I came across a reference in this MathOverflow answer to an intriguing result of Ulrich Felgner [1]: among finite non-Abelian groups, the property of being simple is first-order definable. According to that answer, he derives it as a consequence of the classification of finite simple groups (which seems very plausible, but tantalising).
I would be interested to see a proof of this result — either Felgner’s original paper [1], or (especially) if there have been any subsequent alternative proofs given, especially not relying on the CFSG. Unfortunately I’ve been unable to access a copy of [1] — I can only find physical holdings at a few libraries in Germany (list on WorldCat) — nor any other presentations of the result. Hence my main question: Can anyone recommend a physically/electronically accessible reference for Felgner’s result? I’d be happy with either Felgner’s original [1] or any subsequent work, and either electronic access or a more widely-distributed physical version.
References:
- Ulrich Felgner, Pseudo-endliche Gruppen. (Pseudofinite groups), MR1107758, Proceedings of the 8th Easter Conference on Model Theory (Wendisch-Rietz, 1990), 82–96, Seminarberichte, 110, Humboldt Univ., Berlin, 1990.
