The Seminar for Combinatorics, Geometry, Topology and Algebra (CGTA) was created spontaneously by a group of Belgrade mathematicians with different mathematical backgrounds around 1985. This group was initially formed by Sava Krstić (Math. Institute SANU)), Aleksandar Lipkovski (Belgrade Univ.), Aleksandar Vucić (Belgrade Univ.), Siniša Vrećica (Belgrade Univ.) and Rade Živaljević (Math. Inst. SANU). Over the years the seminar worked continuously and attracted some of the most talented young Yugoslav mathematicians. Among the visitors and friends of the seminar we acknowledge the special contribution of Jurij Petrovic Solovjov, professor of the Moscow State University (MGU).
Over the years the seminar and the associated GTA graduate courses covered numerous topics, including: the theory of Lie groups, algebraic curves, dihedral and cyclic homology, theory of group actions, Borsuk-Ulam type theorems and applications, discrete and computational geometry, automorphisms of free groups, hyperplane arrangements, stable homotopy theory, knot invariants and others. Currently the topics that receive the most attention are the applications of topological methods in combinatorics and combinatorial geometry, the theory of convex polytopes and algebraic geometry (toric varieties, Newton polyhedra), arrangements of hyperplanes, Goresky-MacPherson type formulas, knot invariants, configuration spaces, and three manifolds.
The program of the seminar keeps changing but two characteristics are preserved. The seminar emphasizes the interplay of ideas from different mathematical fields affirming the unity of mathematics. A coffee maker (a souvenir from the Givat Ram University) and occassional light refreshments provide an informal and friendly atmosphere in the seminar to encourage the creative exchange of ideas.