Lower and Upper Bounds for Positive Bases of Skein Algebras

Abstract

We show that the if a sequence of normalized polynomials gives rise to a positive basis of the skein algebra of a surface, then it is sandwiched between the two types of Chebyshev polynomials. For the closed torus, we show that the normalized sequence of Chebyshev polynomials of type one $({\hat{T}}_n)$ is the only one which gives a positive basis.

12 pages, 5 figures