Mathematics:

• 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

Physics:

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