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BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20250507T160000
DTEND;TZID=Europe/Sofia:20250507T173000
DTSTAMP:20260419T235556
CREATED:20250505T165639Z
LAST-MODIFIED:20250505T170018Z
UID:17708-1746633600-1746639000@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 7 май 2025 г. от 16:00 ч. в зала 403 и онлайн в Zoom: \nДоклад на тема \nBinary Quadratic Forms and Conway’s Topographs (Lecture 2 of 3)\n\nще изнесе Nikita Kalinin\, Guangdong Technion Israel Institute of Technology. \n\nСледващата лекция ще бъде на 14.05.2025 от 16:00 ч.\n\nAbstract: Binary quadratic forms are as elementary as they are mysterious—much like prime numbers. In 1997\, John Conway introduced topographs\, a powerful geometric tool that provides a geometric visualization of binary quadratic forms and their values. These lectures will explore how topographs\, combined with telescoping summation techniques\, yield elegant formulas — some with intuitive geometric interpretations. For instance\, consider the following result: \nLet \n\(A = \big\{ (x\, y) \mid  x\,y\in \mathbb{Z}_{\geq 0}^2\, \det(x \ \ y) = 1 \big\}\,\) \nthe set of pairs of lattice vectors in the first quadrant spanning a parallelogram of oriented area 1. Then\, \n\(4 \displaystyle\sum_{(x\,y) \in A} \frac{1}{|x|^2 \cdot |y|^2 \cdot |x+y|^2} = \pi.\) \nLecture Outline \n1. Introduction to Binary Quadratic Forms and Conway’s Topographs\nWe will begin with the basics of binary quadratic forms and their classification\, followed by an introduction to Conway’s topographs—a visual and geometric framework for understanding them. \n2. Class Number Formula and Summation over Topographs\nBuilding on the first lecture\, we will explore the class number formula and how summation identities arise naturally from the structure of topographs. \n3. Evaluation of Lattice Sums via Telescoping over Topographs\nThe final lecture will focus on telescoping techniques\, demonstrating how they can be used to evaluate intricate lattice sums—such as the one above—with geometric meaning. \n\n\nZoom link:\nhttps://us02web.zoom.us/j/86186281353?pwd=6CARUygJaA3HiTNAt3norZQRFt8fIL.1\n\nВидеозапис и презентация на първата лекция:\n\nhttps://youtu.be/z7Pz33JyCuA?si=rQ2L4yXJHMdiDkpe\nhttps://kilin-math.github.io/assets/numbers/telescopic_presentation1.pdf
URL:https://math.bas.bg/event/copy-%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-3/
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:20250430T160000
DTEND;TZID=Europe/Sofia:20250430T173000
DTSTAMP:20260419T235556
CREATED:20250424T092412Z
LAST-MODIFIED:20250424T093036Z
UID:17661-1746028800-1746034200@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 30 април 2025 г. от 16:00 ч. в зала 403 и онлайн в Zoom: \nДоклад на тема \nBinary Quadratic Forms and Conway’s Topographs (Lecture 1 of 3)\n\nще изнесе Nikita Kalinin\, Guangdong Technion Israel Institute of Technology. \n\nСледващите две лекции ще бъдат на 07.05.2025 и 14.05.2025 от 16:00 ч.\n\nAbstract: Binary quadratic forms are as elementary as they are mysterious—much like prime numbers. In 1997\, John Conway introduced topographs\, a powerful geometric tool that provides a geometric visualization of binary quadratic forms and their values. These lectures will explore how topographs\, combined with telescoping summation techniques\, yield elegant formulas — some with intuitive geometric interpretations. For instance\, consider the following result: \nLet \n\(A = \big\{ (x\, y) \mid  x\,y\in \mathbb{Z}_{\geq 0}^2\, \det(x \ \ y) = 1 \big\}\,\) \nthe set of pairs of lattice vectors in the first quadrant spanning a parallelogram of oriented area 1. Then\, \n\(4 \displaystyle\sum_{(x\,y) \in A} \frac{1}{|x|^2 \cdot |y|^2 \cdot |x+y|^2} = \pi.