let F be Field; for V being VectSp of
for W being Subspace of V
for L being Linear_Compl of W
for v being Element of holds
( (v |-- W,L) `1 in W & (v |-- W,L) `2 in L )
let V be VectSp of ; for W being Subspace of V
for L being Linear_Compl of W
for v being Element of holds
( (v |-- W,L) `1 in W & (v |-- W,L) `2 in L )
let W be Subspace of V; for L being Linear_Compl of W
for v being Element of holds
( (v |-- W,L) `1 in W & (v |-- W,L) `2 in L )
let L be Linear_Compl of W; for v being Element of holds
( (v |-- W,L) `1 in W & (v |-- W,L) `2 in L )
let v be Element of ; ( (v |-- W,L) `1 in W & (v |-- W,L) `2 in L )
V is_the_direct_sum_of W,L
by Th48;
hence
( (v |-- W,L) `1 in W & (v |-- W,L) `2 in L )
by Def6; verum