Postnikov invariants of crossed complexes

Postnikov invariants of crossed complexes

We determine the Postnikov tower and Postnikov invariants of a crossed complex in a purely algebraic way. Using the fact that crossed complexes are homotopy types for filtered spaces, we use the above “algebraically defined” Postnikov tower and Postnikov invariants to obtain from them those of filtered spaces. We argue that a similar “purely algebraic” approach to Postnikov invariants may also ...

Se p 20 04 Postnikov Invariants of Crossed Complexes

We determine the Postnikov Tower and Postnikov Invariants of a Crossed Complex in a purely algebraic way. Using the fact that Crossed Complexes are homotopy types for filtered spaces, we use the above " algebraically defined " Postnikov tower and Postnikov invariants to obtain from them those of filtered spaces. We argue that a similar " purely algebraic " approach to Postnikov invariants may a...

Postnikov “ Invariants ” in 2004

The very nature of the so-called Postnikov invariants is carefully studied. Two functors, precisely defined, explain the exact nature of the connection between the category of topological spaces and the category of Postnikov towers. On one hand, these functors are in particular effective and lead to concrete machine computations through the general machine program Kenzo. On the other hand, the ...

Standard Invariants for Crossed

Crossed complexes, free crossed resolutions and graph products of groups

The category of crossed complexes gives an algebraic model of CW -complexes and cellular maps. Free crossed resolutions of groups contain information on a presentation of the group as well as higher homological information. We relate this to the problem of calculating non-abelian extensions. We show how the strong properties of this category allow for the computation of free crossed resolutions...