Metamath Proof Explorer


Theorem hhssnvt

Description: Normed complex vector space property of a subspace. (Contributed by NM, 9-Apr-2008) (New usage is discouraged.)

Ref Expression
Hypothesis hhssnvt.1 W = + H × H × H norm H
Assertion hhssnvt H S W NrmCVec

Proof

Step Hyp Ref Expression
1 hhssnvt.1 W = + H × H × H norm H
2 xpeq1 H = if H S H 0 H × H = if H S H 0 × H
3 xpeq2 H = if H S H 0 if H S H 0 × H = if H S H 0 × if H S H 0
4 2 3 eqtrd H = if H S H 0 H × H = if H S H 0 × if H S H 0
5 4 reseq2d H = if H S H 0 + H × H = + if H S H 0 × if H S H 0
6 xpeq2 H = if H S H 0 × H = × if H S H 0
7 6 reseq2d H = if H S H 0 × H = × if H S H 0
8 5 7 opeq12d H = if H S H 0 + H × H × H = + if H S H 0 × if H S H 0 × if H S H 0
9 reseq2 H = if H S H 0 norm H = norm if H S H 0
10 8 9 opeq12d H = if H S H 0 + H × H × H norm H = + if H S H 0 × if H S H 0 × if H S H 0 norm if H S H 0
11 1 10 syl5eq H = if H S H 0 W = + if H S H 0 × if H S H 0 × if H S H 0 norm if H S H 0
12 11 eleq1d H = if H S H 0 W NrmCVec + if H S H 0 × if H S H 0 × if H S H 0 norm if H S H 0 NrmCVec
13 eqid + if H S H 0 × if H S H 0 × if H S H 0 norm if H S H 0 = + if H S H 0 × if H S H 0 × if H S H 0 norm if H S H 0
14 h0elsh 0 S
15 14 elimel if H S H 0 S
16 13 15 hhssnv + if H S H 0 × if H S H 0 × if H S H 0 norm if H S H 0 NrmCVec
17 12 16 dedth H S W NrmCVec