Theorem nrmo 35889

Description: "At most one" restricted existential quantifier for a statement which is never true. (Contributed by Thierry Arnoux, 27-Nov-2023.)

Hypothesis

Ref	Expression
nrmo.1	⊢ (𝑥 ∈ 𝐴 → ¬ 𝜑)

Assertion

Ref	Expression
nrmo	⊢ ∃*𝑥 ∈ 𝐴 𝜑

Proof of Theorem nrmo

Step	Hyp	Ref	Expression
1		mofal 35888	. . 3 ⊢ ∃*𝑥⊥
2		nrmo.1	. . . . . . 7 ⊢ (𝑥 ∈ 𝐴 → ¬ 𝜑)
3	2	imori 853	. . . . . 6 ⊢ (¬ 𝑥 ∈ 𝐴 ∨ ¬ 𝜑)
4		ianor 980	. . . . . 6 ⊢ (¬ (𝑥 ∈ 𝐴 ∧ 𝜑) ↔ (¬ 𝑥 ∈ 𝐴 ∨ ¬ 𝜑))
5	3, 4	mpbir 230	. . . . 5 ⊢ ¬ (𝑥 ∈ 𝐴 ∧ 𝜑)
6	5	bifal 1550	. . . 4 ⊢ ((𝑥 ∈ 𝐴 ∧ 𝜑) ↔ ⊥)
7	6	mobii 2538	. . 3 ⊢ (∃*𝑥(𝑥 ∈ 𝐴 ∧ 𝜑) ↔ ∃*𝑥⊥)
8	1, 7	mpbir 230	. 2 ⊢ ∃*𝑥(𝑥 ∈ 𝐴 ∧ 𝜑)
9		df-rmo 3372	. 2 ⊢ (∃*𝑥 ∈ 𝐴 𝜑 ↔ ∃*𝑥(𝑥 ∈ 𝐴 ∧ 𝜑))
10	8, 9	mpbir 230	1 ⊢ ∃*𝑥 ∈ 𝐴 𝜑

Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 395   ∨ wo 846  ⊥wfal 1546   ∈ wcel 2099  ∃*wmo 2528  ∃*wrmo 3371

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1790  ax-4 1804  ax-5 1906  ax-6 1964

This theorem depends on definitions:  df-bi 206  df-an 396  df-or 847  df-tru 1537  df-fal 1547  df-ex 1775  df-mo 2530  df-rmo 3372

This theorem is referenced by: (None)