Theorem r2ex 3177

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 3176	. 2 ⊢ (∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 ¬ 𝜑 ↔ ∀𝑥∀𝑦((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) → ¬ 𝜑))
2	1	r2exlem 3129	1 ⊢ (∃𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑 ↔ ∃𝑥∃𝑦((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) ∧ 𝜑))

Syntax hints:  ¬ wn 3   ↔ wb 207   ∧ wa 396  ∃wex 1786   ∈ wcel 2119  ∃wrex 3064

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1802  ax-4 1816  ax-5 1917

This theorem depends on definitions:  df-bi 208  df-an 397  df-ex 1787  df-ral 3055  df-rex 3065

This theorem is referenced by:  r3ex  3179  reeanlem  3211  elxp2  5649  elinxp  5978  rnoprab2  7469  elrnmpores  7501  oeeu  8536  omxpenlem  9013  axcnre  11085  hash2prb  14432  hashle2prv  14438  pmtrrn2  19433  fsumvma  27201  umgredg  29232  fusgr2wsp2nb  30429  spanuni  31640  5oalem7  31756  3oalem3  31760  trsp2cyc  33211  fmla0xp  35618  elfuns  36148  ellines  36387  dalem20  40192  diblsmopel  41670  iunrelexpuztr  44170  sprssspr  47963  prprelb  47998