On $γ$-vectors and the derivatives of the tangent and secant functions

Abstract: In this paper we consider the gamma-vectors of the types A and B Coxeter complexes as well as the gamma-vectors of the types A and B associahedrons. We show that these gamma-vectors can be obtained by using derivative polynomials of the tangent and secant functions. A grammatical description for these gamma-vectors is discussed. Moreover, we also present a grammatical description for the well known Legendre polynomials and Chebyshev polynomials of both kinds.