Hodge Operators and Exceptional Isomorphisms between Unitary Groups
Journal of Lie theory, Tome 33 (2023) no. 1, pp. 329-36
We give a generalization of the Hodge operator to spaces (V,h) endowed with a hermitian or symmetric bilinear form h over arbitrary fields, including the characteristic two case. Suitable exterior powers of V become free modules over an algebra K defined using such an operator. This leads to several exceptional homomorphisms from unitary groups (with respect to h) into groups of semi-similitudes with respect to a suitable form over some subfield of K. The algebra K depends on h; it is a composition algebra unless h is symmetric and the characteristic is two.
Classification :
20G15, 20E32, 20G20, 20G40, 22C05, 11E39, 11E57
Mots-clés : Hermitian form, symmetric bilinear form, exterior product, Pfaffian form, Hodge operator, exceptional isomorphism, composition algebra, quaternion algebra
Mots-clés : Hermitian form, symmetric bilinear form, exterior product, Pfaffian form, Hodge operator, exceptional isomorphism, composition algebra, quaternion algebra
@article{JLT_2023_33_1_JLT_2023_33_1_a14,
author = {L. Kramer and M. J. Stroppel},
title = {Hodge {Operators} and {Exceptional} {Isomorphisms} between {Unitary} {Groups}},
journal = {Journal of Lie theory},
pages = {329--36},
year = {2023},
volume = {33},
number = {1},
url = {http://geodesic.mathdoc.fr/item/JLT_2023_33_1_JLT_2023_33_1_a14/}
}
L. Kramer; M. J. Stroppel. Hodge Operators and Exceptional Isomorphisms between Unitary Groups. Journal of Lie theory, Tome 33 (2023) no. 1, pp. 329-36. http://geodesic.mathdoc.fr/item/JLT_2023_33_1_JLT_2023_33_1_a14/