Theorem euan 2518

Description: Introduction of a conjunct into uniqueness quantifier. (Contributed by NM, 19-Feb-2005.) (Proof shortened by Andrew Salmon, 9-Jul-2011.) (Proof shortened by Wolf Lammen, 24-Dec-2018.)

Hypothesis

Ref	Expression
moanim.1	⊢ Ⅎ𝑥𝜑

Assertion

Ref	Expression
euan	⊢ (∃!𝑥(𝜑 ∧ 𝜓) ↔ (𝜑 ∧ ∃!𝑥𝜓))

Proof of Theorem euan

Step	Hyp	Ref	Expression
1		euex 2482	. . . 4 ⊢ (∃!𝑥(𝜑 ∧ 𝜓) → ∃𝑥(𝜑 ∧ 𝜓))
2		moanim.1	. . . . 5 ⊢ Ⅎ𝑥𝜑
3		simpl 472	. . . . 5 ⊢ ((𝜑 ∧ 𝜓) → 𝜑)
4	2, 3	exlimi 2073	. . . 4 ⊢ (∃𝑥(𝜑 ∧ 𝜓) → 𝜑)
5	1, 4	syl 17	. . 3 ⊢ (∃!𝑥(𝜑 ∧ 𝜓) → 𝜑)
6		ibar 524	. . . . 5 ⊢ (𝜑 → (𝜓 ↔ (𝜑 ∧ 𝜓)))
7	2, 6	eubid 2476	. . . 4 ⊢ (𝜑 → (∃!𝑥𝜓 ↔ ∃!𝑥(𝜑 ∧ 𝜓)))
8	7	biimprcd 239	. . 3 ⊢ (∃!𝑥(𝜑 ∧ 𝜓) → (𝜑 → ∃!𝑥𝜓))
9	5, 8	jcai 557	. 2 ⊢ (∃!𝑥(𝜑 ∧ 𝜓) → (𝜑 ∧ ∃!𝑥𝜓))
10	7	biimpa 500	. 2 ⊢ ((𝜑 ∧ ∃!𝑥𝜓) → ∃!𝑥(𝜑 ∧ 𝜓))
11	9, 10	impbii 198	1 ⊢ (∃!𝑥(𝜑 ∧ 𝜓) ↔ (𝜑 ∧ ∃!𝑥𝜓))

Syntax hints:   ↔ wb 195   ∧ wa 383  ∃wex 1695  Ⅎwnf 1699  ∃!weu 2458

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1713  ax-4 1728  ax-5 1827  ax-6 1875  ax-7 1922  ax-12 2034

This theorem depends on definitions:  df-bi 196  df-or 384  df-an 385  df-ex 1696  df-nf 1701  df-eu 2462

This theorem is referenced by:  euanv  2522  2eu7  2547  2eu8  2548