12 citations · 19 across the 4 of their papers we have counts for
9 papers
On the failure of the first Čech homotopy group to register geometrically relevant fundamental group elements
Jeremy Brazas, Hanspeter Fischer
We construct a space for which the canonical homomorphism from the fundamental group to the first Čech homotopy…
Fibrations, unique path lifting, and continuous monodromy
Hanspeter Fischer, Jacob D. Garcia
Given a path-connected space and , there is essentially only one construction of a map with connected…
Test map characterizations of local properties of fundamental groups
Jeremy Brazas, Hanspeter Fischer
Local properties of the fundamental group of a path-connected topological space can pose obstructions to the applicability of covering space theory. A generalized covering map is a…
Cotorsion-free groups from a topological viewpoint
Katsuya Eda, Hanspeter Fischer
We present a characterization of cotorsion-free abelian groups in terms of homomorphisms from fundamental groups of Peano continua, which aligns naturally with the generalization o…
Word calculus in the fundamental group of the Menger curve
Hanspeter Fischer, Andreas Zastrow
The fundamental group of the Menger universal curve is uncountable and not free, although all of its finitely generated subgroups are free. It contains an isomorphic copy of the fu…
A core-free semicovering of the Hawaiian Earring
Hanspeter Fischer, Andreas Zastrow
The connected covering spaces of a connected and locally path-connected topological space can be classified by the conjugacy classes of those subgroups of which cont…