Theorem r2ex 3169

Description: Double restricted existential quantification. (Contributed by NM, 11-Nov-1995.) Reduce dependencies on axioms. (Revised by Wolf Lammen, 10-Jan-2020.)

Assertion

Ref	Expression
r2ex	⊢ (∃𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑 ↔ ∃𝑥∃𝑦((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) ∧ 𝜑))

Distinct variable groups:   𝑥,𝑦   𝑦,𝐴

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

Proof of Theorem r2ex

Step	Hyp	Ref	Expression
1		r2al 3168	. 2 ⊢ (∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 ¬ 𝜑 ↔ ∀𝑥∀𝑦((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) → ¬ 𝜑))
2	1	r2exlem 3121	1 ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑 ↔ ∃𝑥∃𝑦((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) ∧ 𝜑))

Syntax hints:  ¬ wn 3   ↔ wb 206   ∧ wa 395  ∃wex 1780   ∈ wcel 2111  ∃wrex 3056

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1796  ax-4 1810  ax-5 1911

This theorem depends on definitions:  df-bi 207  df-an 396  df-ex 1781  df-ral 3048  df-rex 3057

This theorem is referenced by:  r3ex  3171  reeanlem  3203  elxp2  5640  elinxp  5968  rnoprab2  7452  elrnmpores  7484  oeeu  8518  omxpenlem  8991  axcnre  11052  hash2prb  14376  hashle2prv  14382  pmtrrn2  19370  fsumvma  27149  umgredg  29114  fusgr2wsp2nb  30309  spanuni  31519  5oalem7  31635  3oalem3  31639  trsp2cyc  33087  fmla0xp  35415  elfuns  35948  ellines  36185  dalem20  39731  diblsmopel  41209  iunrelexpuztr  43751  sprssspr  47511  prprelb  47546