5 citations · 15 across the 9 of their papers we have counts for
11 papers
A canonical splitting of the first homology group of Peano continua
Gregory R. Conner, Wolfgang Herfort, Curtis Kent +1
The first singular homology of a Peano continuum with torsion-free first Cech homology, , splits as where is the homology s…
A short note on coproducts of abelian pro-Lie groups
Wolfgang Herfort, Karl H. Hofmann, Francesco G. Russo
The notion of conditional coproduct of a family of abelian pro-Lie groups in the category of abelian pro-Lie groups is introduced. It is shown that the cartesian product of an arbi…
Inverse limit slender groups
Gregory Conner, Wolfgang Herfort, Curtis Kent +1
Classically, an abelian group is said to be slender if every homomorphism from the countable product to factors through the projection to some finit…
Uncountable groups and the geometry of inverse limits of coverings
Gregory Conner, Wolfgang Herfort, Curtis Kent +1
In this paper we develop a new approach to the study of uncountable fundamental groups by using Hurewicz fibrations with the unique path-lifting property (lifting spaces for short)…
When is the Sum of Two Closed Subgroups Closed in a Locally Compact Abelian Group
Wolfgang Herfort, Karl H. Hofmann, Francesco G. Russo
Locally compact abelian groups are classified in which the sum of any two closed subgroups is itself closed. This amounts to reproving and extending results by Yu.~N.~Mukhin from 1…
Geometry of compact lifting spaces
Gregory R. Conner, Wolfgang Herfort, Petar Pavešić
We study a natural generalization of inverse systems of finite regular covering spaces. A limit of such a system is a fibration whose fibres are profinite topological groups. Howev…
Some anomalous examples of lifting spaces
Gregory R. Conner, Wolfgang Herfort, Petar Pavešić
An inverse limit of a sequence of covering spaces over a given space is not, in general, a covering space over but is still a lifting space, i.e. a Hurewicz fibration with…
A Study in Locally Compact Groups
Karl H. Hofmann, Wolfgang Herfort, Francesco G. Russo
The class of locally compact near abelian groups is introduced and investigated as a class of metabelian groups formalizing and applying the concept of scalar multiplication. The s…
Setup of Order Conditions for Splitting Methods
Winfried Auzinger, Wolfgang Herfort, Harald Hofstätter +1
This article is based on earlier papers where an approach based on Taylor expansion and the structure of its leading term as an element of a free Lie algebra was described for the…
The BCH-Formula and Order Conditions for Splitting Methods
Winfried Auzinger, Wolfgang Herfort, Othmar Koch +1
As an application of the BCH-formula, order conditions for splitting schemes are derived. The same conditions can be obtained by using non-commutative power series techniques and i…
Splitting theorems for pro- groups acting on pro- trees and 2-generated subgroups of free pro- products with procyclic amalgamations
Wolfgang Herfort, Pavel Zalesskii, Theo Zapata
Let G be a finitely generated infinite pro-p group acting on a pro-p tree such that the restriction of the action to some open subgroup is free. Then we prove that G splits as a pr…