Theorem fvelima2 6935

Description: Function value in an image. (Contributed by Glauco Siliprandi, 2-Jan-2022.)

Assertion

Ref	Expression
fvelima2	⊢ ((𝐹 Fn 𝐴 ∧ 𝐵 ∈ (𝐹 “ 𝐶)) → ∃𝑥 ∈ (𝐴 ∩ 𝐶)(𝐹‘𝑥) = 𝐵)

Distinct variable groups:   𝑥,𝐴   𝑥,𝐵   𝑥,𝐶   𝑥,𝐹

Proof of Theorem fvelima2

Step	Hyp	Ref	Expression
1		elimag 6060	. . . 4 ⊢ (𝐵 ∈ (𝐹 “ 𝐶) → (𝐵 ∈ (𝐹 “ 𝐶) ↔ ∃𝑥 ∈ 𝐶 𝑥𝐹𝐵))
2	1	ibi 270	. . 3 ⊢ (𝐵 ∈ (𝐹 “ 𝐶) → ∃𝑥 ∈ 𝐶 𝑥𝐹𝐵)
3		df-rex 3088	. . 3 ⊢ (∃𝑥 ∈ 𝐶 𝑥𝐹𝐵 ↔ ∃𝑥(𝑥 ∈ 𝐶 ∧ 𝑥𝐹𝐵))
4	2, 3	sylib 221	. 2 ⊢ (𝐵 ∈ (𝐹 “ 𝐶) → ∃𝑥(𝑥 ∈ 𝐶 ∧ 𝑥𝐹𝐵))
5		fnbr 6645	. . . . . . . . 9 ⊢ ((𝐹 Fn 𝐴 ∧ 𝑥𝐹𝐵) → 𝑥 ∈ 𝐴)
6	5	adantrl 729	. . . . . . . 8 ⊢ ((𝐹 Fn 𝐴 ∧ (𝑥 ∈ 𝐶 ∧ 𝑥𝐹𝐵)) → 𝑥 ∈ 𝐴)
7		simprl 783	. . . . . . . 8 ⊢ ((𝐹 Fn 𝐴 ∧ (𝑥 ∈ 𝐶 ∧ 𝑥𝐹𝐵)) → 𝑥 ∈ 𝐶)
8	6, 7	elind 4146	. . . . . . 7 ⊢ ((𝐹 Fn 𝐴 ∧ (𝑥 ∈ 𝐶 ∧ 𝑥𝐹𝐵)) → 𝑥 ∈ (𝐴 ∩ 𝐶))
9		fnfun 6637	. . . . . . . . 9 ⊢ (𝐹 Fn 𝐴 → Fun 𝐹)
10		funbrfv 6931	. . . . . . . . . 10 ⊢ (Fun 𝐹 → (𝑥𝐹𝐵 → (𝐹‘𝑥) = 𝐵))
11	10	imp 412	. . . . . . . . 9 ⊢ ((Fun 𝐹 ∧ 𝑥𝐹𝐵) → (𝐹‘𝑥) = 𝐵)
12	9, 11	sylan 592	. . . . . . . 8 ⊢ ((𝐹 Fn 𝐴 ∧ 𝑥𝐹𝐵) → (𝐹‘𝑥) = 𝐵)
13	12	adantrl 729	. . . . . . 7 ⊢ ((𝐹 Fn 𝐴 ∧ (𝑥 ∈ 𝐶 ∧ 𝑥𝐹𝐵)) → (𝐹‘𝑥) = 𝐵)
14	8, 13	jca 521	. . . . . 6 ⊢ ((𝐹 Fn 𝐴 ∧ (𝑥 ∈ 𝐶 ∧ 𝑥𝐹𝐵)) → (𝑥 ∈ (𝐴 ∩ 𝐶) ∧ (𝐹‘𝑥) = 𝐵))
15	14	ex 418	. . . . 5 ⊢ (𝐹 Fn 𝐴 → ((𝑥 ∈ 𝐶 ∧ 𝑥𝐹𝐵) → (𝑥 ∈ (𝐴 ∩ 𝐶) ∧ (𝐹‘𝑥) = 𝐵)))
16	15	eximdv 1950	. . . 4 ⊢ (𝐹 Fn 𝐴 → (∃𝑥(𝑥 ∈ 𝐶 ∧ 𝑥𝐹𝐵) → ∃𝑥(𝑥 ∈ (𝐴 ∩ 𝐶) ∧ (𝐹‘𝑥) = 𝐵)))
17	16	imp 412	. . 3 ⊢ ((𝐹 Fn 𝐴 ∧ ∃𝑥(𝑥 ∈ 𝐶 ∧ 𝑥𝐹𝐵)) → ∃𝑥(𝑥 ∈ (𝐴 ∩ 𝐶) ∧ (𝐹‘𝑥) = 𝐵))
18		df-rex 3088	. . 3 ⊢ (∃𝑥 ∈ (𝐴 ∩ 𝐶)(𝐹‘𝑥) = 𝐵 ↔ ∃𝑥(𝑥 ∈ (𝐴 ∩ 𝐶) ∧ (𝐹‘𝑥) = 𝐵))
19	17, 18	sylibr 237	. 2 ⊢ ((𝐹 Fn 𝐴 ∧ ∃𝑥(𝑥 ∈ 𝐶 ∧ 𝑥𝐹𝐵)) → ∃𝑥 ∈ (𝐴 ∩ 𝐶)(𝐹‘𝑥) = 𝐵)
20	4, 19	sylan2 605	1 ⊢ ((𝐹 Fn 𝐴 ∧ 𝐵 ∈ (𝐹 “ 𝐶)) → ∃𝑥 ∈ (𝐴 ∩ 𝐶)(𝐹‘𝑥) = 𝐵)

This proof depends on syntax axioms:   → wi 4   ∧ wa 401   = wceq 1570  ∃wex 1812   ∈ wcel 2145  ∃wrex 3087   ∩ cin 3898   class class class wbr 5103   “ cima 5654  Fun wfun 6531   Fn wfn 6532  ‘cfv 6537

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2147  ax-9 2155  ax-10 2178  ax-12 2213  ax-ext 2733  ax-sep 5249  ax-pr 5391

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3an 1105  df-tru 1573  df-fal 1583  df-ex 1813  df-nf 1817  df-sb 2100  df-mo 2565  df-eu 2595  df-clab 2740  df-cleq 2753  df-clel 2836  df-ral 3078  df-rex 3088  df-rab 3414  df-v 3453  df-dif 3902  df-un 3904  df-in 3906  df-ss 3916  df-nul 4280  df-if 4483  df-sn 4585  df-pr 4587  df-op 4591  df-uni 4868  df-br 5104  df-opab 5168  df-id 5546  df-xp 5657  df-rel 5658  df-cnv 5659  df-co 5660  df-dm 5661  df-rn 5662  df-res 5663  df-ima 5664  df-iota 6493  df-fun 6539  df-fn 6540  df-fv 6545

This theorem is used by:  exsslsb  34222  limsupresxr  46745  liminfresxr  46746  liminfvalxr  46762