Theorem r2al 3126

Description: Double restricted universal quantification. (Contributed by NM, 19-Nov-1995.) Reduce dependencies on axioms. (Revised by Wolf Lammen, 9-Jan-2020.)

Assertion

Ref	Expression
r2al	⊢ (∀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 r2al

Step	Hyp	Ref	Expression
1		19.21v 1945	. 2 ⊢ (∀𝑦(𝑥 ∈ 𝐴 → (𝑦 ∈ 𝐵 → 𝜑)) ↔ (𝑥 ∈ 𝐴 → ∀𝑦(𝑦 ∈ 𝐵 → 𝜑)))
2	1	r2allem 3125	1 ⊢ (∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐵 𝜑 ↔ ∀𝑥∀𝑦((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵) → 𝜑))

Syntax hints:   → wi 4   ↔ wb 205   ∧ wa 395  ∀wal 1539   ∈ wcel 2109  ∀wral 3065

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1801  ax-4 1815  ax-5 1916

This theorem depends on definitions:  df-bi 206  df-an 396  df-ex 1786  df-ral 3070

This theorem is referenced by:  r3al  3127  nfra2w  3153  r2ex  3233  ralcom  3282  raliunxp  5745  codir  6022  qfto  6023  dfpo2  6196  fununi  6505  dff13  7122  mpo2eqb  7397  tz7.48lem  8256  qliftfun  8565  zorn2lem4  10239  isirred2  19924  cnmpt12  22799  cnmpt22  22806  dchrelbas3  26367  cvmlift2lem12  33255  dfso2  33701  frpoins3xpg  33766  xpord2ind  33773  inxpss  36426  inxpss3  36428  isdomn3  41009  iscnrm3lem2  46180  joindm2  46214  meetdm2  46216