Theorem r2ex 3305

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 3203	. 2 ⊢ (∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 ¬ 𝜑 ↔ ∀𝑥∀𝑦((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) → ¬ 𝜑))
2	1	r2exlem 3304	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 3141

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 3145  df-rex 3146

This theorem is referenced by:  rexcomOLD  3358  reeanlem  3367  elxp2  5581  elinxp  5892  rnoprab2  7260  elrnmpores  7290  oeeu  8231  omxpenlem  8620  axcnre  10588  hash2prb  13833  hashle2prv  13839  pmtrrn2  18590  fsumvma  25791  umgredg  26925  fusgr2wsp2nb  28115  spanuni  29323  5oalem7  29439  3oalem3  29443  trsp2cyc  30767  fmla0xp  32632  elfuns  33378  ellines  33615  dalem20  36831  diblsmopel  38309  iunrelexpuztr  40071  sprssspr  43650  prprelb  43685