2009/07/06 by Harper, Eric, Saveliev, Nikolai
#57M05 #57M25 #FOS: Mathematics #Geometric Topology (math.GT)
paper · doi:10.48550/arxiv.0907.1070
We define an integer valued invariant for two-component links in S3 by counting projective SU(2) representations of the link group having non-trivial second Stiefel-Whitney class. We show that our invariant is, up to sign, the linking number of the link. Our construction generalizes that of X.-S. Lin who defined a similar invariant for knots in S3; his invariant equals half the knot signature.