Theorem r2ex 3303

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 3201	. 2 ⊢ (∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 ¬ 𝜑 ↔ ∀𝑥∀𝑦((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) → ¬ 𝜑))
2	1	r2exlem 3302	1 ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑 ↔ ∃𝑥∃𝑦((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) ∧ 𝜑))

Syntax hints:  ¬ wn 3   ↔ wb 208   ∧ wa 398  ∃wex 1780   ∈ wcel 2114  ∃wrex 3139

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 209  df-an 399  df-ex 1781  df-ral 3143  df-rex 3144

This theorem is referenced by:  rexcomOLD  3356  reeanlem  3365  elxp2  5579  elinxp  5890  rnoprab2  7258  elrnmpores  7288  oeeu  8229  omxpenlem  8618  axcnre  10586  hash2prb  13831  hashle2prv  13837  pmtrrn2  18588  fsumvma  25789  umgredg  26923  fusgr2wsp2nb  28113  spanuni  29321  5oalem7  29437  3oalem3  29441  trsp2cyc  30765  fmla0xp  32630  elfuns  33376  ellines  33613  dalem20  36844  diblsmopel  38322  iunrelexpuztr  40084  sprssspr  43663  prprelb  43698