© 1997 by London Mathematical Society
© The London Mathematical Society
Combinatorial Expansions of KazhdanLusztig Polynomials
School of Mathematics, Institute for Advanced Study Princeton, New Jersey 08540, USA
Received 9 January 1995.
We introduce two related families of polynomials, easily computable by simple recursions into which any KazhdanLusztig (and inverse KazhdanLusztig) polynomial of any Coxeter group can be expanded linearly, and we give combinatorial interpretations to the coefficients in these expansions. This yields a combinatorial rule for computing the KazhdanLusztig polynomials in terms of paths in a directed graph, and a completely combinatorial reformulation of the nonnegativity conjecture [15, p. 166].