USA Topology Seminar
On a topological interpretation of quandle cocycle invariants of classical links
Takefumi Nosaka, Kyoto University
Thursday, October 13, 2011
S. Carter and M. Saito et al. introduced quandle cocycle invariants of classical links using quandle 2-cocycles with local coefficients. However the construction is combinatorial, using link-diagrams. In this talk, for "some" quandles, we give a topological interpretation of all quandle cocycle invariants. The basic idea is to observe the cocycle invariants from "link bordism groups of X-colorings", and to relate the bordism group to a group homology via branched covering spaces.