Metamath Proof Explorer


Theorem pjf2

Description: A projection is a function from the base set to the subspace. (Contributed by Mario Carneiro, 16-Oct-2015)

Ref Expression
Hypotheses pjf.k K = proj W
pjf.v V = Base W
Assertion pjf2 W PreHil T dom K K T : V T

Proof

Step Hyp Ref Expression
1 pjf.k K = proj W
2 pjf.v V = Base W
3 eqid + W = + W
4 eqid LSSum W = LSSum W
5 eqid 0 W = 0 W
6 eqid Cntz W = Cntz W
7 phllmod W PreHil W LMod
8 7 adantr W PreHil T dom K W LMod
9 eqid LSubSp W = LSubSp W
10 9 lsssssubg W LMod LSubSp W SubGrp W
11 8 10 syl W PreHil T dom K LSubSp W SubGrp W
12 eqid ocv W = ocv W
13 2 9 12 4 1 pjdm2 W PreHil T dom K T LSubSp W T LSSum W ocv W T = V
14 13 simprbda W PreHil T dom K T LSubSp W
15 11 14 sseldd W PreHil T dom K T SubGrp W
16 2 9 lssss T LSubSp W T V
17 14 16 syl W PreHil T dom K T V
18 2 12 9 ocvlss W PreHil T V ocv W T LSubSp W
19 17 18 syldan W PreHil T dom K ocv W T LSubSp W
20 11 19 sseldd W PreHil T dom K ocv W T SubGrp W
21 12 9 5 ocvin W PreHil T LSubSp W T ocv W T = 0 W
22 14 21 syldan W PreHil T dom K T ocv W T = 0 W
23 lmodabl W LMod W Abel
24 8 23 syl W PreHil T dom K W Abel
25 6 24 15 20 ablcntzd W PreHil T dom K T Cntz W ocv W T
26 eqid proj 1 W = proj 1 W
27 3 4 5 6 15 20 22 25 26 pj1f W PreHil T dom K T proj 1 W ocv W T : T LSSum W ocv W T T
28 12 26 1 pjval T dom K K T = T proj 1 W ocv W T
29 28 adantl W PreHil T dom K K T = T proj 1 W ocv W T
30 29 eqcomd W PreHil T dom K T proj 1 W ocv W T = K T
31 13 simplbda W PreHil T dom K T LSSum W ocv W T = V
32 30 31 feq12d W PreHil T dom K T proj 1 W ocv W T : T LSSum W ocv W T T K T : V T
33 27 32 mpbid W PreHil T dom K K T : V T