Theorem ralcom4 3235

Description: Commutation of restricted and unrestricted universal quantifiers. (Contributed by NM, 26-Mar-2004.) (Proof shortened by Andrew Salmon, 8-Jun-2011.) Reduce axiom dependencies. (Revised by BJ, 13-Jun-2019.)

Assertion

Ref	Expression
ralcom4	⊢ (∀𝑥 ∈ 𝐴 ∀𝑦𝜑 ↔ ∀𝑦∀𝑥 ∈ 𝐴 𝜑)

Distinct variable groups:   𝑥,𝑦   𝑦,𝐴

Allowed substitution hints:   𝜑(𝑥,𝑦)   𝐴(𝑥)

Proof of Theorem ralcom4

Step	Hyp	Ref	Expression
1		19.21v 1940	. . . . 5 ⊢ (∀𝑦(𝑥 ∈ 𝐴 → 𝜑) ↔ (𝑥 ∈ 𝐴 → ∀𝑦𝜑))
2	1	bicomi 226	. . . 4 ⊢ ((𝑥 ∈ 𝐴 → ∀𝑦𝜑) ↔ ∀𝑦(𝑥 ∈ 𝐴 → 𝜑))
3	2	albii 1820	. . 3 ⊢ (∀𝑥(𝑥 ∈ 𝐴 → ∀𝑦𝜑) ↔ ∀𝑥∀𝑦(𝑥 ∈ 𝐴 → 𝜑))
4		alcom 2163	. . 3 ⊢ (∀𝑥∀𝑦(𝑥 ∈ 𝐴 → 𝜑) ↔ ∀𝑦∀𝑥(𝑥 ∈ 𝐴 → 𝜑))
5	3, 4	bitri 277	. 2 ⊢ (∀𝑥(𝑥 ∈ 𝐴 → ∀𝑦𝜑) ↔ ∀𝑦∀𝑥(𝑥 ∈ 𝐴 → 𝜑))
6		df-ral 3143	. 2 ⊢ (∀𝑥 ∈ 𝐴 ∀𝑦𝜑 ↔ ∀𝑥(𝑥 ∈ 𝐴 → ∀𝑦𝜑))
7		df-ral 3143	. . 3 ⊢ (∀𝑥 ∈ 𝐴 𝜑 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝜑))
8	7	albii 1820	. 2 ⊢ (∀𝑦∀𝑥 ∈ 𝐴 𝜑 ↔ ∀𝑦∀𝑥(𝑥 ∈ 𝐴 → 𝜑))
9	5, 6, 8	3bitr4i 305	1 ⊢ (∀𝑥 ∈ 𝐴 ∀𝑦𝜑 ↔ ∀𝑦∀𝑥 ∈ 𝐴 𝜑)

Syntax hints:   → wi 4   ↔ wb 208  ∀wal 1535   ∈ wcel 2114  ∀wral 3138

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  ax-11 2161

This theorem depends on definitions:  df-bi 209  df-ex 1781  df-ral 3143

This theorem is referenced by:  ralxpxfr2d  3639  uniiunlem  4061  iunss  4969  disjor  5046  reliun  5689  idrefALT  5973  funimass4  6730  ralrnmpo  7289  findcard3  8761  kmlem12  9587  fimaxre3  11587  vdwmc2  16315  ramtlecl  16336  iunocv  20825  1stccn  22071  itg2leub  24335  mptelee  26681  nmoubi  28549  nmopub  29685  nmfnleub  29702  moel  30252  disjorf  30329  funcnv5mpt  30413  untuni  32935  elintfv  33007  heibor1lem  35102  ineleq  35623  inecmo  35624  pmapglbx  36920  ss2iundf  40024  ismnuprim  40650  iunssf  41372  setrec1lem2  44811