\) \nLecture Outline \n1. Introduction to Binary Quadratic Forms and Conway’s Topographs\nWe will begin with the basics of binary quadratic forms and their classification\, followed by an introduction to Conway’s topographs—a visual and geometric framework for understanding them. \n2. Class Number Formula and Summation over Topographs\nBuilding on the first lecture\, we will explore the class number formula and how summation identities arise naturally from the structure of topographs. \n3. Evaluation of Lattice Sums via Telescoping over Topographs\nThe final lecture will focus on telescoping techniques\, demonstrating how they can be used to evaluate intricate lattice sums—such as the one above—with geometric meaning. \n\n\nZoom link:\nhttps://us02web.zoom.us/j/86186281353?pwd=6CARUygJaA3HiTNAt3norZQRFt8fIL.1
URL:https://math.bas.bg/event/%d1%81%d0%b5%d0%bc%d0%b8%d0%bd%d0%b0%d1%80-%d0%bf%d0%be-%d0%b3%d0%b5%d0%be%d0%bc%d0%b5%d1%82%d1%80%d0%b8%d1%8f-%d0%bd%d0%b0-%d0%bc%d1%86%d0%bc%d0%bd-15/
LOCATION:Институт по математика и информатика – БАН\, Block 8\, 1113 БАН IV км.\, София\, Bulgaria
CATEGORIES:Редовен семинар
ORGANIZER;CN="%D0%98%D0%BD%D1%81%D1%82%D0%B8%D1%82%D1%83%D1%82%20%D0%BF%D0%BE%20%D0%BC%D0%B0%D1%82%D0%B5%D0%BC%D0%B0%D1%82%D0%B8%D0%BA%D0%B0%20%D0%B8%20%D0%B8%D0%BD%D1%84%D0%BE%D1%80%D0%BC%D0%B0%D1%82%D0%B8%D0%BA%D0%B0%20-%20%D0%91%D0%90%D0%9D":MAILTO:office@math.bas.bg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Sofia:20241204T160000
DTEND;TZID=Europe/Sofia:20241204T173000
DTSTAMP:20260419T235556
CREATED:20241204T154928Z
LAST-MODIFIED:20241204T155031Z
UID:17057-1733328000-1733333400@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 4 ДЕКЕМВРИ 2024 г. от 16:00 ч. в зала 403 и онлайн в Zoom: \nДоклад на тема \nTropical compactifications of moduli spaces – Part 2\n\nще изнесе Лайънъл Ланг\, Международен център по математически науки (МЦМН – София). \n\n\n\nAbstract: In this talk I will describe various tropical compactifications of the moduli spaces of curves. I will discuss some motivations and applications coming from tropical geometry (joint with M. Melo\, J. Rau and F. Viviani). \n\n\nZoom link:\nhttps://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09
URL:https://math.bas.bg/event/copy-%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:20241127T160000
DTEND;TZID=Europe/Sofia:20241127T173000
DTSTAMP:20260419T235556
CREATED:20241122T093719Z
LAST-MODIFIED:20241122T093719Z
UID:16962-1732723200-1732728600@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 27 ноември 2024 г. от 16:00 ч. в зала 403 и онлайн в Zoom: \nДоклад на тема \nTropical compactifications of moduli spaces\n\nще изнесе Лайънъл Ланг\, Международен център по математически науки (МЦМН – София). \n\n\n\nAbstract: In this talk I will describe various tropical compactifications of the moduli spaces of curves. I will discuss some motivations and applications coming from tropical geometry (joint with M. Melo\, J. Rau and F. Viviani). \n\n\nZoom link:\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-14/
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:20240515T160000
DTEND;TZID=Europe/Sofia:20240515T173000
DTSTAMP:20260419T235556
CREATED:20240513T072858Z
LAST-MODIFIED:20240513T072922Z
UID:16290-1715788800-1715794200@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 15 май 2024 г. от 16:00 ч. в зала 403 и онлайн в Zoom: \nДоклад на тема \nHyperbolic amoebas\n\nще изнесе Михаил Школников\, ИМИ – БАН. \n\n\n\nAbstract: Classical amoebas serve as a tool to study algebraic varieties and as one of the entry points to tropical geometry. The original definition involves a logarithmic projection of a subvariety of a complex algebraic torus\, which can be interpreted as forgetting the phase\, i.e. the arguments of complex numbers. In group-theoretic terms\, this projection map may be thought of as passing to the quotient by the maximal compact subgroup. Suppose one replaces the algebraic torus with a complex three-dimensional matrix group. In that case\, the analogous projection naturally has a three-dimensional hyperbolic space as its target\, and it still makes sense to consider images\, i.e. hyperbolic amoebas\, of complex algebraic varieties under this map. I will review some of the basic properties of hyperbolic amoebas\, extending a fascinating interplay between complex and hyperbolic geometries.Based on joint work with Grigory Mikhalkin. \n\n\nZoom link:\nhttps://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09
