STATE MODELS FOR KNOT POLYNOMIALS AN INTRODUCTION.

This paper is an unpublished version of a talk that the author gave in Brazil in 1987 at a meeting of the Brazilian Mathematical Society, while visiting Sostenes Lins in Recife, Brazil. The paper is an introduction to state models for link invariants, and it gives a surface-genus interpretation of the extreme terms in the bracket polynomial. [ABSTRACT FROM AUTHOR]