и последствия”\nще изнесе Димитър Добрев. \n\nАбстракт. В основата на дисертацията са езиците за описание на светове. Тези езици описват класове от функции като изчислимите функции и някои разширения на този клас. При помощта на език за описание на светове дефинираме ИИ и създаваме програма\, която твърдим\, че удовлетворява тази дефиниция. Тази програма е чисто теоретична\, защото тя е толкова неефективна\, че на практика е неизползваема. Изказваме предположението\, че с подходящ език за описание на светове може да се направи ефективна програма\, която да удовлетвори дефиницията на ИИ и описваме един такъв език. В края на дисертацията се разглеждат някои философски въпроси свързани с последствията от създаването на ИИ. Например задаваме въпроса „Трябва ли технологията ИИ да бъде общодостъпна?“. Отговорът\, който даваме\, е\, че това е опасна технология и не трябва да се разпространява неконтролирано. \n  \n\n\nСеминарът ще се проведе посредством платформата Zoom и всеки желаещ може да се присъедини като последва линка: \nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \nTopic: Онлайн семинар на секция “Алгебра и логика”\nTime: Jan 13\, 2023 01:00 PM Sofia\nMeeting ID: 851 3737 5021\nPasscode: 035647 \n\n\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%b0-94/
LOCATION:Zoom
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:20221209T130000
DTEND;TZID=Europe/Sofia:20221209T143000
DTSTAMP:20260405T143520
CREATED:20221203T124907Z
LAST-MODIFIED:20221203T124907Z
UID:13375-1670590800-1670596200@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 9 декември 2022 г. (петък) ще се проведе дистанционно заседание на семинара по „Алгебра и логика”\, на което ще бъдат изнесени два доклада. \nОт 13:00 до 14:00 часа доклад на тема: \nAdS/CFT съответствие\, Метрополис-Хастингс алгортъм и GAN невронни мрежи\nще изнесе Веселин Филев. \n\nАбстракт. Ще докладвам за скорошна публикация по конструира-нето на D0/D4 пространство-време. Ще дискутирам значението на това изследване в AdS/CFT съответствието и симулирането на матричния модел на Беркуз-Дъглас. Във втората част на доклада ще дискутирам алгоритъма на Метрополис-Хастингс и ще докладвам възможни приложения на GAN невронни мрежи в симулацията на трудни в изчислително отношение матрични модели. \nОт 14:00 до 14:45 часа доклад на тема: \nHitchin base: Seiberg-Witten differentials and their derivatives\nще изнесе Петър Далаков (АУБ и ИМИ-БАН). \nАбстракт. We consider a variation of Hodge structures of weight 1 and a Seiberg-Witten differential on the Hitchin base and discuss an explicit formula its Gauss-Manin derivative. \n  \n\n\nСеминарът ще се проведе посредством платформата Zoom и всеки желаещ може да се присъедини като последва линка: \nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \nTopic: Онлайн семинар на секция “Алгебра и логика”\nTime: Dec 09\, 2022 01:00 PM Sofia\nMeeting ID: 851 3737 5021\nPasscode: 035647 \n\n\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%b0-93/
LOCATION:Zoom
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:20221202T130000
DTEND;TZID=Europe/Sofia:20221202T143000
DTSTAMP:20260405T143520
CREATED:20221130T095341Z
LAST-MODIFIED:20221130T095341Z
UID:13338-1669986000-1669991400@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 2 декември 2022 г. (петък) от 13:00 ч. ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nDerivations of upper triangular matrix rings\nvs\nDerivations of upper triangular matrix semirings \nще изнесе Димитринка Владева. \nАбстракт. The motivation for this talk is the problem how to represent a derivation of a matrix ring and of an additively idempotent matrix semiring as a sum of well-known derivations. \nThe results of two of my articles\, published in 2022\, will be compared and we will draw conclusions about the advantages and disadvantages of these results.