Theorem r2ex 3175

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 3174	. 2 ⊢ (∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 ¬ 𝜑 ↔ ∀𝑥∀𝑦((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) → ¬ 𝜑))
2	1	r2exlem 3127	1 ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑 ↔ ∃𝑥∃𝑦((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) ∧ 𝜑))

Syntax hints:  ¬ wn 3   ↔ wb 206   ∧ wa 395  ∃wex 1781   ∈ wcel 2114  ∃wrex 3062

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1912

This theorem depends on definitions:  df-bi 207  df-an 396  df-ex 1782  df-ral 3053  df-rex 3063

This theorem is referenced by:  r3ex  3177  reeanlem  3209  elxp2  5648  elinxp  5978  rnoprab2  7466  elrnmpores  7498  oeeu  8532  omxpenlem  9009  axcnre  11078  hash2prb  14425  hashle2prv  14431  pmtrrn2  19426  fsumvma  27190  umgredg  29221  fusgr2wsp2nb  30419  spanuni  31630  5oalem7  31746  3oalem3  31750  trsp2cyc  33199  fmla0xp  35581  elfuns  36111  ellines  36350  dalem20  40153  diblsmopel  41631  iunrelexpuztr  44164  sprssspr  47953  prprelb  47988