Category Archives: topological fundamental group

The “tau topology” on the fundamental group

Posted on November 9, 2024 by Jeremy Brazas

In the multipart series on topologies on fundamental groups, we’ve discussed the fundamental group with the quotient topology: . This is defined as having the quotient topology with respect to the map , that identifies homotopic loops. Here, is the … Continue reading →

Posted in Category Theory, coreflection functor, Fundamental group, Quasitopological groups, quasitopological groups, quotient topology, reflection functor, topological fundamental group, Topological groups, Uncategorized | Tagged , , , , , , | 1 Comment

Topologized Fundamental Groups: The Quotient Topology Part 4 (Subgroup Classifications)

Posted on October 7, 2023 by Jeremy Brazas

This is the last in a sequence of posts about the quotient topology. This one is about how the topological structure of can be used to classify certain generalizations of covering maps for locally complicated spaces. Sometimes it still amazes … Continue reading →

Posted in Algebraic Topology, core of a subgroup, Fundamental group, Generalized covering space theory, Griffiths twin cone, harmonic archipelago, Quasitopological groups, quotient topology, semicovering, topological fundamental group, Uncategorized | 7 Comments

Topologized Fundamental Groups: The Quotient Topology Part 3 (Why isn’t it always a topological group?)

Posted on April 18, 2023 by Jeremy Brazas

In Part 1, I mentioned that one of the surprising things about the natural quotient topology on the fundamental group is that the resulting group with topology often fails to be a topological group. In fact, I’d say it’s usually … Continue reading →

Posted in compact-open topology, earring group, Free groups, Fundamental group, quotient topology, topological fundamental group, Topological groups, Uncategorized | Tagged , , , , , , , , , , | 5 Comments