Metamath Proof Explorer


Theorem iinpreima

Description: Preimage of an intersection. (Contributed by FL, 16-Apr-2012)

Ref Expression
Assertion iinpreima ( ( Fun 𝐹𝐴 ≠ ∅ ) → ( 𝐹 𝑥𝐴 𝐵 ) = 𝑥𝐴 ( 𝐹𝐵 ) )

Proof

Step Hyp Ref Expression
1 simpll ( ( ( Fun 𝐹𝐴 ≠ ∅ ) ∧ 𝑦 ∈ ( 𝐹 𝑥𝐴 𝐵 ) ) → Fun 𝐹 )
2 cnvimass ( 𝐹 𝑥𝐴 𝐵 ) ⊆ dom 𝐹
3 2 sseli ( 𝑦 ∈ ( 𝐹 𝑥𝐴 𝐵 ) → 𝑦 ∈ dom 𝐹 )
4 3 adantl ( ( ( Fun 𝐹𝐴 ≠ ∅ ) ∧ 𝑦 ∈ ( 𝐹 𝑥𝐴 𝐵 ) ) → 𝑦 ∈ dom 𝐹 )
5 fvex ( 𝐹𝑦 ) ∈ V
6 fvimacnvi ( ( Fun 𝐹𝑦 ∈ ( 𝐹 𝑥𝐴 𝐵 ) ) → ( 𝐹𝑦 ) ∈ 𝑥𝐴 𝐵 )
7 6 adantlr ( ( ( Fun 𝐹𝐴 ≠ ∅ ) ∧ 𝑦 ∈ ( 𝐹 𝑥𝐴 𝐵 ) ) → ( 𝐹𝑦 ) ∈ 𝑥𝐴 𝐵 )
8 eliin ( ( 𝐹𝑦 ) ∈ V → ( ( 𝐹𝑦 ) ∈ 𝑥𝐴 𝐵 ↔ ∀ 𝑥𝐴 ( 𝐹𝑦 ) ∈ 𝐵 ) )
9 8 biimpa ( ( ( 𝐹𝑦 ) ∈ V ∧ ( 𝐹𝑦 ) ∈ 𝑥𝐴 𝐵 ) → ∀ 𝑥𝐴 ( 𝐹𝑦 ) ∈ 𝐵 )
10 5 7 9 sylancr ( ( ( Fun 𝐹𝐴 ≠ ∅ ) ∧ 𝑦 ∈ ( 𝐹 𝑥𝐴 𝐵 ) ) → ∀ 𝑥𝐴 ( 𝐹𝑦 ) ∈ 𝐵 )
11 fvimacnv ( ( Fun 𝐹𝑦 ∈ dom 𝐹 ) → ( ( 𝐹𝑦 ) ∈ 𝐵𝑦 ∈ ( 𝐹𝐵 ) ) )
12 11 ralbidv ( ( Fun 𝐹𝑦 ∈ dom 𝐹 ) → ( ∀ 𝑥𝐴 ( 𝐹𝑦 ) ∈ 𝐵 ↔ ∀ 𝑥𝐴 𝑦 ∈ ( 𝐹𝐵 ) ) )
13 12 biimpa ( ( ( Fun 𝐹𝑦 ∈ dom 𝐹 ) ∧ ∀ 𝑥𝐴 ( 𝐹𝑦 ) ∈ 𝐵 ) → ∀ 𝑥𝐴 𝑦 ∈ ( 𝐹𝐵 ) )
14 1 4 10 13 syl21anc ( ( ( Fun 𝐹𝐴 ≠ ∅ ) ∧ 𝑦 ∈ ( 𝐹 𝑥𝐴 𝐵 ) ) → ∀ 𝑥𝐴 𝑦 ∈ ( 𝐹𝐵 ) )
15 eliin ( 𝑦 ∈ V → ( 𝑦 𝑥𝐴 ( 𝐹𝐵 ) ↔ ∀ 𝑥𝐴 𝑦 ∈ ( 𝐹𝐵 ) ) )
16 15 elv ( 𝑦 𝑥𝐴 ( 𝐹𝐵 ) ↔ ∀ 𝑥𝐴 𝑦 ∈ ( 𝐹𝐵 ) )
17 14 16 sylibr ( ( ( Fun 𝐹𝐴 ≠ ∅ ) ∧ 𝑦 ∈ ( 𝐹 𝑥𝐴 𝐵 ) ) → 𝑦 𝑥𝐴 ( 𝐹𝐵 ) )
18 simpll ( ( ( Fun 𝐹𝐴 ≠ ∅ ) ∧ 𝑦 𝑥𝐴 ( 𝐹𝐵 ) ) → Fun 𝐹 )
19 15 biimpd ( 𝑦 ∈ V → ( 𝑦 𝑥𝐴 ( 𝐹𝐵 ) → ∀ 𝑥𝐴 𝑦 ∈ ( 𝐹𝐵 ) ) )
