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X-WR-CALNAME:Institute of Mathematics and Informatics
X-ORIGINAL-URL:https://math.bas.bg
X-WR-CALDESC:Събития за Institute of Mathematics and Informatics
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TZID:Europe/Sofia
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TZOFFSETFROM:+0200
TZOFFSETTO:+0300
TZNAME:EEST
DTSTART:20230326T010000
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BEGIN:STANDARD
TZOFFSETFROM:+0300
TZOFFSETTO:+0200
TZNAME:EET
DTSTART:20231029T010000
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BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20230926T140000
DTEND;TZID=Europe/Sofia:20230926T153000
DTSTAMP:20260407T052603
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:20230929T130000
DTEND;TZID=Europe/Sofia:20230929T143000
DTSTAMP:20260407T052603
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:20231009T143000
DTEND;TZID=Europe/Sofia:20231009T160000
DTSTAMP:20260407T052603
CREATED:20231009T104331Z
LAST-MODIFIED:20231010T073211Z
UID:15099-1696861800-1696867200@math.bas.bg
SUMMARY:Семинар "Дидактическо моделиране"
DESCRIPTION:Поредната сбирка на семинара \nДидактическо моделиране\nще се проведе на 09.10.2023 г. от 14:30 ч. в зала 278 на ИМИ. \nДоклад на тема \nМоделиране в задачи от две възстановени състезания\nще изнесат \nБоянка Савова и доц. Ивайло Кортезов.
URL:https://math.bas.bg/event/%d1%81%d0%b5%d0%bc%d0%b8%d0%bd%d0%b0%d1%80-%d0%b4%d0%b8%d0%b4%d0%b0%d0%ba%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%b5-32/
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:20231010T140000
DTEND;TZID=Europe/Sofia:20231010T153000
DTSTAMP:20260407T052603
CREATED:20231010T072649Z
LAST-MODIFIED:20231010T073059Z
UID:15105-1696946400-1696951800@math.bas.bg
SUMMARY:Семинар на МЦМН
DESCRIPTION:На 10.10.2023 г. (вторник) от 14:00 часа в зала 403 на ИМИ\nще се състои първата сбирка на семинара на МЦМН за 2023/2024 г. \nДоклад на тема: \nAbout a generalisation of Sylvester’s law of inertia\nще изнесе Stéphanie Cupit-Foutou (Ruhr Universitat\, Bohum). \nhttps://icms.bg/about-a-generalisation-of-sylvesters-law-of-inertia-talk-by-stephanie-cupit-foutou/ \nРезюме. 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
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-3/
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:20231013T130000
DTEND;TZID=Europe/Sofia:20231013T143000
DTSTAMP:20260407T052603
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:20231017T140000
DTEND;TZID=Europe/Sofia:20231017T153000
DTSTAMP:20260407T052603
CREATED:20231010T074351Z
LAST-MODIFIED:20231010T074351Z
UID:15108-1697551200-1697556600@math.bas.bg
SUMMARY:Семинар на МЦМН
DESCRIPTION:Дата: 17.10.2023 г.\, 14:00 ч. \nМясто: Зала 403\, ИМИ – БАН \nДокладчик: Михаил Школников\, ИМИ – БАН \nДоклад: Tropical structures in sandpile model \nРезюме: 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 often presented as a combinatorial version of algebraic geometry. I will tell how tropical curves arise in the scaling limit of the sandpile model in the vicinity of the maximal stable state and explain two major consequences inspired by this fact. The first one is that there is a continuous model for self-organized criticality\, the only known model of a kind\, defined in the realm of tropical geometry. The second is that the totality of recurrent states in the original sandpile model\, the sandpile group\, approximates a continuous group\, a tropical Abelian variety\, which is functorial with respect to inclusions of domains\, allowing to compute its scaling limit as a space of circle-valued harmonic functions on the whole lattice. \n\nTropical structures in sandpile model\, talk by Mikhail Shkolnikov\, IMI-BAS \n\n 
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-4/
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:20231017T140000
DTEND;TZID=Europe/Sofia:20231017T153000
DTSTAMP:20260407T052603
CREATED:20231010T182843Z
LAST-MODIFIED:20231010T182843Z
UID:15166-1697551200-1697556600@math.bas.bg
SUMMARY:Семинар на секция "Изследване на операциите\, вероятности и статистика"
DESCRIPTION:На 17 октомври 2023 (вторник) от 14:00 в зала 503 на ИМИ ще се проведе поредното заседание на семинара на секция „Изследване на операциите\, вероятности и статистика”. \nДоклад на тема: \nOn an Infinite-Time Horizon Linear-Quadratic Game with Constrained Control\nще изнесе Боян Стефанов.\n \nАбстракт. 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 original problem is reduced to a suitable finite-time horizon game. The main result is a sufficient condition for the existence of saddle point equilibrium. As an illustration\, the approach is applied to a basic monetary policy model. The discrete case is also briefly discussed.
