Gerstenhaber-schack and Hochschild cohomologies of Hopf algebras
Documenta mathematica, Tome 21 (2016), pp. 955-986
We show that the Gerstenhaber-Schack cohomology of a Hopf algebra determines its Hochschild cohomology, and in particular its Gerstenhaber-Schack cohomological dimension bounds its Hochschild cohomological dimension, with equality of the dimensions when the Hopf algebra is cosemisimple of Kac type. Together with some general considerations on free Yetter-Drinfeld modules over adjoint Hopf subalgebras and the monoidal invariance of Gerstenhaber-Schack cohomology, this is used to show that both Gerstenhaber-Schack and Hochschild cohomological dimensions of the coordinate algebra of the quantum permutation group are 3.
Classification :
16E10, 16E40, 16T05
Mots-clés : Hopf algebra, cohomological dimension, cohomology, Yetter-Drinfeld module
Mots-clés : Hopf algebra, cohomological dimension, cohomology, Yetter-Drinfeld module
@article{10_4171_dm_550,
author = {Julien Bichon},
title = {Gerstenhaber-schack and {Hochschild} cohomologies of {Hopf} algebras},
journal = {Documenta mathematica},
pages = {955--986},
year = {2016},
volume = {21},
doi = {10.4171/dm/550},
url = {http://geodesic.mathdoc.fr/articles/10.4171/dm/550/}
}
Julien Bichon. Gerstenhaber-schack and Hochschild cohomologies of Hopf algebras. Documenta mathematica, Tome 21 (2016), pp. 955-986. doi: 10.4171/dm/550
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