ИСТИНА

Combinatorial approach to knot theory treats knots as diagrams modulo Reidemeister moves. Many constructions of knot invariants (index polynomials, quandle colorings etc.) use elements of diagrams such as arcs and crossings by assigning invariant labels to them. For two diagrams connected by a sequence of Reidemeister moves, one can identify some arcs and crossings of the diagrams. The classes of identified arcs or crossings can be called the arcs and crossings of the knot. In the talk we give a topological description of sets of these classes.