Metamath Proof Explorer


Theorem djhval

Description: Subspace join for DVecH vector space. (Contributed by NM, 19-Jul-2014)

Ref Expression
Hypotheses djhval.h H=LHypK
djhval.u U=DVecHKW
djhval.v V=BaseU
djhval.o ˙=ocHKW
djhval.j ˙=joinHKW
Assertion djhval KHLWHXVYVX˙Y=˙˙X˙Y

Proof

Step Hyp Ref Expression
1 djhval.h H=LHypK
2 djhval.u U=DVecHKW
3 djhval.v V=BaseU
4 djhval.o ˙=ocHKW
5 djhval.j ˙=joinHKW
6 1 2 3 4 5 djhfval KHLWH˙=x𝒫V,y𝒫V˙˙x˙y
7 6 adantr KHLWHXVYV˙=x𝒫V,y𝒫V˙˙x˙y
8 7 oveqd KHLWHXVYVX˙Y=Xx𝒫V,y𝒫V˙˙x˙yY
9 3 fvexi VV
10 9 elpw2 X𝒫VXV
11 10 biimpri XVX𝒫V
12 11 ad2antrl KHLWHXVYVX𝒫V
13 9 elpw2 Y𝒫VYV
14 13 biimpri YVY𝒫V
15 14 ad2antll KHLWHXVYVY𝒫V
16 fvexd KHLWHXVYV˙˙X˙YV
17 fveq2 x=X˙x=˙X
18 17 ineq1d x=X˙x˙y=˙X˙y
19 18 fveq2d x=X˙˙x˙y=˙˙X˙y
20 fveq2 y=Y˙y=˙Y
21 20 ineq2d y=Y˙X˙y=˙X˙Y
22 21 fveq2d y=Y˙˙X˙y=˙˙X˙Y
23 eqid x𝒫V,y𝒫V˙˙x˙y=x𝒫V,y𝒫V˙˙x˙y
24 19 22 23 ovmpog X𝒫VY𝒫V˙˙X˙YVXx𝒫V,y𝒫V˙˙x˙yY=˙˙X˙Y
25 12 15 16 24 syl3anc KHLWHXVYVXx𝒫V,y𝒫V˙˙x˙yY=˙˙X˙Y
26 8 25 eqtrd KHLWHXVYVX˙Y=˙˙X˙Y