Theorem rexdifi 4089

Description: Restricted existential quantification over a difference. (Contributed by AV, 25-Oct-2023.)

Assertion

Ref	Expression
rexdifi	⊢ ((∃𝑥 ∈ 𝐴 𝜑 ∧ ∀𝑥 ∈ 𝐵 ¬ 𝜑) → ∃𝑥 ∈ (𝐴 ∖ 𝐵)𝜑)

Proof of Theorem rexdifi

Step	Hyp	Ref	Expression
1		df-rex 3091	. . 3 ⊢ (∃𝑥 ∈ 𝐴 𝜑 ↔ ∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑))
2		df-ral 3081	. . 3 ⊢ (∀𝑥 ∈ 𝐵 ¬ 𝜑 ↔ ∀𝑥(𝑥 ∈ 𝐵 → ¬ 𝜑))
3		nfa1 2191	. . . . 5 ⊢ Ⅎ𝑥∀𝑥(𝑥 ∈ 𝐵 → ¬ 𝜑)
4		simprl 783	. . . . . . . 8 ⊢ ((∀𝑥(𝑥 ∈ 𝐵 → ¬ 𝜑) ∧ (𝑥 ∈ 𝐴 ∧ 𝜑)) → 𝑥 ∈ 𝐴)
5		con2 136	. . . . . . . . . . . 12 ⊢ ((𝑥 ∈ 𝐵 → ¬ 𝜑) → (𝜑 → ¬ 𝑥 ∈ 𝐵))
6	5	sps 2225	. . . . . . . . . . 11 ⊢ (∀𝑥(𝑥 ∈ 𝐵 → ¬ 𝜑) → (𝜑 → ¬ 𝑥 ∈ 𝐵))
7	6	com12 33	. . . . . . . . . 10 ⊢ (𝜑 → (∀𝑥(𝑥 ∈ 𝐵 → ¬ 𝜑) → ¬ 𝑥 ∈ 𝐵))
8	7	adantl 487	. . . . . . . . 9 ⊢ ((𝑥 ∈ 𝐴 ∧ 𝜑) → (∀𝑥(𝑥 ∈ 𝐵 → ¬ 𝜑) → ¬ 𝑥 ∈ 𝐵))
9	8	impcom 413	. . . . . . . 8 ⊢ ((∀𝑥(𝑥 ∈ 𝐵 → ¬ 𝜑) ∧ (𝑥 ∈ 𝐴 ∧ 𝜑)) → ¬ 𝑥 ∈ 𝐵)
10	4, 9	eldifd 4053	. . . . . . 7 ⊢ ((∀𝑥(𝑥 ∈ 𝐵 → ¬ 𝜑) ∧ (𝑥 ∈ 𝐴 ∧ 𝜑)) → 𝑥 ∈ (𝐴 ∖ 𝐵))
11		simprr 785	. . . . . . 7 ⊢ ((∀𝑥(𝑥 ∈ 𝐵 → ¬ 𝜑) ∧ (𝑥 ∈ 𝐴 ∧ 𝜑)) → 𝜑)
12	10, 11	jca 521	. . . . . 6 ⊢ ((∀𝑥(𝑥 ∈ 𝐵 → ¬ 𝜑) ∧ (𝑥 ∈ 𝐴 ∧ 𝜑)) → (𝑥 ∈ (𝐴 ∖ 𝐵) ∧ 𝜑))
13	12	ex 418	. . . . 5 ⊢ (∀𝑥(𝑥 ∈ 𝐵 → ¬ 𝜑) → ((𝑥 ∈ 𝐴 ∧ 𝜑) → (𝑥 ∈ (𝐴 ∖ 𝐵) ∧ 𝜑)))
14	3, 13	eximd 2256	. . . 4 ⊢ (∀𝑥(𝑥 ∈ 𝐵 → ¬ 𝜑) → (∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑) → ∃𝑥(𝑥 ∈ (𝐴 ∖ 𝐵) ∧ 𝜑)))
15	14	impcom 413	. . 3 ⊢ ((∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑) ∧ ∀𝑥(𝑥 ∈ 𝐵 → ¬ 𝜑)) → ∃𝑥(𝑥 ∈ (𝐴 ∖ 𝐵) ∧ 𝜑))
16	1, 2, 15	syl2anb 610	. 2 ⊢ ((∃𝑥 ∈ 𝐴 𝜑 ∧ ∀𝑥 ∈ 𝐵 ¬ 𝜑) → ∃𝑥(𝑥 ∈ (𝐴 ∖ 𝐵) ∧ 𝜑))
17		df-rex 3091	. 2 ⊢ (∃𝑥 ∈ (𝐴 ∖ 𝐵)𝜑 ↔ ∃𝑥(𝑥 ∈ (𝐴 ∖ 𝐵) ∧ 𝜑))
18	16, 17	sylibr 237	1 ⊢ ((∃𝑥 ∈ 𝐴 𝜑 ∧ ∀𝑥 ∈ 𝐵 ¬ 𝜑) → ∃𝑥 ∈ (𝐴 ∖ 𝐵)𝜑)

This proof depends on syntax axioms:  ¬ wn 3   → wi 4   ∧ wa 401  ∀wal 1568  ∃wex 1812   ∈ wcel 2147  ∀wral 3080  ∃wrex 3090   ∖ cdif 4048

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 1945  ax-6 2002  ax-7 2043  ax-8 2149  ax-9 2157  ax-10 2180  ax-12 2216  ax-ext 2735

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-tru 1573  df-ex 1813  df-nf 1817  df-sb 2102  df-clab 2742  df-cleq 2755  df-clel 2839  df-ral 3081  df-rex 3091  df-v 3456  df-dif 4050

This theorem is used by:  releldmdifi  8091