On the proof of a theorem of Pálfy. (English) Zbl 1112.20004
Summary: P. P. Pálfy [Eur. J. Comb. 8, 35-43 (1987; Zbl 0614.05049)] proved that a group \(G\) is a CI-group if and only if \(|G|=n\) where either \(\gcd(n,\varphi(n))=1\) or \(n=4\), where \(\varphi\) is Euler’s phi function. We simplify the proof of “if \(\gcd(n,\varphi(n))=1\) and \(G\) is a group of order \(n\), then \(G\) is a CI-group”.
MSC:
| 20B25 | Finite automorphism groups of algebraic, geometric, or combinatorial structures |
| 05C25 | Graphs and abstract algebra (groups, rings, fields, etc.) |
| 20D60 | Arithmetic and combinatorial problems involving abstract finite groups |