\nWe begin by considering the nature of derivations of triangular matrices over an additively idempotent semiring R generated by left and right semicentral idempotents. Then we construct a semiring D of these derivations and find a basis of D\, considered as an R-semimodule. The main result of the first article states that an arbitrary derivation of UTMn(R) (the semiring of upper triangular matrices over an additively idempotent semiring R) is a linear combination of a derivations from the basis of R-semimodule D. When R is an associative ring with identity and UTMn(R) is the ring of upper triangular n x n matrices over R we propose a basis of an additive group D of derivations of UTM_n(R) consisting of derivations δ_i such that δ_i(A) = [e_ii\,A]\, where A ∈UTM_n(R) and e_ii are diagonal matrix units for i = 2\, …\, n. The main result states that if D is an arbitrary derivation of the ring UTM_n(R) and A ∈UTM_n(R)\, then there are matrices\, such that the derivative D(A) is a linear combination of the values of derivations δ_i ∈D\, i = 2\, …\, n\, of these matrices with coefficients the entries of the matrix A.\n  \n\n\nСеминарът ще се проведе посредством платформата Zoom и всеки желаещ може да се присъедини като последва линка: \nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \nTopic: Онлайн семинар на секция “Алгебра и логика”\nTime: Dec 02\, 2022 01:00 PM Sofia\nMeeting ID: 851 3737 5021\nPasscode: 035647 \n\n\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%b0-92/
LOCATION:Zoom
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:20221125T130000
DTEND;TZID=Europe/Sofia:20221125T143000
DTSTAMP:20260405T143520
CREATED:20221122T093807Z
LAST-MODIFIED:20221122T093807Z
UID:13319-1669381200-1669386600@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 25 ноември 2022 г. (петък) от 13:00 ч. ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nLogic Operators and Quantifiers in Type-Theory of Algorithms\nще изнесе Русанка Луканова (ИМИ – БАН). \n\nАбстракт. I shall introduce an extension of Moschovakis Type-Theory of Algorithms (LR) and its reduction calculus\, by adding logic operators and quantifiers. The LR has two kinds of terms of formulae\, for designating state-independent and state-dependent propositions and predications. The logic operators include conjunction\, disjunction\, implication\, and negation. I extend the formal language of LR by state-dependent quantifiers\, for enhancing the standard quantifiers of predicate logic. I provide an extended reduction calculus of the Type-Theory of Acyclic Algorithms\, for reductions of LR terms to their canonical forms. \n  \n\n\nСеминарът ще се проведе посредством платформата Zoom и всеки желаещ може да се присъедини като последва линка: \nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \nTopic: Онлайн семинар на секция “Алгебра и логика”\nTime: Nov 25\, 2022 01:00 PM Sofia\nMeeting ID: 851 3737 5021\nPasscode: 035647 \n\n\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%b0-91/
LOCATION:Zoom
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:20221028T130000
DTEND;TZID=Europe/Sofia:20221028T143000
DTSTAMP:20260405T143520
CREATED:20221025T141256Z
LAST-MODIFIED:20221025T141256Z
UID:13021-1666962000-1666967400@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 28 октомври 2022 г. (петък) от 13:00 ч. ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nGabbay Separation for the Duration Calculus\nще изнесе Димитър Гелев (ИМИ – БАН). \n\nАбстракт. Gabbay’s separation theorem about linear temporal logic (LTL) with past has proved to be one of the most useful theoretical results in temporal logic. Is expressive power ultimately affected\, if past constructs are not allowed in the scope of future ones\, or vice versa? Separation implies that it does not\, and also provides a technically convenient normal form for temporal conditions. \nInterval Temporal Logic (ITL) and the Duration Calculus (DC) are interval-based logics. Unlike LTL\, they are based on modalities which allow reference to subintervals of the reference intervals only. Adding the neighbourhood modalities\, which are written <A> and <A-1> in the notation stemming from Allen’s system of interval relations\, enables reference outside the reference interval and this way makes temporal separation relevant. In this talk I propose a DC analogue of a separation theorem for discrete time