URL:https://math.bas.bg/event/%d1%81%d0%b5%d0%bc%d0%b8%d0%bd%d0%b0%d1%80-%d0%bd%d0%b0-%d1%81%d0%b5%d0%ba%d1%86%d0%b8%d1%8f-%d0%b8%d0%b7%d1%81%d0%bb%d0%b5%d0%b4%d0%b2%d0%b0%d0%bd%d0%b5-%d0%bd%d0%b0-%d0%be%d0%bf%d0%b5%d1%80%d0%b0-5/
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%98%D0%B7%D1%81%D0%BB%D0%B5%D0%B4%D0%B2%D0%B0%D0%BD%D0%B5%20%D0%BD%D0%B0%20%D0%BE%D0%BF%D0%B5%D1%80%D0%B0%D1%86%D0%B8%D0%B8%D1%82%D0%B5%2C%20%D0%B2%D0%B5%D1%80%D0%BE%D1%8F%D1%82%D0%BD%D0%BE%D1%81%D1%82%D0%B8%20%D0%B8%20%D1%81%D1%82%D0%B0%D1%82%D0%B8%D1%81%D1%82%D0%B8%D0%BA%D0%B0":MAILTO:jeni@math.bas.bg;
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20231020T130000
DTEND;TZID=Europe/Sofia:20231020T143000
DTSTAMP:20260407T052603
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:20231023T143000
DTEND;TZID=Europe/Sofia:20231023T160000
DTSTAMP:20260407T052603
CREATED:20231019T090921Z
LAST-MODIFIED:20231019T090921Z
UID:15265-1698071400-1698076800@math.bas.bg
SUMMARY:Семинар "Дидактическо моделиране"
DESCRIPTION:Поредната сбирка на семинара \nДидактическо моделиране\nще се проведе на 23.10.2023 г. от 14:30 ч. в зала 278 на ИМИ. \nДоклад на тема \nВърху модели от математически лагери и програми за ученици с изследователска цел в Европа\nще изнесe \nМирослав Маринов.
