The next meeting of the Joint Seminar of Analysis, Geometry and Topology Department will be held on April 28, 2022 at 1:00 pm (UTC+3)  in Room 478 of IMI. A talk on: Isotropic Killing vector fields and structures on complex surfaces  will be delivered by Gueo Grantcharov, Florida International University, USA. Everybody is invited. Abstract. In a 4-dimensional vector space with scalar product of signature (2,2), two independent vectors spanning a maximal isotropic (null) plane determine a canonical action of the para-quaternioins. We noticed that on an oriented 4-manifold with such pseudo-Riemannian metric, existence of two isotropic (null) Killing vector fields leads to integrability of the induced structure - called para-hypercomplex, and the metric is anti-selfdual. Using the Kodaira classification one can describe the [...]

The next meeting of the Joint Seminar of Analysis, Geometry and Topology Department will be held on March 29, 2022, at 1:30 pm (UTC+2) in Room 478 of IMI-BAS.. A talk on: On Squeezing Function for Planar Domains will be delivered by Ahmed Yekta Ökten, Institut de Mathématiques de Toulouse, France. Everybody is invited. Abstract. Let Ω be a domain in ℂ𝑛 such that the set 𝐸(Ω, 𝐵𝑛) of injective holomorphic maps from Ω into the unit ball 𝐵𝑛 ⊂ ℂ𝑛 is non-empty. The squeezing function of Ω, denoted by 𝑆Ω is defined as 𝑆Ω(𝑧) = sup{𝑟 ∈ (0, 1): 𝑟𝐵𝑛 ⊂ 𝑓(Ω),      𝑓 ∈ 𝐸(Ω, 𝐵𝑛),      𝑓 (𝑧) = 0}. It follows from the definition that the squeezing function is biholomorphically [...]

The next meeting of the Joint Seminar of Analysis, Geometry and Topology Department will be held on February 15, 2022, at 1:00 pm (UTC+2) via Zoom. A talk on: Kähler Manifolds of Quasi-constant Holomorphic Sectional Curvature and Generalized Sasakian Space Forms will be delivered by Cornelia-Livia Bejan,  “Gheorghe Asachi” Technical University of Iasi, Romania. Everybody is invited. Abstract. Two geometric notions, namely Kähler manifolds of quasi-constant holomorphic sectional curvature and generalized Sasakian space forms, are related to each other, for the first time. Some conditions under which each of these structures induces the other one, are provided here. Several results are obtained on direct products (which are special cases of Naveira’s classification), warped products or hypersurfaces of manifolds and relevant examples are included. A result [...]

The next meeting of the Joint Seminar of Analysis, Geometry and Topology Department will be held on  December 14, 2021 at 1:00 p.m. (GMT+2:00) via Zoom. A talk on: Towards Homological Mirror Symmetry for weighted projective planes over the complex numbers will be delivered by: Marin Genov. Everybody is invited. Join Zoom link: https://miami.zoom.us/j/93060507383?pwd=Y2MremVpcmJrdkRiN3N3QVVZZC9HQT09 Meeting ID: 930 6050 7383 Passcode: 825839  

The next meeting of the Joint Seminar of Analysis, Geometry and Topology Department will be held online on  October 19, 2021 at 2:00 p.m. (GMT+3:00). A talk on: Index counting theories and  linear stability of  periodic waves will be delivered by: Sevdzhan Hakkaev, Shumen University. Everybody is invited. Abstract. In this talk, we will present some results on the stability of periodic waves. In the models that we will consider, stability problem leads to the study of the spectral problems of the form and computations of the quantities involved in the stability index. Contact : V. Milousheva, vmil@math.bas.bg Join Zoom link: https://us02web.zoom.us/j/83064361660?pwd=T2tJVmswdFgzWmdUYkdWQWtUM3owQT09 Meeting ID: 830 6436 1660 Passcode: 453424  

The next meeting of the Joint Seminar of Analysis, Geometry and Topology Department will be held on June 22, 2021, from 11:30 via Zoom. A talk on: General Rotational Surfaces in Pseudo-Euclidean 4-Spaces will be delivered by: Victoria Bencheva. Everybody is invited. Abstract. Rotational surfaces are rich source of examples both in Euclidean and pseudo-Euclidean spaces. We consider the so-called general rotational surfaces of elliptic and hyperbolic type in the Minkowski 4-space and the pseudo-Euclidean 4-space with neutral metric which are analogous to the general rotational surfaces introduced by C. Moore in the Euclidean space R^4. We describe analytically some basic subclasses of general rotational surfaces, namely: minimal, flat, with flat normal connection, with parallel normalized mean curvature vector field. Topic: Общ семинар на [...]