ITL which I established in a joint work with Ben Moszkowski. \nBoth theorems are analogous to Gabbay’s pioneering result and can be spelled out in similar terms\, but the technical differences are significant. I take the opportunity to not repeat my previous talk on separation for ITL and instead discuss some aspects of the proofs for both the ITL and the DC theorems. Interestingly\, these theorems admit proofs that are based on syntactical transformations of the formulas in the respective logics\, and are therefore compositional and very intuitive. I will focus on the common and the distinct features of the proofs\, and on some side corollaries. \n  \n\n\nСеминарът ще се проведе посредством платформата Zoom и всеки желаещ може да се присъедини като последва линка: \nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \nTopic: Онлайн семинар на секция “Алгебра и логика”\nTime: Oct 28\, 2022 01:00 PM Sofia\nMeeting ID: 851 3737 5021\nPasscode: 035647 \n\n\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%b0-90/
LOCATION:Zoom
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:20221021T130000
DTEND;TZID=Europe/Sofia:20221021T143000
DTSTAMP:20260405T143520
CREATED:20221018T214539Z
LAST-MODIFIED:20221018T214539Z
UID:12983-1666357200-1666362600@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 21 октомври 2022 г. (петък) от 13:00 ч. ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nRanks and Presentations for Order-Preserving Transformations with One Fixed Point\nще изнесе Jörg Koppitz (съвместна работа със S. Worawiset). \n\nАбстракт. We consider the semigroup (no monoid) of all order-preserving full transformations α on an n-element chain Xn = {1 < 2 …< n}\, where p is the only fixed point in α\, for some given p ∈Xn\, denoted by On\,p. This semigroup is nilpotent. In particular\, the semigroup On\,1 (i.e. p = 1) is already well studied\, since it is the maximal nilpotent subsemigroup of the Catalan monoid. But the semigroup On\,p is still not well studied for p > 1 except of p = n since On\,n is isomorphic to On\,1. We determine the rank of On\,p (it is Cp-1Cn-p – Cp-2Cn-p-1) and give a presentation of On\,p in (Cn-1 – Cn-2) generators and (1 + Cn-1 – Cn-2)(Cn-1 – Cn-2) relations. We illustrate the result for n = 4. \n  \n\n\nСеминарът ще се проведе посредством платформата Zoom и всеки желаещ може да се присъедини като последва линка: \nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \nTopic: Онлайн семинар на секция “Алгебра и логика”\nTime: Oct 21\, 2022 01:00 PM Sofia\nMeeting ID: 851 3737 5021\nPasscode: 035647 \n\n\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%b0-89/
LOCATION:Zoom
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:20221014T130000
DTEND;TZID=Europe/Sofia:20221014T143000
DTSTAMP:20260405T143520
CREATED:20221010T092028Z
LAST-MODIFIED:20221010T092028Z
UID:12923-1665752400-1665757800@math.bas.bg
SUMMARY:Семинар "Алгебра и логика"
DESCRIPTION:На 14 октомври 2022 г. (петък) от 13:00 ч. в зала 578 ще се проведе хибридно заседание на семинара по „Алгебра и логика”. \nДоклад на тема: \nСемейства от трилистни накрития на алгебрически криви\nще изнесе Христо Илиев (АУБ и ИМИ – БАН). \n\nАбстракт. Докладът е продължение на предишния ми доклад “Примери на нередуцирани компоненти на Хилбертовата схема от гладки проективни криви с използването на линейчати повърхнини”\, който беше представен на 19-ти август\, 2022г. В сегашния доклад разглеждамe трилистни накрития на гладки алгебрически криви от род γ ≥ 0. В резултат получаваме семейства от криви върху гладки повърхнинни скролове\, които при определени числени ограничения дават компоненти на Хилбертовата схема от криви. \n  \n\n\nСеминарът ще бъде излъчен и онлайн посредством платформата Zoom. Линк към Zoom-стаята на семинара: \nhttps://us02web.zoom.us/j/85137375021?pwd=RE5QczdFTE1xL1R6MnI2b1lkcGczQT09 \nTopic: Онлайн семинар на секция “Алгебра и логика”\nTime: Oct 14\, 2022 01:00 PM Sofia\nMeeting ID: 851 3737 5021\nPasscode: 035647 \n\n\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%b0-88/
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
END:VCALENDAR