URL:https://math.bas.bg/event/%d1%81%d0%b5%d0%bc%d0%b8%d0%bd%d0%b0%d1%80-%d0%b4%d0%b8%d0%b4%d0%b0%d0%ba%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%b5-33/
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:20231025T150000
DTEND;TZID=Europe/Sofia:20231025T163000
DTSTAMP:20260407T052603
CREATED:20231010T182251Z
LAST-MODIFIED:20231010T182251Z
UID:15162-1698246000-1698251400@math.bas.bg
SUMMARY:Семинар по Приложна математика
DESCRIPTION:Крайни автомати и невронни мрежи за езиково моделиране\nДокладчик: проф. Стоян Михов\nДата: 25.10.2023 г.\nЧас: 15:00 ч.\nМясто: Зала 503 на ИМИ-БАН \nРезюме: Езиковите модели са основен инструмент за решаването на редица сложни задачи като извличане на информация\, генерация на естествен език\, машинен превод\, речева комуникация и много други. Традиционно езиковите модели се представят с крайни преобразуватели. През последните години обаче езиковите модели\, базирани на невронни мрежи\, извършиха значителен скок в качеството на езиковото моделиране\, с което се постигнаха близки до човешки способности в много задачи за разбиране на естествен език. \nВ предстоящата лекция ще направим първо кратък преглед на традиционните представяния на езикови модели\, базирани на крайни преобразуватели. След това ще покажем често използвани архитектури на невронни мрежи за езиково моделиране и ще обсъдим техните предимства спрямо моделите\, базирани на крайни преобразуватели.\nВ третата част на лекцията ще представим нашия подход за конструиране на ансамбли от крайни автомати\, използвайки методите на дълбокото машинно обучение. По този начин ще комбинираме високото качество на невронните езикови модели с изчислителната ефективност на крайните автомати. Ще покажем\, че клас от архитектури на невронни мрежи е изчислително изоморфен на клас от ансамбли от крайни автомати.\nВ заключение\, ще представим емпирични резултати\, показващи\, че с помощта на нашия подход достигаме до перплексия (качество) на езиковите модели\, реализирани с ансамбли от крайни автомати\, конкурентна с перплексията на невронните езикови модели. \nФейсбук страница на семинара: Семинар по Приложна математика
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%bf%d1%80%d0%b8%d0%bb%d0%be%d0%b6%d0%bd%d0%b0-%d0%bc%d0%b0%d1%82%d0%b5%d0%bc%d0%b0%d1%82%d0%b8%d0%ba%d0%b0-6/
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
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20231030T140000
DTEND;TZID=Europe/Sofia:20231030T153000
DTSTAMP:20260407T052603
CREATED:20231010T080439Z
LAST-MODIFIED:20231010T080439Z
UID:15119-1698674400-1698679800@math.bas.bg
SUMMARY:Семинар на МЦМН
DESCRIPTION:Дата: 30.10.2023 г.\, 14:00 ч. \nМясто: Зала 403\, ИМИ – БАН \nДокладчик: Петър Далаков\, ИМИ – БАН \nКурс: Introduction to Projective Structures and Opers \nРезюме: 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. \n\nIntroduction to Projective Structures and Opers\, course by Peter Dalakov \n\n  \n 
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-6/
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:20231031T140000
DTEND;TZID=Europe/Sofia:20231031T153000
DTSTAMP:20260407T052603
CREATED:20231010T080721Z
LAST-MODIFIED:20231010T080721Z
UID:15124-1698760800-1698766200@math.bas.bg
SUMMARY:Семинар на МЦМН
DESCRIPTION:Дата: 31.10.2023 г.\, 14:00 ч. \nМясто: Зала 403\, ИМИ – БАН \nДокладчик: Петър Далаков\, ИМИ – БАН \nКурс: Introduction to Projective Structures and Opers \nРезюме: 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. \n\nIntroduction to Projective Structures and Opers\, course by Peter Dalakov \n\n  \n 
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-7/
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:20231031T160000
DTEND;TZID=Europe/Sofia:20231031T173000
DTSTAMP:20260407T052603
CREATED:20231026T165751Z
LAST-MODIFIED:20231026T165751Z
UID:15291-1698768000-1698773400@math.bas.bg
SUMMARY:Семинар на секция "Математически основи на информатиката"
