Undecidability problems for semifree DG algebras
Rings and Algebras
2026-05-12 v1 Geometric Topology
Logic
Symplectic Geometry
Abstract
We prove that the stable tame isomorphism, quasi-isomorphism, and derived Morita equivalence problems for semifree noncommutative differential graded algebras (DGAs) are all undecidable. This resolves half of Problem 5.16 from the K3 Problem List in Low-Dimensional Topology. We present two solutions, both obtained (essentially autonomously) by Gemini Deep Think / Aletheia.
Cite
@article{arxiv.2605.08122,
title = {Undecidability problems for semifree DG algebras},
author = {Ciprian Manolescu and Nick Rozenblyum},
journal= {arXiv preprint arXiv:2605.08122},
year = {2026}
}
Comments
6 pages