let V be RealLinearSpace; :: thesis: for A, B being Subset of V
for l being Linear_Combination of A st A c= B holds
l is Linear_Combination of B

let A, B be Subset of V; :: thesis: for l being Linear_Combination of A st A c= B holds
l is Linear_Combination of B

let l be Linear_Combination of A; :: thesis: ( A c= B implies l is Linear_Combination of B )
assume A1: A c= B ; :: thesis: l is Linear_Combination of B
Carrier l c= A by Def6;
then Carrier l c= B by A1;
hence l is Linear_Combination of B by Def6; :: thesis: verum