Nagoya Mathematical Journal

Lusztig's $a$-function in type $B_{n}$ in the asymptotic case

Meinolf Geck and Lacrimioara Iancu

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In this paper, we study Lusztig's ${\mathbf{a}}$-function for a Coxeter group with unequal parameters. We determine that function explicitly in the "asymptotic case" in type $B_{n}$, where the left cells have been determined in terms of a generalized Robinson-Schensted correspondence by Bonnafé and the second author. As a consequence, we can show that all of Lusztig's conjectural properties (P1)--(P15) hold in this case, except possibly (P9), (P10) and (P15). Our methods rely on the "leading matrix coefficients" introduced by the first author. We also interprete the ideal structure defined by the two-sided cells in the associated Iwahori-Hecke algebra ${\mathcal{H}}_{n}$ in terms of the Dipper-James-Murphy basis of ${\mathcal{H}}_{n}$.

Article information

Nagoya Math. J., Volume 182 (2006), 199-240.

First available in Project Euclid: 20 June 2006

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Mathematical Reviews number (MathSciNet)

Zentralblatt MATH identifier

Primary: 20C08: Hecke algebras and their representations
Secondary: 20G40: Linear algebraic groups over finite fields


Geck, Meinolf; Iancu, Lacrimioara. Lusztig's $a$-function in type $B_{n}$ in the asymptotic case. Nagoya Math. J. 182 (2006), 199--240.

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