1 results
A 3-Dimensional Non-Abelian Cohomology of Groups With Applications to Homotopy Classification of Continuous Maps
-
- Journal:
- Canadian Journal of Mathematics / Volume 43 / Issue 2 / 01 April 1991
- Published online by Cambridge University Press:
- 20 November 2018, pp. 265-296
- Print publication:
- 01 April 1991
-
- Article
-
- You have access
- Export citation
-
The general problem of what should be a non-abelian cohomology, what is it supposed to do, and what should be the coefficients, form a set of interesting questions which has been around for a long time. In the particular setting of groups, a comprehensible and well motivated cohomology theory has been so far stated in dimensions ≤ 2, the coefficients for
being crossed modules. The main effort to define an appropriate 
for groups has been done by Dedecker [16] and Van Deuren [40]; they studied the obstruction to lifting non-abelian 2-cocycles and concluded with first approach for , which requires “super crossed groups” as coefficients. However, as Dedecker said “some polishing work remains necessary” for his cohomology.
being crossed modules. The main effort to define an appropriate 
for groups has been done by Dedecker [16] and Van Deuren [40]; they studied the obstruction to lifting non-abelian 2-cocycles and concluded with first approach for 