My research is in topological (Nielsen) fixed point theory and some related areas, and the topological theory of digital images. For an introduction to Nielsen fixed point theory for the general
mathematical audience, try watching my Youtube videos 85 Years of Nielsen Theory.
My Erdős number is 4: Staecker → Gonçalves → Golasiński → Henriksen → Erdős.
All of my papers are available at arXiv. The arXiv versions are essentially identical to the published versions. These are also mirrored at Fairfield University's Digital Commons.
Most of my papers eventually get indexed at MathSciNet and Zentralblatt.
Recent Academic Talks and Presentations
Gerber's Great Graphical Gizmos
A 6 minute talk given at Gathering 4 Gardner 14 in Atlanta, April 8 2022. Accessible to anyone.
Nielsen fixed point theory in classical and digital topology
A series of 3 hour talks given at the Fixed Point Theory Lab, King Mongkut's University of Technology Thonburi, Bangkok Thailand, October 11, 14 & 15, 2019. The first talk requires some basic algebraic topology background, the other two are probably mostly understandable for math undergraduates.
Rotations on graphs and fractional exponents in groups
A 50 minute talk given at the Sogang University Mathematics Colloquium,
Seoul, South Korea, March 23, 2017.
The audience was master's-level mathematics graduate students, but anybody can understand the first 15 minutes or so.
The package above contains some GAP programs which are of more general
foxcalc.gap A basic but
useful implementation of the Fox Derivative
dehn.gap Functions for performing
Dehn's algorithm for the word problem in finitely presented groups,
and some basic functions for verifying small cancellation properties
I have an interest in proof formalization, specifically using the Coq proof assistant, which can produce computer-verifiable proofs of mathematical theorems. You are free to use any of my code subject to the cc-by-sa license.
listlemmas.v A collection of lemmas about lists and sublists.