Семинар на МЦМН

Институт по математика и информатика - БАН Block 8, 1113 БАН IV км., София

Семинар на МЦМН Вторник, 4.11.2025, 13:00 ч., Зала 403, ИМИ - БАН Лектор: Leonardo Cavenaghi (МЦМН, ИМИ - БАН) Тема на доклада: Exotic phenomena in topology and geometry   Резюме: This talk, aimed at a general audience of mathematicians, discusses very geometric models of exotic spheres. Exotic spheres are manifolds homeomorphic to classical spheres but not diffeomorphic to them. We will outline some constructions via group actions and discuss their admissible geometries. For instance, until this day, it is not known whether an exotic sphere admits a metric of positive sectional curvature, but some do not even admit positive scalar curvature. In this talk, we also outline how one can indirectly study their geometries, aiming to gain a better understanding of their admissible geometries, [...]

Съвместно заседание на Семинара по особености и Семинара на МЦМН

Институт по математика и информатика - БАН Block 8, 1113 БАН IV км., София

Joint meeting of the Seminar on Singularities and the ICMS Seminar, with a lecture by Pablo Cuadrado. The program is as follows. Tuesday, November 18, room 403, IMI-BAS. 13:00 -- Giovane Galindo (ICMS, IMI-BAS) Bundle-type sub-Riemannian structures on holonomy bundles 14:00 -- Pablo Portilla Cuadrado (Universidad Politécnica de Madrid) The medial axis of the Milnor fiber Abstract (Galindo): In this talk we present the notion of Gromov-Hausdorff distance, a novel field of study that aims to understand the topology of the moduli space of Riemannian metrics on a given manifold. We will then present new results on the subject concerning the collapse of principal bundles onto reductive homogeneous spaces. Abstract (Cuadrado): Let f(x,y) define an isolated singularity at the origin. In this talk we explore a [...]

Семинар на МЦМН

Институт по математика и информатика - БАН Block 8, 1113 БАН IV км., София

Вторник, 25 ноември 2025 г., 13:00, room 403, IMI-BAS. Deepanshu Prasad (МЦМН, ИМИ - БАН) An Extension of Sato-Kimura Theorem for Semi-invariant rings Резюме: We give an analog of a result of Sato-Kimura in the context of a semi-invariant  ring for a finite dimensional algebra over an algebraically closed field K of characteristics 0. Then, we examine the case of finite dimensional hereditary algebras over K. This is joint work with Charles Paquette and David Wehlau. https://icms.bg/an-extension-of-sato-kimura-theorem-for-semi-invariant-rings-icms-seminar-talk-by-deepanshu-prasad/

Съвместно заседание на семинара на МЦМН и семинара на секция МОИ

Институт по математика и информатика - БАН Block 8, 1113 БАН IV км., София

26 ноември 2025 г., сряда, от 16:00 ч. в Зала 403 на ИМИ - БАН. Съвместно заседание на Семинара на МЦМН и Семинара на секция Математически основи на информатиката Frank Vallentin (Universität zu Köln) Least distortion Euclidean embeddings of flat tori Резюме: In the emerging field of bi-Lipschitz invariant theory, one studies embeddings of orbit spaces H/G (H a Hilbert space, G a subgroup of its automorphisms) into simpler Hilbert spaces via distance-preserving maps up to a constant factor. In this talk, I present an infinite-dimensional semidefinite program that computes least-distortion embeddings of flat tori Rn/L, where L is an n-dimensional lattice, into Hilbert spaces. Using symmetry reduction techniques, this infinite-dimensional semidefinite program reduces to an infinite-dimensional linear program. Even with this simplification, solving the [...]

Семинар на МЦМН и съвместно заседание със семинара АГТ

Институт по математика и информатика - БАН Block 8, 1113 БАН IV км., София

Следващото заседание на семинара на МЦМН ще се състои във вторник, 2 декември 2025 г. Доклади ще изнесат Рой Маген от МЦМН и Ливиу Орнеа от Букурещския университет, като вторият доклад е в рамките на съвместно заседание със семинара на секция "Анализ, Геометрия и Топология". Програмата е следната. ICMS Seminar and AGT Seminar Tuesday, December 2nd, room 403 IMI-BAS. 13:00 -- Roy Magen (ICMS, IMI-BAS)  Flavours of homotopy theory 14:00 -- Liviu Ornea (University of Bucarest)  Distinguished non-Kähler metrics on compact complex manifolds Abstract (Magen):    In this talk we will consider different flavours of homotopy theory for different types of geometric contexts. First we will recall the usual definitions of the homotopy category, and equivariant homotopy categories, and we will show how we can think of these in [...]

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