29 citations · 167 across the 26 of their papers we have counts for
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math.GR2005
Homotopy formulas for cyclic groups acting on rings
Christian Kassel
The positive cohomology groups of a finite group acting on a ring vanish when the ring has a norm-one element. In this note we give explicit homotopies on the level of cochains whe…
math.QA2005
Quantum principal bundles up to homotopy equivalence
Christian Kassel
We translate some fundamental properties satisfied by topological principal bundles into the setting of Hopf-Galois extensions. The properties are: functoriality, homotopy, and tri…
math.GR2005★ 27 cited
Sturmian morphisms, the braid group B_4, Christoffel words and bases of F_2
Christian Kassel, Christophe Reutenauer
We give a presentation by generators and relations of a certain monoid generating a subgroup of index two in the group Aut(F_2) of automorphisms of the rank two free group F_2 and…