URL:https://math.bas.bg/event/copy-%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
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:20240424T160000
DTEND;TZID=Europe/Sofia:20240424T173000
DTSTAMP:20260419T235556
CREATED:20240422T220816Z
LAST-MODIFIED:20240422T220816Z
UID:16246-1713974400-1713979800@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 24 април 2024 г. от 16:00 ч. в зала 403: \nДоклад на тема \nGeneralised Plucker formula\n\nще изнесе Андрей Бенгуш-Ласние\, МЦМН. \n\n\nAbstract: In order to classify objects in singularity theory and algebraic geometry\, we define invariants associated to varieties or germs of singularities and hope to have enough tools to compute them easily. From classical projective duality\, for any variety \(X\)\, we can define a dual variety \(X∗\) and we call the class of \(X\) the degree of \(X∗\). Plücker’s formula allows one to compute this class for plane curves with a certain set of nodes\, cusps and tacnodes.\nWe will start our talk by recalling the general Bézout theorem and then present the Plücker-Teissier formula\, which generalises Plücker’s formula to hypersurfaces\, and we will sketch a method to generalise the approach to its proof to general complete intersections.\n\nZoom link:\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-13/
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:20240327T160000
DTEND;TZID=Europe/Sofia:20240327T173000
DTSTAMP:20260419T235556
CREATED:20240326T081032Z
LAST-MODIFIED:20240326T081032Z
UID:16111-1711555200-1711560600@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 27 март 2024 г. от 16:00 ч. в зала 403: \nДоклад на тема \nReading seminar of geometric Lubin-Tate theory\n\nще изнесе Jiachang Xu\, ИМИ – БАН. \n\n\nAbstract: This is reading seminar of geometry of Lubin-Tate theory\, our goal is to understand the papers “M. J. Hopkins and B. H. Gross\, Equivariant vector bundles on the Lubin-Tate moduli space” and “Ramero\, Lorenzo On a class of étale analytic sheaves”. The first seminar we plan to go over the basis of deformation theory\, formal group and necessary rigid geometry.\n\nZoom link:\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-12/
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:20240320T160000
DTEND;TZID=Europe/Sofia:20240320T173000
DTSTAMP:20260419T235556
CREATED:20240315T080032Z
LAST-MODIFIED:20240315T080032Z
UID:16056-1710950400-1710955800@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 20 март 2024 г. от 16:00 ч. в зала 403: \nДоклад на тема \nEllipsoid superpotentials: obstructing symplectic embeddings by singular algebraic curves\n\nще изнесе Григори Михалкин\, Женевски университет. \n\n\nAbstract: How singular can be a local branch of a plane algebraic curve of a given degree d? A remarkable series of real algebraic curves was constructed by Stepan Orevkov. It is based on even-indexed numbers in the Fibonacci series: a degree 5 curve with a 13/2 cusp\, a degree 13 curve with a 34/5-cusp\, and so on. We discuss this and other series of algebraic curves in the context of the problem of symplectic packing of an ellipsoid into a ball\, with the answer given by the spectacular Fibonacci staircase of McDuff and Schlenk. The aspect ratio a>1 of the ellipsoid can be viewed as a real parameter for a certain enumerative superpotential function\, which is mostly locally constant\, but jumps at certain specific rational values (responsible for the aspects of cusp singularities). Based on joint work with Kyler Siegel.\n\nТова заседание на семинара няма да се излъчва в Zoom.
