Theorem reean 3291

Description: Rearrange restricted existential quantifiers. (Contributed by NM, 27-Oct-2010.) (Proof shortened by Andrew Salmon, 30-May-2011.)

Hypotheses

Ref	Expression
reean.1	⊢ Ⅎ𝑦𝜑
reean.2	⊢ Ⅎ𝑥𝜓

Assertion

Ref	Expression
reean	⊢ (∃𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 (𝜑 ∧ 𝜓) ↔ (∃𝑥 ∈ 𝐴 𝜑 ∧ ∃𝑦 ∈ 𝐵 𝜓))

Distinct variable groups:   𝑦,𝐴   𝑥,𝐵   𝑥,𝑦

Allowed substitution hints:   𝜑(𝑥,𝑦)   𝜓(𝑥,𝑦)   𝐴(𝑥)   𝐵(𝑦)

Proof of Theorem reean

Step	Hyp	Ref	Expression
1		nfv 1918	. . . 4 ⊢ Ⅎ𝑦 𝑥 ∈ 𝐴
2		reean.1	. . . 4 ⊢ Ⅎ𝑦𝜑
3	1, 2	nfan 1903	. . 3 ⊢ Ⅎ𝑦(𝑥 ∈ 𝐴 ∧ 𝜑)
4		nfv 1918	. . . 4 ⊢ Ⅎ𝑥 𝑦 ∈ 𝐵
5		reean.2	. . . 4 ⊢ Ⅎ𝑥𝜓
6	4, 5	nfan 1903	. . 3 ⊢ Ⅎ𝑥(𝑦 ∈ 𝐵 ∧ 𝜓)
7	3, 6	eean 2348	. 2 ⊢ (∃𝑥∃𝑦((𝑥 ∈ 𝐴 ∧ 𝜑) ∧ (𝑦 ∈ 𝐵 ∧ 𝜓)) ↔ (∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑) ∧ ∃𝑦(𝑦 ∈ 𝐵 ∧ 𝜓)))
8	7	reeanlem 3290	1 ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 (𝜑 ∧ 𝜓) ↔ (∃𝑥 ∈ 𝐴 𝜑 ∧ ∃𝑦 ∈ 𝐵 𝜓))

Syntax hints:   ↔ wb 205   ∧ wa 395  Ⅎwnf 1787   ∈ wcel 2108  ∃wrex 3064

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1799  ax-4 1813  ax-5 1914  ax-6 1972  ax-7 2012  ax-10 2139  ax-11 2156  ax-12 2173

This theorem depends on definitions:  df-bi 206  df-an 396  df-or 844  df-tru 1542  df-ex 1784  df-nf 1788  df-ral 3068  df-rex 3069

This theorem is referenced by:  disjrnmpt2  42615