DESCRIPTION:На 31 октомври 2023 г. (вторник) от 16:00 часа в зала 578 на ИМИ-БАН\nще се проведе заседание на семинара на секция\n„Математически основи на информатиката”. \nДоклад ще изнесе д-р Константин Воробьов (ИМИ – БАН). \nАбстракт. 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 different weight.\nWe also find exact values \(A_2(n\, {4\, 6})\) and \(A_2(n\, {6\, 8})\) starting from some \(n\). \nThis is a joint work with Ivan Landjev. \n 
URL:https://math.bas.bg/event/%d1%81%d0%b5%d0%bc%d0%b8%d0%bd%d0%b0%d1%80-%d0%bd%d0%b0-%d1%81%d0%b5%d0%ba%d1%86%d0%b8%d1%8f-%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%b8-%d0%be%d1%81%d0%bd%d0%be-19/
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:20231102T140000
DTEND;TZID=Europe/Sofia:20231102T153000
DTSTAMP:20260407T052603
CREATED:20231010T081045Z
LAST-MODIFIED:20231010T081045Z
UID:15128-1698933600-1698939000@math.bas.bg
SUMMARY:Семинар на МЦМН
DESCRIPTION:Дата: 02.11.2023 г.\, 14:00 ч. \nМясто: Зала 403\, ИМИ – БАН \nДокладчик: Петър Далаков\, ИМИ – БАН \nКурс: Introduction to Projective Structures and Opers \nРезюме: 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. \n\nIntroduction to Projective Structures and Opers\, course by Peter Dalakov \n\n  \n 
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-8/
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:20231103T130000
DTEND;TZID=Europe/Sofia:20231103T143000
DTSTAMP:20260407T052603
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:20231106T140000
DTEND;TZID=Europe/Sofia:20231106T153000
DTSTAMP:20260407T052603
CREATED:20231010T081237Z
LAST-MODIFIED:20231010T081237Z
UID:15132-1699279200-1699284600@math.bas.bg
SUMMARY:Семинар на МЦМН
DESCRIPTION:Дата: 06.11.2023 г.\, 14:00 ч. \nМясто: Зала 403\, ИМИ – БАН \nДокладчик: Петър Далаков\, ИМИ – БАН \nКурс: Introduction to Projective Structures and Opers \nРезюме: 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. \n\nIntroduction to Projective Structures and Opers\, course by Peter Dalakov \n\n  \n 
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-9/
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:20231107T140000
DTEND;TZID=Europe/Sofia:20231107T153000
DTSTAMP:20260407T052603
CREATED:20231103T065824Z
LAST-MODIFIED:20231103T065824Z
UID:15327-1699365600-1699371000@math.bas.bg
SUMMARY:Общ семинар на секция "Анализ\, геометрия и топология"
DESCRIPTION:Поредното заседание на Общия семинар на секция “Анализ\, геометрия и топология” ще се проведе\nна 7 ноември 2023 г. от 14:00 часа в зала 478 на ИМИ – БАН.\nДоклад на тема: \nNew and little known properties of the Fox and Fox-Wright functions\nще изнесе Dmitrii Karp\, Holon Institute of Technology\, Holon\, Israel. \nПоканват се всички интересуващи се. \nРезюме. 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 further present positivity conditions for the so-called delta-neutral case of Fox’s H function making it a probability distribution (widely used in statistics)\, which rely on complete monotonicity of certain product ratios of Gamma functions. Moreover\, I will exhibit a new integral equation for Fox’s H function and a conjecture regarding its zeros. Finally\, some open problems will be presented. \n\n 
URL:https://math.bas.bg/event/%d0%be%d0%b1%d1%89-%d1%81%d0%b5%d0%bc%d0%b8%d0%bd%d0%b0%d1%80-%d0%bd%d0%b0-%d1%81%d0%b5%d0%ba%d1%86%d0%b8%d1%8f-%d0%b0%d0%bd%d0%b0%d0%bb%d0%b8%d0%b7-%d0%b3%d0%b5%d0%be%d0%bc%d0%b5%d1%82%d1%80%d0%b8-21/
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%BD%D0%B0%D0%BB%D0%B8%D0%B7%2C%20%D0%B3%D0%B5%D0%BE%D0%BC%D0%B5%D1%82%D1%80%D0%B8%D1%8F%20%D0%B8%20%D1%82%D0%BE%D0%BF%D0%BE%D0%BB%D0%BE%D0%B3%D0%B8%D1%8F":MAILTO:vmil@math.bas.bg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20231108T140000
DTEND;TZID=Europe/Sofia:20231108T153000
DTSTAMP:20260407T052603
CREATED:20231106T100342Z
LAST-MODIFIED:20231106T100342Z
UID:15346-1699452000-1699457400@math.bas.bg
SUMMARY:Национален семинар по стохастика
