Vanishing of Hochschild cohomology for affine group schemes and rigidity of homomorphisms between algebraic groups
Documenta mathematica, Tome 14 (2009), pp. 653-672
Let k be an algebraically closed field. If G is a linearly reductive k-group and H is a smooth algebraic k-group, we establish a rigidity property for the set of group homomorphisms G→H up to the natural action of H(k) by conjugation. Our main result states that this set remains constant under any base change K/k with K algebraically closed. This is proven as consequence of a vanishing result for Hochschild cohomology of affine group schemes.
Classification :
20G05
Mots-clés : representations, deformation theory, group schemes, linearly reductive group
Mots-clés : representations, deformation theory, group schemes, linearly reductive group
@article{10_4171_dm_284,
author = {Benedictus Margaux},
title = {Vanishing of {Hochschild} cohomology for affine group schemes and rigidity of homomorphisms between algebraic groups},
journal = {Documenta mathematica},
pages = {653--672},
year = {2009},
volume = {14},
doi = {10.4171/dm/284},
url = {http://geodesic.mathdoc.fr/articles/10.4171/dm/284/}
}
TY - JOUR AU - Benedictus Margaux TI - Vanishing of Hochschild cohomology for affine group schemes and rigidity of homomorphisms between algebraic groups JO - Documenta mathematica PY - 2009 SP - 653 EP - 672 VL - 14 UR - http://geodesic.mathdoc.fr/articles/10.4171/dm/284/ DO - 10.4171/dm/284 ID - 10_4171_dm_284 ER -
Benedictus Margaux. Vanishing of Hochschild cohomology for affine group schemes and rigidity of homomorphisms between algebraic groups. Documenta mathematica, Tome 14 (2009), pp. 653-672. doi: 10.4171/dm/284
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