Intrinsic linking and knotting in virtual spatial graphs

Thomas Fleming, Blake Mellor
2007 Algebraic and Geometric Topology  
We introduce a notion of intrinsic linking and knotting for virtual spatial graphs. Our theory gives two filtrations of the set of all graphs, allowing us to measure, in a sense, how intrinsically linked or knotted a graph is; we show that these filtrations are descending and non-terminating. We also provide several examples of intrinsically virtually linked and knotted graphs. As a byproduct, we introduce the virtual unknotting number of a knot, and show that any knot with non-trivial Jones polynomial has virtual unknotting number at least 2.
doi:10.2140/agt.2007.07.583 fatcat:pbq3jjm5mzhdfpy4riobpgycmu