DESCRIPTION:Поредната сбирка на \nНационалния семинар по стохастика\nще се проведе на 8 ноември 2023 г. (сряда) от 14:00 часа в зала 503 на ИМИ – БАН. \nДоклад на тема \nHamiltonicity of randomly perturbed graphs\nще изнесе \nAlberto Espuny Díaz (Postdoctoral researcher at Universität Heidelberg\, Germany). \nАбстракт: 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 problem. \nIn this talk I will survey some results in the area and focus particularly on the Hamiltonicity problem\, which has often been used as a test for many techniques in graph theory. I will present several variants of the problem\, as well as some results for each of these variants. The talk is based on joint works with Alexander Allin\, António Girão\, and Joseph Hyde. \n 
URL:https://math.bas.bg/event/%d0%bd%d0%b0%d1%86%d0%b8%d0%be%d0%bd%d0%b0%d0%bb%d0%b5%d0%bd-%d1%81%d0%b5%d0%bc%d0%b8%d0%bd%d0%b0%d1%80-%d0%bf%d0%be-%d1%81%d1%82%d0%be%d1%85%d0%b0%d1%81%d1%82%d0%b8%d0%ba%d0%b0-37/
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
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20231108T140000
DTEND;TZID=Europe/Sofia:20231108T153000
DTSTAMP:20260407T052603
CREATED:20231108T185838Z
LAST-MODIFIED:20231108T185838Z
UID:15391-1699452000-1699457400@math.bas.bg
SUMMARY:Национален семинар по стохастика
DESCRIPTION:Поредната сбирка на \nНационалния семинар по стохастика\nще се проведе на 15 ноември 2023 г. (сряда) от 14:00 часа в зала 503 на ИМИ – БАН. \nДоклад на тема \nAnti-concentration of Rademacher sums and Tomaszewski’s counterpart problem\nще изнесе \nJulien Portier\, University of Cambridge. \nАбстракт \n 
URL:https://math.bas.bg/event/%d0%bd%d0%b0%d1%86%d0%b8%d0%be%d0%bd%d0%b0%d0%bb%d0%b5%d0%bd-%d1%81%d0%b5%d0%bc%d0%b8%d0%bd%d0%b0%d1%80-%d0%bf%d0%be-%d1%81%d1%82%d0%be%d1%85%d0%b0%d1%81%d1%82%d0%b8%d0%ba%d0%b0-38/
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
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20231108T160000
DTEND;TZID=Europe/Sofia:20231108T173000
DTSTAMP:20260407T052603
CREATED:20231106T052112Z
LAST-MODIFIED:20231106T052112Z
UID:15342-1699459200-1699464600@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващото заседание на семинара по геометрия на МЦМН ще се проведе на\n8 ноември 2023 г.\, сряда\, от 16:00 ч. в зала 403 и онлайн. Доклад на тема \nTropicalizations II\nще изнесе Михаил Школников\, ИМИ – БАН. \nАбстракт: 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 their tropicalizations\, exemplified by the phase tropical limit having the same topology as corresponding complex hypersurfaces provided that the usual tropicalization is smooth. \n\nTropicalizations II\, a talk by M. Shkolnikov \n\nZoom link:\n https://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09
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/
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:20231110T130000
DTEND;TZID=Europe/Sofia:20231110T143000
DTSTAMP:20260407T052603
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:20231110T140000
DTEND;TZID=Europe/Sofia:20231110T153000
DTSTAMP:20260407T052603
CREATED:20231106T143730Z
LAST-MODIFIED:20231106T144427Z
UID:15357-1699624800-1699630200@math.bas.bg
SUMMARY:Семинар на секция "Математически основи на информатиката"
DESCRIPTION:На 10 ноември 2023 г. (вторник) от 14:00 часа в зала 478 на ИМИ-БАН\nще се проведе заседание на семинара на секция\n„Математически основи на информатиката”. \nДоклад на тема \nOn induced \(C_4\)-free graphs with high average degree\nще изнесе Антонио Жирао. \nАбстракт.  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 is \(C_4\)-free with average degree \(k\). \nWe will talk about a recent result which strengthens this result of Kühn and Osthus in two ways. First\, we prove an analogous induced version and secondly we give much better bounds for the function f allowing us obtain few non-trivial results as simple corollaries. Finally\, we use these methods to confirm a conjecture Bonamy et al.\nАнтонио Жирао e пост-докторант в Оксфордския Университет под ръководството на проф. Алекс Скот. Преди да заеме тази позиция\, Антонио работи като пост-докторант в Хайделбергския Университет под ръководството на проф. Феликс Йоос и в Университета в Бирмингам под ръководството на проф. Даниела Кюн и проф. Дерек Остюс. Защитава докторантурата в Университета в Кеймбридж под ръководството на проф. Бела Болобаш през 2018 г.
