29 citations · 167 across the 26 of their papers we have counts for
5 papers · 1 filter
Braid groups and symplectic Steinberg groups
François Digne, Christian Kassel
We construct a homomorphism from the braid group on strands to the Steinberg group associated with the Lie type and with integer coefficients. This homo…
A braid-like presentation of the integral Steinberg group of type
Christian Kassel
We show that the Steinberg group associated with the Lie type and with integer coefficients can be realized as a quotient of the braid group $B_6…
On an action of the braid group B_{2g+2} on the free group F_{2g}
Christian Kassel
We construct an action of the braid group B_{2g+2} on the free group F_{2g} extending an action of B_4 on F_2 introduced earlier by Reutenauer and the author. Our action induces a…
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…
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…