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-11/
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:20240228T160000
DTEND;TZID=Europe/Sofia:20240228T173000
DTSTAMP:20260419T235556
CREATED:20240222T091637Z
LAST-MODIFIED:20240222T091637Z
UID:15979-1709136000-1709141400@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 28 февруари 2024 г. от 16:00 ч. в зала 403 и онлайн в Zoom: \nДоклад на тема \nLinear embeddings of complex Grassmannians\n\nще изнесе Иван Пенков\, Constructor University Bremen. \n\nZoom link:\n\nhttps://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09\n\nAbstract: A linear embedding of Grassmannians\, one of which could possibly be isotropic\, is an embedding which respects the generators of Picard groups. Several years ago A.S. Tikhomirov and I classified such embeddings when both Grassmannians are simultaneously usual Grassmannians or isotropic Grassmannians of the same type(orthogonal or symplectic). In this talk I will discuss also the mixed case. A classification as above has an application to the classification of infinite-dimensional linear ind-Grassmannians\, and I shall  briefly explain this at the end of the talk.
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-10/
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:20240214T160000
DTEND;TZID=Europe/Sofia:20240214T173000
DTSTAMP:20260419T235556
CREATED:20240212T133658Z
LAST-MODIFIED:20240212T133658Z
UID:15958-1707926400-1707931800@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 14 февруари 2024 г. от 16:00 ч. в зала 403 и онлайн в Zoom: \nДоклад на тема \nRefined curve counting\n\nще изнесе Михаил Школников\, ИМИ – БАН. \n\nZoom link:\n\nhttps://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09\n\nAbstract: Refining an enumerative problem upgrades the numerical solution to a polynomial so that its specialization gives the original number. A prototypical example of such refinement arises in the tropical curve counting from replacing Mikhalkin multiplicities\, corresponding to counting complex curves\, with Block-Goettsche multiplicities. I will speak about the invariance of this count and its various interpretations.
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-9/
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:20240207T160000
DTEND;TZID=Europe/Sofia:20240207T173000
DTSTAMP:20260419T235556
CREATED:20240205T211554Z
LAST-MODIFIED:20240205T211820Z
UID:15925-1707321600-1707327000@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 7 февруари 2024 г. от 16:00 ч. в зала 403 и онлайн в Zoom: \nДоклад на тема \nIntroduction to curve counting\n\nще изнесе Михаил Школников\, ИМИ – БАН. \n\nZoom link:\n\nhttps://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09\n\nAbstract: This talk is intended as a very gentle introduction to the classical subject of enumerative geometry concerned with problems of counting algebraic curves with prescribed properties. In the realm of classical planimetry\, we know that there exists a single circle passing through a collection of three points\, provided that these points are generic. Here “generic” simply means that the points are not collinear\, i.e. don’t belong to the same line but could refer to some other open condition in a different context; the number of points is just right for a problem to be well-stated — there are infinitely many circles passing through any two points and a collection of four points lying on a circle is special. A less trivial example\, which will be considered in detail\, is the question “How many rational cubic curves on the plane pass through a generic collection of eight points?”. “Rational” here means that a curve has a parametrization by rational functions\, and “cubic” refers to a curve defined as a zero locus of a degree three polynomial. The number of points is again chosen just right so that one may expect a non-trivial answer. In the case of real algebraic geometry\, the number of cubics may vary depending on the position of the eight generic points\, and a priori it is even not clear if such curves exist for all configurations. On the other hand\, if we state the same problem over complex numbers the answer becomes definite and independent of the position of the generic points. By an elegant\, yet quite elementary\, topological reasoning we will deduce that this answer is 12. Adapting the same argument in the real case\, we will see that real rational cubics should be counted with signs and the result of this new count becomes a definite -8\, proving in particular that for any generic configuration of eight points on the real plane\, there exist at least eight rational real cubics passing through them.
