A finite three-ample complex with a nontrivial fundamental group
Recorded by the registry's curators from GitHub; the authors did not submit it here.
Kaiwen Jin
We construct a finite three-ample simplicial complex on $32{,}768$ vertices which retracts simplicially onto a four-cycle. Thus the prescribed extension of every subcomplex on at most three vertices is compatible with a nontrivial fundamental group in a finite complex. The construction fixes a four-cycle and chooses the remaining permitted faces probabilistically. A finite union bound proves that all extension requests can be met at once.
Claims
Files and sources
- Paper
- AIM @ 24edaad, paper/finite_three_ample.pdf ↗
- Posted on GitHub
- 14 October 2026
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