let X be non empty set ; ( dom (canon_image (X,1)) = X & ( for x being set st x in X holds
(canon_image (X,1)) . x = [x,1] ) )
dom (canon_image (X,1)) = free_magma (X,1)
by FUNCT_2:def 1;
hence
dom (canon_image (X,1)) = X
by Def13; for x being set st x in X holds
(canon_image (X,1)) . x = [x,1]
hence
for x being set st x in X holds
(canon_image (X,1)) . x = [x,1]
by Def19; verum