Simple groups

A finite group G is simple if it has only two normal subgroups - the trivial group and G itself. Simple groups are building blocks for all finite groups, via extensions, and they are divided into cyclic groups of prime order and the non-abelian simple groups, the 'interesting ones', listed below. For small orders they are all alternating or linear.

See also almost simple, quasisimple and non-soluble groups.

Groups of order 60

A5Alternating group on 5 letters; = SL2(𝔽4) = L2(5) = L2(4) = icosahedron/dodecahedron rotations; 1st non-abelian simple53+A560,5

Groups of order 168

GL3(𝔽2)General linear group on 𝔽23; = Aut(C23) = L3(2) = L2(7); 2nd non-abelian simple73GL(3,2)168,42

Groups of order 360

A6Alternating group on 6 letters; = PSL2(𝔽9) = L2(9); 3rd non-abelian simple65+A6360,118