Strong Approximate Innerness for Diagonal Graph Actions without Aperiodicity
Manuscript 18 October 2026 · Online 18 October 2026
Abstract
Every finite abelian action on the C*-algebra of a finite strongly connected noncycle graph that fixes vertices and scales edges by characters is strongly approximately inner. Neither graph aperiodicity nor action outerness is assumed. The proof uses Barlak and Szabo's aperiodic outer-action theorem as its analytic input, removes the graph period through a return-path corner and fixed-frame lifting, and removes the inner kernel through vertex coboundaries and extension of subgroup characters. A block-diagonal polar correction restores fixed implementers for the original action. The result answers the finite abelian diagonal quasi-free action question in Oberwolfach Report 42/2017, p. 2621, for simple purely infinite Cuntz-Krieger algebras. This is an AI-assisted, self-audited, unrefereed preprint; no formal verification, independent human review or absolute priority is claimed.
Record
- Affiliation
- Mercury Software GmbH
- Contact
- [email protected] · GitHub
- Result
- Complete affirmative proof
- Categories
- math.OA
- Manuscript
- 18 October 2026
- Online release
- 18 October 2026
- Version
- 1.0
- License
- Creative Commons Attribution 4.0 International
Files and verification
The PDF is the canonical reading copy. The source archive contains the LaTeX manuscript, bibliography, reproducibility material, and audit documents without build artefacts.
Citation
Alper Ferudun, “Strong Approximate Innerness for Diagonal Graph Actions without Aperiodicity,” EulerSolve Research Papers, OWR-15585-006, 2026. https://doi.org/10.5281/zenodo.23443694.
BibTeX
@misc{ferudun2026diagonalgraph,
author = {Ferudun, Alper},
title = {Strong Approximate Innerness for Diagonal Graph Actions without Aperiodicity},
year = {2026},
howpublished = {EulerSolve Research Papers},
url = {https://eulersolve.org/papers/owr-15585-006/},
doi = {10.5281/zenodo.23443694},
note = {OWR-15585-006; unrefereed preprint}
}