Metamath Proof Explorer


Theorem mapdhval0

Description: Lemmma for ~? mapdh . (Contributed by NM, 3-Apr-2015)

Ref Expression
Hypotheses mapdh.q Q = 0 C
mapdh.i I = x V if 2 nd x = 0 ˙ Q ι h D | M N 2 nd x = J h M N 1 st 1 st x - ˙ 2 nd x = J 2 nd 1 st x R h
mapdh0.o 0 ˙ = 0 U
mapdh0.x φ X A
mapdh0.f φ F B
Assertion mapdhval0 φ I X F 0 ˙ = Q

Proof

Step Hyp Ref Expression
1 mapdh.q Q = 0 C
2 mapdh.i I = x V if 2 nd x = 0 ˙ Q ι h D | M N 2 nd x = J h M N 1 st 1 st x - ˙ 2 nd x = J 2 nd 1 st x R h
3 mapdh0.o 0 ˙ = 0 U
4 mapdh0.x φ X A
5 mapdh0.f φ F B
6 3 fvexi 0 ˙ V
7 6 a1i φ 0 ˙ V
8 1 2 4 5 7 mapdhval φ I X F 0 ˙ = if 0 ˙ = 0 ˙ Q ι h D | M N 0 ˙ = J h M N X - ˙ 0 ˙ = J F R h
9 eqid 0 ˙ = 0 ˙
10 9 iftruei if 0 ˙ = 0 ˙ Q ι h D | M N 0 ˙ = J h M N X - ˙ 0 ˙ = J F R h = Q
11 8 10 eqtrdi φ I X F 0 ˙ = Q