URL:https://math.bas.bg/event/%d1%81%d0%b5%d0%bc%d0%b8%d0%bd%d0%b0%d1%80-%d0%bd%d0%b0-%d1%81%d0%b5%d0%ba%d1%86%d0%b8%d1%8f-%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%b8-%d0%be%d1%81%d0%bd%d0%be-20/
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:20231114T140000
DTEND;TZID=Europe/Sofia:20231114T153000
DTSTAMP:20260407T052603
CREATED:20231010T083449Z
LAST-MODIFIED:20231010T090357Z
UID:15136-1699970400-1699975800@math.bas.bg
SUMMARY:Семинар на МЦМН
DESCRIPTION:Дата: 14.11.2023 г.\, 14:00 ч. \nМясто: Зала 403\, ИМИ – БАН \nДокладчик: Валдемар Цанов\, ИМИ – БАН \nКурс: Invariant theory\, homogeneous projective varieties\, and momentum maps \nРезюме: 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. \n\nThe ring of -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.\nThe \(K\)-equivariant momentum map \(\mu:\mathbb P(V)\to \mathfrak k^*\) associated to the Fubini-Study form encodes in its image properties of the invariant ring \(\mathbb C[V]^K\) and the \(K\)-module structure of the entire polynomial ring \(\mathbb C[V]\)\, due to theorems of Mumford and Brion. While many general properties of momentum images have been established\, explicit descriptions remain unknown in many cases south for in physics and quantum information theory.\nProjective geometry of complex \(K\)-orbits in \(\mathbb P(V)\); their fundamental forms\, osculating varieties and secant varieties.\n\nGeneral relations between the first two topics are well established\, even in a more general context. There are also well known relations between invariant theory and projective geometry\, but secant varieties have only recently been brought to the discussion and are subject of current interest. \nAfter introducing the basic notions\, I will derive some properties of momentum images related to fundamental forms and osculating varieties\, as well as a lower bound on the minimal positive degree of a homogeneous invariant\, derived using secant varieties. At the end I will present a class of homogeneous projective varieties\, characterized by a special property of their secant varieties\, where the relations between the above three concepts take a particularly pristine form. \n\nInvariant theory\, homogeneous projective varieties\, and momentum maps\, course by Valdemar Tsanov \n\n 
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-10/
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:20231114T140000
DTEND;TZID=Europe/Sofia:20231114T153000
DTSTAMP:20260407T052603
CREATED:20231110T170235Z
LAST-MODIFIED:20231110T170235Z
UID:15406-1699970400-1699975800@math.bas.bg
SUMMARY:Семинар по Приложна математика
DESCRIPTION:How log-concavity fought lottery frauds in Florida and what it did after winning\nДокладчик: Дмитри Карп\nДата: 14.11.2023 г.\nЧас: 14:00 ч.\nМясто: Зала 503 на ИМИ-БАН \nРезюме: 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. \nФейсбук страница на семинара: Семинар по Приложна математика
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%bf%d1%80%d0%b8%d0%bb%d0%be%d0%b6%d0%bd%d0%b0-%d0%bc%d0%b0%d1%82%d0%b5%d0%bc%d0%b0%d1%82%d0%b8%d0%ba%d0%b0-7/
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
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20231114T161500
DTEND;TZID=Europe/Sofia:20231114T173000
DTSTAMP:20260407T052603
CREATED:20231110T160109Z
LAST-MODIFIED:20231110T160109Z
UID:15397-1699978500-1699983000@math.bas.bg
SUMMARY:Национален колоквиум по математика
