Metamath Proof Explorer


Theorem mapdhval2

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
mapdh2.x φ X A
mapdh2.f φ F B
mapdh2.y φ Y V 0 ˙
Assertion mapdhval2 φ I X F Y = ι h D | M N Y = J h M N X - ˙ Y = J F R h

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 mapdh2.x φ X A
4 mapdh2.f φ F B
5 mapdh2.y φ Y V 0 ˙
6 1 2 3 4 5 mapdhval φ I X F Y = if Y = 0 ˙ Q ι h D | M N Y = J h M N X - ˙ Y = J F R h
7 eldifsni Y V 0 ˙ Y 0 ˙
8 7 neneqd Y V 0 ˙ ¬ Y = 0 ˙
9 iffalse ¬ Y = 0 ˙ if Y = 0 ˙ Q ι h D | M N Y = J h M N X - ˙ Y = J F R h = ι h D | M N Y = J h M N X - ˙ Y = J F R h
10 5 8 9 3syl φ if Y = 0 ˙ Q ι h D | M N Y = J h M N X - ˙ Y = J F R h = ι h D | M N Y = J h M N X - ˙ Y = J F R h
11 6 10 eqtrd φ I X F Y = ι h D | M N Y = J h M N X - ˙ Y = J F R h