reconsider g = <*2,1*> as Permutation of (Seg 2) by Lm2, MATRIX_2:def 11;
for l being FinSequence of (Group_of_Perm 2) holds
( not (len l) mod 2 = 0 or not g = Product l or ex i being Nat st
( i in dom l & ( for q being Element of Permutations 2 holds
( not l . i = q or not q is being_transposition ) ) ) ) by Lm1, MATRIX_7:11;
then not g is even by MATRIX_2:def 15;
hence not for b₁ being Permutation of (Seg 2) holds b₁ is even ; :: thesis: verum