Hostname: page-component-848d4c4894-ttngx Total loading time: 0 Render date: 2024-06-08T18:24:30.740Z Has data issue: false hasContentIssue false

Orbital Integrals on p-Adic Lie Algebras

Published online by Cambridge University Press:  20 November 2018

Rebecca A. Herb*
Affiliation:
Department of Mathematics, University of Maryland, College Park, Maryland 20742, U.S.A. email: rah@math.umd.edu
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Let $G$ be a connected reductive $p$-adic group and let $\mathfrak{g}$ be its Lie algebra. Let $\mathcal{O}$ be any $G$-orbit in $\mathfrak{g}$. Then the orbital integral ${{\mu }_{\mathcal{O}}}$ corresponding to $\mathcal{O}$ is an invariant distribution on $\mathfrak{g}$, and Harish-Chandra proved that its Fourier transform ${{\hat{\mu }}_{\mathcal{O}}}$ is a locally constant function on the set ${\mathfrak{g}}'$ of regular semisimple elements of $\mathfrak{g}$. If $\mathfrak{h}$ is a Cartan subalgebra of $\mathfrak{g}$, and $\omega $ is a compact subset of $\mathfrak{h}\,\cap \,{\mathfrak{g}}'$, we give a formula for ${{\hat{\mu }}_{\mathcal{O}}}\left( tH \right)$ for $H\,\in \,\omega $ and $t\,\in \,{{F}^{\times }}$ sufficiently large. In the case that $\mathcal{O}$ is a regular semisimple orbit, the formula is already known by work of Waldspurger. In the case that $\mathcal{O}$ is a nilpotent orbit, the behavior of ${{\hat{\mu }}_{\mathcal{O}}}$ at infinity is already known because of its homogeneity properties. The general case combines aspects of these two extreme cases. The formula for ${{\hat{\mu }}_{\mathcal{O}}}$ at infinity can be used to formulate a “theory of the constant term” for the space of distributions spanned by the Fourier transforms of orbital integrals. It can also be used to show that the Fourier transforms of orbital integrals are “linearly independent at infinity.”

Keywords

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 2000

References

[1] DeBacker, S., On supercuspidal characters of GL l , l a prime. Ph.D. Thesis, The University of Chicago, 1997.Google Scholar
[2] , Harish-Chandra, Admissible invariant distributions on reductive p-adic groups. Notes by S. DeBacker and P. J. Sally, Jr., University Lecture Series 16, Amer. Math. Soc., Providence, RI, 1999.Google Scholar
[3] Huntsinger, R., Some aspects of invariant harmonic analysis on the Lie algebra of a reductive p-adic group. Ph.D. Thesis, The University of Chicago, 1997.Google Scholar
[4] Moy, A. and Prasad, G., Unrefined minimal K-types for p-adic groups. Invent. Math. 116(1994), 393408.Google Scholar
[5] Moy, A. and Prasad, G., Jacquet functors and unrefined minimal K-types. Comment. Math. Helv. 71(1996), 98121.Google Scholar
[6] Murnaghan, F., Characters of supercuspidal representations of SL(n). Pacific J. Math. 170(1995), 217235.Google Scholar
[7] Murnaghan, F., Local character expansions for supercuspidal representations of U(3). Canad. J. Math. 47(1995), 606640.Google Scholar
[8] Murnaghan, F., Characters of supercuspidal representations of classical groups. Ann. Sci. École Norm. Sup. 29(1996), 49105.Google Scholar
[9] Murnaghan, F., Local character expansions and Shalika germs for GL(n). Math. Ann. 304(1996), 423455.Google Scholar
[10] Waldspurger, J.-L., Une formule des traces locale pour les algebres de Lie p-adiques. J. Reine Angew. Math. 465(1995), 4199.Google Scholar
[11] Waldspurger, J.-L., Quelques resultats de finitude concernant les distributions invariantes sur les algebres de Lie p-adiques. preprint.Google Scholar