4 papers
An Orientation-Sensitive Vassiliev Invariant for Virtual Knots
J. Sawollek
It is an open question whether there are Vassiliev invariants that can distinguish an oriented knot from its inverse, i.e., the knot with the opposite orientation. In this article,…
On a Planarity Criterion Coming from Knot Theory
J. Sawollek
A graph G is called "minimalizable" if a diagram with minimal crossing number can be obtained from an arbitrary diagram of G by crossing changes. If, furthermore, the minimal diagr…
On Alexander-Conway Polynomials for Virtual Knots and Links
J. Sawollek
A polynomial invariant of virtual links, arising from an invariant of links in thickened surfaces introduced by Jaeger, Kauffman, and Saleur, is defined and its properties are inve…
Tait's Flyping Conjecture for 4-Regular Graphs
J. Sawollek
Tait's flyping conjecture, stating that two reduced, alternating, prime link diagrams can be connected by a finite sequence of flypes, is extended to reduced, alternating, prime di…