We recall first some known
facts on Jones and Kauffman polynomials for links, and on state models
for link invariants. We give next an exposition of a recent spin model due
to F. Jaeger and which involves the Higman-Sims graph. The associated
invariant assigns to an oriented link the evaluation for a = −τ5 and z = 1 of its
Kauffman polynomial in the Dubrovnik form, where τ denotes the golden
ratio.