20 19 elv ( 𝑦 𝑥𝐴 ( 𝐹𝐵 ) → ∀ 𝑥𝐴 𝑦 ∈ ( 𝐹𝐵 ) )
21 20 adantl ( ( ( Fun 𝐹𝐴 ≠ ∅ ) ∧ 𝑦 𝑥𝐴 ( 𝐹𝐵 ) ) → ∀ 𝑥𝐴 𝑦 ∈ ( 𝐹𝐵 ) )
22 fvimacnvi ( ( Fun 𝐹𝑦 ∈ ( 𝐹𝐵 ) ) → ( 𝐹𝑦 ) ∈ 𝐵 )
23 22 ex ( Fun 𝐹 → ( 𝑦 ∈ ( 𝐹𝐵 ) → ( 𝐹𝑦 ) ∈ 𝐵 ) )
24 23 ralimdv ( Fun 𝐹 → ( ∀ 𝑥𝐴 𝑦 ∈ ( 𝐹𝐵 ) → ∀ 𝑥𝐴 ( 𝐹𝑦 ) ∈ 𝐵 ) )
25 18 21 24 sylc ( ( ( Fun 𝐹𝐴 ≠ ∅ ) ∧ 𝑦 𝑥𝐴 ( 𝐹𝐵 ) ) → ∀ 𝑥𝐴 ( 𝐹𝑦 ) ∈ 𝐵 )
26 5 8 ax-mp ( ( 𝐹𝑦 ) ∈ 𝑥𝐴 𝐵 ↔ ∀ 𝑥𝐴 ( 𝐹𝑦 ) ∈ 𝐵 )
27 25 26 sylibr ( ( ( Fun 𝐹𝐴 ≠ ∅ ) ∧ 𝑦 𝑥𝐴 ( 𝐹𝐵 ) ) → ( 𝐹𝑦 ) ∈ 𝑥𝐴 𝐵 )
28 r19.2zb ( 𝐴 ≠ ∅ ↔ ( ∀ 𝑥𝐴 𝑦 ∈ ( 𝐹𝐵 ) → ∃ 𝑥𝐴 𝑦 ∈ ( 𝐹𝐵 ) ) )
29 28 biimpi ( 𝐴 ≠ ∅ → ( ∀ 𝑥𝐴 𝑦 ∈ ( 𝐹𝐵 ) → ∃ 𝑥𝐴 𝑦 ∈ ( 𝐹𝐵 ) ) )
30 cnvimass ( 𝐹𝐵 ) ⊆ dom 𝐹
31 30 sseli ( 𝑦 ∈ ( 𝐹𝐵 ) → 𝑦 ∈ dom 𝐹 )
32 31 rexlimivw ( ∃ 𝑥𝐴 𝑦 ∈ ( 𝐹𝐵 ) → 𝑦 ∈ dom 𝐹 )
33 29 32 syl6 ( 𝐴 ≠ ∅ → ( ∀ 𝑥𝐴 𝑦 ∈ ( 𝐹𝐵 ) → 𝑦 ∈ dom 𝐹 ) )
34 16 33 syl5bi ( 𝐴 ≠ ∅ → ( 𝑦 𝑥𝐴 ( 𝐹𝐵 ) → 𝑦 ∈ dom 𝐹 ) )
35 34 adantl ( ( Fun 𝐹𝐴 ≠ ∅ ) → ( 𝑦 𝑥𝐴 ( 𝐹𝐵 ) → 𝑦 ∈ dom 𝐹 ) )
36 35 imp ( ( ( Fun 𝐹𝐴 ≠ ∅ ) ∧ 𝑦 𝑥𝐴 ( 𝐹𝐵 ) ) → 𝑦 ∈ dom 𝐹 )
37 fvimacnv ( ( Fun 𝐹𝑦 ∈ dom 𝐹 ) → ( ( 𝐹𝑦 ) ∈ 𝑥𝐴 𝐵𝑦 ∈ ( 𝐹 𝑥𝐴 𝐵 ) ) )
38 18 36 37 syl2anc ( ( ( Fun 𝐹𝐴 ≠ ∅ ) ∧ 𝑦 𝑥𝐴 ( 𝐹𝐵 ) ) → ( ( 𝐹𝑦 ) ∈ 𝑥𝐴 𝐵𝑦 ∈ ( 𝐹 𝑥𝐴 𝐵 ) ) )
39 27 38 mpbid ( ( ( Fun 𝐹𝐴 ≠ ∅ ) ∧ 𝑦 𝑥𝐴 ( 𝐹𝐵 ) ) → 𝑦 ∈ ( 𝐹 𝑥𝐴 𝐵 ) )
40 17 39 impbida ( ( Fun 𝐹𝐴 ≠ ∅ ) → ( 𝑦 ∈ ( 𝐹 𝑥𝐴 𝐵 ) ↔ 𝑦 𝑥𝐴 ( 𝐹𝐵 ) ) )
41 40 eqrdv ( ( Fun 𝐹𝐴 ≠ ∅ ) → ( 𝐹 𝑥𝐴 𝐵 ) = 𝑥𝐴 ( 𝐹𝐵 ) )