Metamath Proof Explorer


Theorem frege116

Description: One direction of dffrege115 . Proposition 116 of Frege1879 p. 77. (Contributed by RP, 8-Jul-2020) (Proof modification is discouraged.)

Ref Expression
Hypothesis frege116.x X U
Assertion frege116 Fun R -1 -1 b b R X a b R a a = X

Proof

Step Hyp Ref Expression
1 frege116.x X U
2 dffrege115 c b b R c a b R a a = c Fun R -1 -1
3 1 frege68c c b b R c a b R a a = c Fun R -1 -1 Fun R -1 -1 [˙X / c]˙ b b R c a b R a a = c
4 sbcal [˙X / c]˙ b b R c a b R a a = c b [˙X / c]˙ b R c a b R a a = c
5 sbcimg X U [˙X / c]˙ b R c a b R a a = c [˙X / c]˙ b R c [˙X / c]˙ a b R a a = c
6 1 5 ax-mp [˙X / c]˙ b R c a b R a a = c [˙X / c]˙ b R c [˙X / c]˙ a b R a a = c
7 sbcbr2g X U [˙X / c]˙ b R c b R X / c c
8 1 7 ax-mp [˙X / c]˙ b R c b R X / c c
9 csbvarg X U X / c c = X
10 1 9 ax-mp X / c c = X
11 10 breq2i b R X / c c b R X
12 8 11 bitri [˙X / c]˙ b R c b R X
13 sbcal [˙X / c]˙ a b R a a = c a [˙X / c]˙ b R a a = c
14 sbcimg X U [˙X / c]˙ b R a a = c [˙X / c]˙ b R a [˙X / c]˙ a = c
15 1 14 ax-mp [˙X / c]˙ b R a a = c [˙X / c]˙ b R a [˙X / c]˙ a = c
16 sbcg X U [˙X / c]˙ b R a b R a
17 1 16 ax-mp [˙X / c]˙ b R a b R a
18 sbceq2g X U [˙X / c]˙ a = c a = X / c c
19 1 18 ax-mp [˙X / c]˙ a = c a = X / c c
20 10 eqeq2i a = X / c c a = X
21 19 20 bitri [˙X / c]˙ a = c a = X
22 17 21 imbi12i [˙X / c]˙ b R a [˙X / c]˙ a = c b R a a = X
23 15 22 bitri [˙X / c]˙ b R a a = c b R a a = X
24 23 albii a [˙X / c]˙ b R a a = c a b R a a = X
25 13 24 bitri [˙X / c]˙ a b R a a = c a b R a a = X
26 12 25 imbi12i [˙X / c]˙ b R c [˙X / c]˙ a b R a a = c b R X a b R a a = X
27 6 26 bitri [˙X / c]˙ b R c a b R a a = c b R X a b R a a = X
28 27 albii b [˙X / c]˙ b R c a b R a a = c b b R X a b R a a = X
29 4 28 bitri [˙X / c]˙ b b R c a b R a a = c b b R X a b R a a = X
30 3 29 syl6ib c b b R c a b R a a = c Fun R -1 -1 Fun R -1 -1 b b R X a b R a a = X
31 2 30 ax-mp Fun R -1 -1 b b R X a b R a a = X