let R be Skew-Field; :: thesis: for V being LeftMod of R
for A being Subset of V st Lin A = V holds
ex I being Basis of V st I c= A

let V be LeftMod of R; :: thesis: for A being Subset of V st Lin A = V holds
ex I being Basis of V st I c= A

let A be Subset of V; :: thesis: ( Lin A = V implies ex I being Basis of V st I c= A )
assume Lin A = V ; :: thesis: ex I being Basis of V st I c= A
then consider B being Subset of V such that
A1: B c= A and
A2: B is base by Th19;
reconsider B = B as Basis of V by A2;
take B ; :: thesis: B c= A
thus B c= A by A1; :: thesis: verum