The group of all bijections of {1,…,n} under composition, order n!. Cayley: every finite group embeds in some S_n. A_n is simple for n ≥ 5 — the genesis of unsolvability of the quintic.
The group of all bijections of {1,…,n} under composition, order n!. Cayley: every finite group embeds in some S_n. A_n is simple for n ≥ 5 — the genesis of unsolvability of the quintic.