Adams completion and Postnikov systems

Postnikov Identities and Seo’s Formulas

Seo and others have generalized an identity of Postnikov by finding expressions for the generating function for the number of proper vertices in certain families of rooted trees and forests. We describe an approach to these results that involves a straightforward inductive argument and a version of the Lambert-Rothe identities.

Homotopy approximation of modules

Deleanu, Frei, and Hilton have developed the notion of generalized Adams completion in a categorical context. In this paper, we have obtained the Postnikov-like approximation of a module, with the help of a suitable set of morphisms.

On the Cohomology of Two-stage Postnikov Systems

On the Cohomology of Stable Two Stage Postnikov Systems

Introduction. Let £ = (£ , p, B, F) denote a two stage Postnikov system with stable fe-invariant. We announce results about H*(ÜE) as a Hopf algebra over the Steenrod algebra. Mod 2 cohomology is used exclusively. Unexplained notation is from [4] and [S]. 1 am grateful to D. Anderson, W. Massey, F . Peterson and H. Salomonsen for many useful remarks. We make the following assumptions on £, in 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 ...