MathDB
IMC 2010 Problem 3, Day 2

Source:

July 27, 2010
group theoryabstract algebrainductionstrong inductionsuperior algebrasuperior algebra unsolved

Problem Statement

Denote by SnS_n the group of permutations of the sequence (1,2,,n).(1,2,\dots,n). Suppose that GG is a subgroup of Sn,S_n, such that for every πG{e}\pi\in G\setminus\{e\} there exists a unique k{1,2,,n}k\in \{1,2,\dots,n\} for which π(k)=k.\pi(k)=k. (Here ee is the unit element of the group Sn.S_n.) Show that this kk is the same for all πG{e}.\pi \in G\setminus \{e\}.