Theorem ralcom4OLD 3274

Description: Obsolete version of ralcom4 3273 as of 31-Oct-2024. (Contributed by NM, 26-Mar-2004.) (Proof shortened by Andrew Salmon, 8-Jun-2011.) Reduce axiom dependencies. (Revised by BJ, 13-Jun-2019.) (New usage is discouraged.) (Proof modification is discouraged.)

Assertion

Ref	Expression
ralcom4OLD	⊢ (∀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 ralcom4OLD

Step	Hyp	Ref	Expression
1		19.21v 1934	. . . . 5 ⊢ (∀𝑦(𝑥 ∈ 𝐴 → 𝜑) ↔ (𝑥 ∈ 𝐴 → ∀𝑦𝜑))
2	1	bicomi 223	. . . 4 ⊢ ((𝑥 ∈ 𝐴 → ∀𝑦𝜑) ↔ ∀𝑦(𝑥 ∈ 𝐴 → 𝜑))
3	2	albii 1813	. . 3 ⊢ (∀𝑥(𝑥 ∈ 𝐴 → ∀𝑦𝜑) ↔ ∀𝑥∀𝑦(𝑥 ∈ 𝐴 → 𝜑))
4		alcom 2148	. . 3 ⊢ (∀𝑥∀𝑦(𝑥 ∈ 𝐴 → 𝜑) ↔ ∀𝑦∀𝑥(𝑥 ∈ 𝐴 → 𝜑))
5	3, 4	bitri 274	. 2 ⊢ (∀𝑥(𝑥 ∈ 𝐴 → ∀𝑦𝜑) ↔ ∀𝑦∀𝑥(𝑥 ∈ 𝐴 → 𝜑))
6		df-ral 3051	. 2 ⊢ (∀𝑥 ∈ 𝐴 ∀𝑦𝜑 ↔ ∀𝑥(𝑥 ∈ 𝐴 → ∀𝑦𝜑))
7		df-ral 3051	. . 3 ⊢ (∀𝑥 ∈ 𝐴 𝜑 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝜑))
8	7	albii 1813	. 2 ⊢ (∀𝑦∀𝑥 ∈ 𝐴 𝜑 ↔ ∀𝑦∀𝑥(𝑥 ∈ 𝐴 → 𝜑))
9	5, 6, 8	3bitr4i 302	1 ⊢ (∀𝑥 ∈ 𝐴 ∀𝑦𝜑 ↔ ∀𝑦∀𝑥 ∈ 𝐴 𝜑)

Syntax hints:   → wi 4   ↔ wb 205  ∀wal 1531   ∈ wcel 2098  ∀wral 3050

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1789  ax-4 1803  ax-5 1905  ax-11 2146

This theorem depends on definitions:  df-bi 206  df-ex 1774  df-ral 3051

This theorem is referenced by: (None)