activity
20082018
most citedThe third cohomology group classifies crossed module extensions

3 citations · 5 across the 6 of their papers we have counts for

collaborators

6 papers

math.CT2018

Equivalences between localisations of categories provided by replacements

Sebastian Thomas

We give a characterisation of functors whose induced functor on the level of localisations is an equivalence and where the isomorphism inverse is induced by some kind of replacemen…

math.CT2010★ 1 cited

On the 3-arrow calculus for homotopy categories

Sebastian Thomas

We develop a localisation theory for certain categories, yielding a 3-arrow calculus: Every morphism in the localisation is represented by a diagram of length 3, and two such diagr…

math.AT2009

On the second cohomology group of a simplicial group

Sebastian Thomas

We give an algebraic proof for the result of Eilenberg and Mac Lane that the second cohomology group of a simplicial group G can be computed as a quotient of a fibre product involv…

math.KT2009★ 3 cited

The third cohomology group classifies crossed module extensions

Sebastian Thomas

We give an elementary proof of the well-known fact that the third cohomology group H^3(G, M) of a group G with coefficients in an abelian G-module M is in bijection to the set Ext^…

math.AT2009

Faithfulness of a functor of Quillen

William G. Dwyer, Andrei Radulescu-Banu, Sebastian Thomas

There exists a canonical functor from the category of fibrant objects of a model category modulo cylinder homotopy to its homotopy category. We show that this functor is faithful u…

math.AT2008★ 1 cited

The functors Wbar and Diag o Nerve are simplicially homotopy equivalent

Sebastian Thomas

Given a simplicial group G, there are two known classifying simplicial set constructions, the Kan classifying simplicial set Wbar G and Diag N G, where N denotes the dimensionwise…