Metamath Proof Explorer


Theorem mapdhval0

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

Ref Expression
Hypotheses mapdh.q Q=0C
mapdh.i I=xVif2ndx=0˙QιhD|MN2ndx=JhMN1st1stx-˙2ndx=J2nd1stxRh
mapdh0.o 0˙=0U
mapdh0.x φXA
mapdh0.f φFB
Assertion mapdhval0 φIXF0˙=Q

Proof

Step Hyp Ref Expression
1 mapdh.q Q=0C
2 mapdh.i I=xVif2ndx=0˙QιhD|MN2ndx=JhMN1st1stx-˙2ndx=J2nd1stxRh
3 mapdh0.o 0˙=0U
4 mapdh0.x φXA
5 mapdh0.f φFB
6 3 fvexi 0˙V
7 6 a1i φ0˙V
8 1 2 4 5 7 mapdhval φIXF0˙=if0˙=0˙QιhD|MN0˙=JhMNX-˙0˙=JFRh
9 eqid 0˙=0˙
10 9 iftruei if0˙=0˙QιhD|MN0˙=JhMNX-˙0˙=JFRh=Q
11 8 10 eqtrdi φIXF0˙=Q