DESCRIPTION:СЪЮЗ НА МАТЕМАТИЦИТЕ В БЪЛГАРИЯ\n\nИНСТИТУТ ПО МАТЕМАТИКА И ИНФОРМАТИКА – БАН \n\n\n\nНАЦИОНАЛЕН КОЛОКВИУМ ПО МАТЕМАТИКА\n\n​Поредната сбирка на Колоквиума ще се състои на 14 ноември 2023 г. (вторник)  от 16:15 часа в Заседателната зала на ИМИ – БАН. Доклад на тема:\n\nArcs of High Divisibility and Their Applications to Coding Theory\nще изнесе проф. дмн Иван Ланджев\,\nИнститут по матем​атика и информатика\, Българска академия на науките. \n\n\n​Резюме
URL:https://math.bas.bg/event/%d0%bd%d0%b0%d1%86%d0%b8%d0%be%d0%bd%d0%b0%d0%bb%d0%b5%d0%bd-%d0%ba%d0%be%d0%bb%d0%be%d0%ba%d0%b2%d0%b8%d1%83%d0%bc-%d0%bf%d0%be-%d0%bc%d0%b0%d1%82%d0%b5%d0%bc%d0%b0%d1%82%d0%b8%d0%ba%d0%b0-26/
LOCATION:Институт по математика и информатика – БАН\, Block 8\, 1113 БАН IV км.\, София\, Bulgaria
CATEGORIES:Редовен семинар
ORGANIZER;CN="%D0%A1%D1%8A%D1%8E%D0%B7%20%D0%BD%D0%B0%20%D0%BC%D0%B0%D1%82%D0%B5%D0%BC%D0%B0%D1%82%D0%B8%D1%86%D0%B8%D1%82%D0%B5%20%D0%B2%20%D0%91%D1%8A%D0%BB%D0%B3%D0%B0%D1%80%D0%B8%D1%8F":MAILTO:smb.sofia@gmail.com
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20231115T160000
DTEND;TZID=Europe/Sofia:20231115T173000
DTSTAMP:20260407T052603
CREATED:20231110T165607Z
LAST-MODIFIED:20231110T165607Z
UID:15402-1700064000-1700069400@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 15 ноември 2023 г. от 16:00 ч. в зала 403 и онлайн в Zoom:\n\nTopics in non-archimedean analytic geometry (I)\, \nby Jiachang Xu – International Center for Mathematical Sciences (ICMS – Sofia)\n\nZoom link:\n\nhttps://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09
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-2/
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
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20231116T140000
DTEND;TZID=Europe/Sofia:20231116T153000
DTSTAMP:20260407T052603
CREATED:20231010T091536Z
LAST-MODIFIED:20231010T091536Z
UID:15145-1700143200-1700148600@math.bas.bg
SUMMARY:Семинар на МЦМН
DESCRIPTION:Дата: 16.11.2023 г.\, 14:00 ч. \nМясто: Зала 403\, ИМИ – БАН \nДокладчик: Валдемар Цанов\, ИМИ – БАН \nКурс: Invariant theory\, homogeneous projective varieties\, and momentum maps \nРезюме: 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. \n\nThe ring of -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.\nThe \(K\)-equivariant momentum map \(\mu:\mathbb P(V)\to \mathfrak k^*\) associated to the Fubini-Study form encodes in its image properties of the invariant ring \(\mathbb C[V]^K\) and the \(K\)-module structure of the entire polynomial ring \(\mathbb C[V]\)\, due to theorems of Mumford and Brion. While many general properties of momentum images have been established\, explicit descriptions remain unknown in many cases south for in physics and quantum information theory.\nProjective geometry of complex \(K\)-orbits in \(\mathbb P(V)\); their fundamental forms\, osculating varieties and secant varieties.\n\nGeneral relations between the first two topics are well established\, even in a more general context. There are also well known relations between invariant theory and projective geometry\, but secant varieties have only recently been brought to the discussion and are subject of current interest. \nAfter introducing the basic notions\, I will derive some properties of momentum images related to fundamental forms and osculating varieties\, as well as a lower bound on the minimal positive degree of a homogeneous invariant\, derived using secant varieties. At the end I will present a class of homogeneous projective varieties\, characterized by a special property of their secant varieties\, where the relations between the above three concepts take a particularly pristine form. \n\nInvariant theory\, homogeneous projective varieties\, and momentum maps\, course by Valdemar Tsanov \n\n 
