• Theory of graphs: products of graphs and other operations, chemical graph theory, metric graph theory, graph algorithms and some graph invariants
  • Linear Algebra with elements of Functional Analysis: characterizations of linear and general preservers on finite and infinite dimensional algebras
  • Differential equations: qualitative theory of ordinary differential equations, theory of oscillations, theory of invariants


  • Quantum-mechanical numerical calculations
  • Mathematical modeling of complex physical and biological systems.