Theorem nrmo 36980

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 36979	. . 3 ⊢ ∃*𝑥⊥
2		nrmo.1	. . . . . . 7 ⊢ (𝑥 ∈ 𝐴 → ¬ 𝜑)
3	2	imori 868	. . . . . 6 ⊢ (¬ 𝑥 ∈ 𝐴 ∨ ¬ 𝜑)
4		ianor 997	. . . . . 6 ⊢ (¬ (𝑥 ∈ 𝐴 ∧ 𝜑) ↔ (¬ 𝑥 ∈ 𝐴 ∨ ¬ 𝜑))
5	3, 4	mpbir 234	. . . . 5 ⊢ ¬ (𝑥 ∈ 𝐴 ∧ 𝜑)
6	5	bifal 1586	. . . 4 ⊢ ((𝑥 ∈ 𝐴 ∧ 𝜑) ↔ ⊥)
7	6	mobii 2578	. . 3 ⊢ (∃*𝑥(𝑥 ∈ 𝐴 ∧ 𝜑) ↔ ∃*𝑥⊥)
8	1, 7	mpbir 234	. 2 ⊢ ∃*𝑥(𝑥 ∈ 𝐴 ∧ 𝜑)
9		df-rmo 3371	. 2 ⊢ (∃*𝑥 ∈ 𝐴 𝜑 ↔ ∃*𝑥(𝑥 ∈ 𝐴 ∧ 𝜑))
10	8, 9	mpbir 234	1 ⊢ ∃*𝑥 ∈ 𝐴 𝜑

This proof depends on syntax axioms:  ¬ wn 3   → wi 4   ∧ wa 401   ∨ wo 861  ⊥wfal 1582   ∈ wcel 2146  ∃*wmo 2567  ∃*wrmo 3370

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

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-tru 1573  df-fal 1583  df-ex 1813  df-mo 2569  df-rmo 3371

This theorem is used by: (None)