let O be set ; :: thesis: for G being GroupWithOperators of O
for N1, N2 being strict normal StableSubgroup of G holds the carrier of (N1 "\/" N2) = N1 * N2
let G be GroupWithOperators of O; :: thesis: for N1, N2 being strict normal StableSubgroup of G holds the carrier of (N1 "\/" N2) = N1 * N2
let N1, N2 be strict normal StableSubgroup of G; :: thesis: the carrier of (N1 "\/" N2) = N1 * N2
N1 * N2 = N2 * N1 by Th28;
hence the carrier of (N1 "\/" N2) = N1 * N2 by Th30; :: thesis: verum