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-11/
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:20231117T130000
DTEND;TZID=Europe/Sofia:20231117T143000
DTSTAMP:20260407T052603
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:20231120T143000
DTEND;TZID=Europe/Sofia:20231120T160000
DTSTAMP:20260407T052603
CREATED:20231116T054743Z
LAST-MODIFIED:20231116T054743Z
UID:15415-1700490600-1700496000@math.bas.bg
SUMMARY:Семинар "Дидактическо моделиране"
DESCRIPTION:Поредната сбирка на семинара \nДидактическо моделиране\nще се проведе на 20.11.2023 г. от 14:30 ч. в зала 278 на ИМИ. \nДоклад на тема \nТочкуване на задачи и използване на скàли при стандартизирани оценявания\nще изнесe \nпроф. Кирил Банков.
URL:https://math.bas.bg/event/%d1%81%d0%b5%d0%bc%d0%b8%d0%bd%d0%b0%d1%80-%d0%b4%d0%b8%d0%b4%d0%b0%d0%ba%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%b5-34/
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:20231121T140000
DTEND;TZID=Europe/Sofia:20231121T153000
DTSTAMP:20260407T052603
CREATED:20231010T091730Z
LAST-MODIFIED:20231010T091730Z
UID:15149-1700575200-1700580600@math.bas.bg
SUMMARY:Семинар на МЦМН
DESCRIPTION:Дата: 21.11.2023 г.\, 14:00 ч. \nМясто: Зала 403\, ИМИ – БАН \nДокладчик: Валдемар Цанов\, ИМИ – БАН \nКурс: Invariant theory\, homogeneous projective varieties\, and momentum maps \nРезюме: 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. \n\nThe ring of -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.\nThe \(K\)-equivariant momentum map \(\mu:\mathbb P(V)\to \mathfrak k^*\) associated to the Fubini-Study form encodes in its image properties of the invariant ring \(\mathbb C[V]^K\) and the \(K\)-module structure of the entire polynomial ring \(\mathbb C[V]\)\, due to theorems of Mumford and Brion. While many general properties of momentum images have been established\, explicit descriptions remain unknown in many cases south for in physics and quantum information theory.\nProjective geometry of complex \(K\)-orbits in \(\mathbb P(V)\); their fundamental forms\, osculating varieties and secant varieties.\n\nGeneral relations between the first two topics are well established\, even in a more general context. There are also well known relations between invariant theory and projective geometry\, but secant varieties have only recently been brought to the discussion and are subject of current interest. \nAfter introducing the basic notions\, I will derive some properties of momentum images related to fundamental forms and osculating varieties\, as well as a lower bound on the minimal positive degree of a homogeneous invariant\, derived using secant varieties. At the end I will present a class of homogeneous projective varieties\, characterized by a special property of their secant varieties\, where the relations between the above three concepts take a particularly pristine form. \n\nInvariant theory\, homogeneous projective varieties\, and momentum maps\, course by Valdemar Tsanov \n\n 
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-12/
LOCATION:Институт по математика и информатика – БАН\, Block 8\, 1113 БАН IV км.\, София\, Bulgaria
CATEGORIES:Редовен семинар
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