The International Center for Mathematical Sciences – Sofia (ICMS-Sofia) presents Recent Developments on Tropical Sandpiles and Related Subjects Tuesday, 23 September and Thursday, 25 September 2025 ICMS-Sofia, Room 403 and via Zoom You may find the details here: https://icms.bg/recent-developments-on-tropical-sandpiles-and-related-subjects/ In addition, we plan to have a “round table” meeting at room 378 on Wednesday, September 24, at 14:00, to openly exchange ideas while enjoying drinks and snacks.

A meeting of the ICMS seminar will be held on May 13, 2205, at 2:00 pm, in Room 403 of IMI - BAS. Speaker: Milan Zlatanovic (University of Niš) Title: Non-symmetric gravitational theorys Abstract: We will consider a connection with totally skew-symmetric torsion on non-symmetric (semi-) Riemann manifolds that satisfy Einstein’s metric condition (EMC). We proved that an almost Hermitian manifold is a non-symmetric Riemann manifold that satisfies EMC if and only if it is a Nearly Kahler manifold. We will also show what happens in the case of para Hermitian manifold, contact, and para-contact manifolds that satisfy EMC. We show that a connection with skew symmetric torsion satisfying EMC exists on an almost contact metric manifolds when it is D-homothetic to a cosymplectic manifold. [...]

Time: April 11, 2025, 4:00 pm Place: Room 403, IMI - BAS Speaker: Felipe Espreafico Guelerman, Sorbonne Université - Paris Title: On Motivic and Arithmetic Donaldson-Thomas invariants Further information: https://icms.bg/category/icms-seminar/ Abstract. Aiming to understand the relation to other "refined invariants", and especially their possible interpretation in quantum theory, we explain how to obtain a quadratic, A1-version of Donaldson-Thomas invariants from the motivic refinements first introduced in Kontsevich-Soibelman. Following ideas from Behrend, Bryan and Szendroi, we provide predictions for these invariants in a few simple examples, mainly the computation of DT invariants of A3. Our main goal is to draw relationships with the literature, including works of Levine, Denef and Loser, Azouri, Pepin-Lehaulleur, Srinivas among others. We begin with a brief introduction to A1-enumerative geometry [...]

Time: March 27, 2025, 4:00 pm Place: Room 403, IMI - BAS Speaker: Luis Ugarte (University of Zaragoza, Spain) Title: Complex structures on Lie algebras and its application to the Hull-Strominger system Further information: https://icms.bg/category/icms-seminar/ Abstract. In this talk we will explain the role that the Lie algebras play in the construction of 6-dimensional compact quotient spaces M=G/Γ, where Γ is a lattice, endowed with an invariant complex structure with holomorphically trivial canonical bundle.We will use the approach of stable forms in six dimensions to provide a classification of unimodular Lie algebras admitting a complex structure with non-zero closed (3,0)-form. Some of these spaces can be equipped with balanced Hermitian metrics and they provide invariant solutions of the Hull-Strominger system, even with non-flat connection [...]