Theorem bj-ralcom4 32062

Description: Remove from ralcom4 3197 dependency on ax-ext 2590 and ax-13 2234 (and on df-or 384, df-an 385, df-tru 1478, df-sb 1868, df-clab 2597, df-cleq 2603, df-clel 2606, df-nfc 2740, df-v 3175). This proof uses only df-ral 2901 on top of first-order logic. (Contributed by BJ, 13-Jun-2019.) (Proof modification is discouraged.)

Assertion

Ref	Expression
bj-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 bj-ralcom4

Step	Hyp	Ref	Expression
1		19.21v 1855	. . . . 5 ⊢ (∀𝑦(𝑥 ∈ 𝐴 → 𝜑) ↔ (𝑥 ∈ 𝐴 → ∀𝑦𝜑))
2	1	bicomi 213	. . . 4 ⊢ ((𝑥 ∈ 𝐴 → ∀𝑦𝜑) ↔ ∀𝑦(𝑥 ∈ 𝐴 → 𝜑))
3	2	albii 1737	. . 3 ⊢ (∀𝑥(𝑥 ∈ 𝐴 → ∀𝑦𝜑) ↔ ∀𝑥∀𝑦(𝑥 ∈ 𝐴 → 𝜑))
4		alcom 2024	. . 3 ⊢ (∀𝑥∀𝑦(𝑥 ∈ 𝐴 → 𝜑) ↔ ∀𝑦∀𝑥(𝑥 ∈ 𝐴 → 𝜑))
5	3, 4	bitri 263	. 2 ⊢ (∀𝑥(𝑥 ∈ 𝐴 → ∀𝑦𝜑) ↔ ∀𝑦∀𝑥(𝑥 ∈ 𝐴 → 𝜑))
6		df-ral 2901	. 2 ⊢ (∀𝑥 ∈ 𝐴 ∀𝑦𝜑 ↔ ∀𝑥(𝑥 ∈ 𝐴 → ∀𝑦𝜑))
7		df-ral 2901	. . 3 ⊢ (∀𝑥 ∈ 𝐴 𝜑 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝜑))
8	7	albii 1737	. 2 ⊢ (∀𝑦∀𝑥 ∈ 𝐴 𝜑 ↔ ∀𝑦∀𝑥(𝑥 ∈ 𝐴 → 𝜑))
9	5, 6, 8	3bitr4i 291	1 ⊢ (∀𝑥 ∈ 𝐴 ∀𝑦𝜑 ↔ ∀𝑦∀𝑥 ∈ 𝐴 𝜑)

Syntax hints:   → wi 4   ↔ wb 195  ∀wal 1473   ∈ wcel 1977  ∀wral 2896

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1713  ax-4 1728  ax-5 1827  ax-11 2021

This theorem depends on definitions:  df-bi 196  df-ex 1696  df-ral 2901

This theorem is referenced by: (None)