Andrew Krenz

I'm a grad student at the University of Wisconsin-Madison. I studied math at Purdue University from 2014-2018. My thesis advisor is Tullia Dymarz. You can contact me at

Research Interests

I'm interested in group homology, coarse homology theories, applications of groupoids to group theory, hyperbolic geometry and hyperbolic groups.


Term Course
Fall 2018 Math 221: Calculus 1
Spring 2019 Math 221 (TA coordinator)
Fall 2019 Math 234: Multivariable Calculus (TA coordinator)
Spring 2020 Math 222: Calculus 2 (TA coordinator)
Summer 2020 Math 221

Here are some notes I took while studying over the past few years. I tried to draw pitures whenever possible. Sorry if there are any errors.


Group Theory Cyclotomic Extensions of Q Commutative Rings

Hatcher: Algebraic Topology

Covering Spaces RP^n Sticky Notes

Algebraic Topology Qual

Problems More Problems Manifold type problems An old qual

Bridson & Haefliger: Metric Spaces of Nonpositive Curvature

Approximate Midpoints Alexandrov's Lemma Comparison Triangles Rectifiable Paths Normed Vector Spaces

Higgins: Categories & Groupoids

Chapter 1 Chapter 6