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-8/
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:20240131T160000
DTEND;TZID=Europe/Sofia:20240131T173000
DTSTAMP:20260419T235556
CREATED:20240130T125552Z
LAST-MODIFIED:20240130T125552Z
UID:15893-1706716800-1706722200@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 31 януари 2024 г. от 16:00 ч. в зала 403 и онлайн в Zoom: \nДоклад на тема \nDerived Deformation Theory and Formal Moduli Problem\n\nще изнесе Инди Чин\, МЦМН и ИМИ – БАН. \n\nZoom link:\n\nhttps://us02web.zoom.us/j/83740034721?pwd=VnBtcVpGUktscHQ4a09jZkNZTURyZz09\n\nAbstract: Derived deformation theory studies the formal neighborhoods of moduli spaces. The classical work of Kodaira-Spencer on deformation of complex manifolds tells that the dg Lie algebra A^(0\,*)(X\,TX) controls the deformations of the complex manifold. The example illustrates the following general principle: A dg Lie algebra gives rise to a deformation functor by considering the  Maurer-Cartan elements of the dg Lie algebra tensoring with the maximal ideal of an Artin local ring. This idea is explored by many people\, including  Quillen\, Deligne\, Drinfeld\,  Kapranov and Kontesevich. Later\, Lurie and Pridham independently proved that the category of dg Lie algebra is indeed equivalent to the category of Formal Moduli problem. I will state their results and explain the idea of the proof.
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-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:20240124T160000
DTEND;TZID=Europe/Sofia:20240124T173000
DTSTAMP:20260419T235556
CREATED:20240122T092832Z
LAST-MODIFIED:20240122T092833Z
UID:15875-1706112000-1706117400@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 24 януари 2024 г. от 16:00 ч. в зала 403 и онлайн в Zoom: \nДоклад на тема \nIntroduction to Derived Algebraic Geometry and deformation theory\n\nще изнесе Инди Чин\, ИМИ – БАН. \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-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:20231213T160000
DTEND;TZID=Europe/Sofia:20231213T173000
DTSTAMP:20260419T235556
CREATED:20231207T212005Z
LAST-MODIFIED:20231207T212005Z
UID:15684-1702483200-1702488600@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 13 декември 2023 г. от 16:00 ч. в зала 403 и онлайн в Zoom: \nДоклад на тема \n\nValuations of Higher Rank\nще изнесе Андрей Бенгуш-Ласние\, Международен център по математически науки (МЦМН – София). \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-5/
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:20231206T160000
DTEND;TZID=Europe/Sofia:20231206T173000
DTSTAMP:20260419T235556
CREATED:20231130T142439Z
LAST-MODIFIED:20231130T142439Z
UID:15607-1701878400-1701883800@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 6 декември 2023 г. от 16:00 ч. в зала 403 и онлайн в Zoom: \nДоклад на тема \n\nIntroduction to tropical modifications (II)\nще изнесе Никита Калинин\, Международен център по математически науки (МЦМН – София). \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-4/
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:20231122T160000
DTEND;TZID=Europe/Sofia:20231122T173000
DTSTAMP:20260419T235556
CREATED:20231121T164225Z
LAST-MODIFIED:20231121T164225Z
UID:15481-1700668800-1700674200@math.bas.bg
SUMMARY:Семинар по геометрия на МЦМН
DESCRIPTION:Следващата сбирка на Семинара по геометрия на МЦМН\nще се проведе в сряда\, 22 ноември 2023 г. от 16:00 ч. в зала 403 и онлайн в Zoom:\n\n\nTopics in non-archimedean analytic geometry (II)\n\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-3/
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:20231115T160000
DTEND;TZID=Europe/Sofia:20231115T173000
DTSTAMP:20260419T235556
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
END:VCALENDAR