let K be Field; for V being VectSp of K
for W being Subspace of V
for f being nilpotent Function of V,V st f | W is Function of W,W holds
f | W is nilpotent Function of W,W
let V be VectSp of K; for W being Subspace of V
for f being nilpotent Function of V,V st f | W is Function of W,W holds
f | W is nilpotent Function of W,W
let W be Subspace of V; for f being nilpotent Function of V,V st f | W is Function of W,W holds
f | W is nilpotent Function of W,W
let f be nilpotent Function of V,V; ( f | W is Function of W,W implies f | W is nilpotent Function of W,W )
assume
f | W is Function of W,W
; f | W is nilpotent Function of W,W
then reconsider fW = f | W as Function of W,W ;
consider n being Nat such that
A1:
f |^ n = ZeroMap (V,V)
by Th13;
[#] W c= [#] V
by VECTSP_4:def 2;
then A2:
[#] W = ([#] V) /\ ([#] W)
by XBOOLE_1:28;
fW |^ n =
(ZeroMap (V,V)) | W
by A1, VECTSP11:22
.=
( the carrier of V --> (0. V)) | ([#] W)
by GRCAT_1:def 7
.=
( the carrier of V /\ ([#] W)) --> (0. V)
by FUNCOP_1:12
.=
the carrier of W --> (0. W)
by A2, VECTSP_4:11
.=
ZeroMap (W,W)
by GRCAT_1:def 7
;
hence
f | W is nilpotent Function of W,W
by Th13; verum