Theorem prtlem5 36874

Description: Lemma for prter1 36893, prter2 36895, prter3 36896 and prtex 36894. (Contributed by Rodolfo Medina, 25-Sep-2010.) (Proof shortened by Mario Carneiro, 11-Dec-2016.)

Assertion

Ref	Expression
prtlem5	⊢ ([𝑠 / 𝑣][𝑟 / 𝑢]∃𝑥 ∈ 𝐴 (𝑢 ∈ 𝑥 ∧ 𝑣 ∈ 𝑥) ↔ ∃𝑥 ∈ 𝐴 (𝑟 ∈ 𝑥 ∧ 𝑠 ∈ 𝑥))

Distinct variable groups:   𝑣,𝑢,𝑥,𝑟   𝑢,𝑠,𝑣,𝑥   𝑢,𝐴,𝑣,𝑥

Allowed substitution hints:   𝐴(𝑠,𝑟)

Proof of Theorem prtlem5

Step	Hyp	Ref	Expression
1		elequ1 2113	. . . 4 ⊢ (𝑢 = 𝑟 → (𝑢 ∈ 𝑥 ↔ 𝑟 ∈ 𝑥))
2		elequ1 2113	. . . 4 ⊢ (𝑣 = 𝑠 → (𝑣 ∈ 𝑥 ↔ 𝑠 ∈ 𝑥))
3	1, 2	bi2anan9r 637	. . 3 ⊢ ((𝑣 = 𝑠 ∧ 𝑢 = 𝑟) → ((𝑢 ∈ 𝑥 ∧ 𝑣 ∈ 𝑥) ↔ (𝑟 ∈ 𝑥 ∧ 𝑠 ∈ 𝑥)))
4	3	rexbidv 3226	. 2 ⊢ ((𝑣 = 𝑠 ∧ 𝑢 = 𝑟) → (∃𝑥 ∈ 𝐴 (𝑢 ∈ 𝑥 ∧ 𝑣 ∈ 𝑥) ↔ ∃𝑥 ∈ 𝐴 (𝑟 ∈ 𝑥 ∧ 𝑠 ∈ 𝑥)))
5	4	2sbievw 2097	1 ⊢ ([𝑠 / 𝑣][𝑟 / 𝑢]∃𝑥 ∈ 𝐴 (𝑢 ∈ 𝑥 ∧ 𝑣 ∈ 𝑥) ↔ ∃𝑥 ∈ 𝐴 (𝑟 ∈ 𝑥 ∧ 𝑠 ∈ 𝑥))

Syntax hints:   ↔ wb 205   ∧ wa 396  [wsb 2067  ∃wrex 3065

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1798  ax-4 1812  ax-5 1913  ax-6 1971  ax-7 2011  ax-8 2108

This theorem depends on definitions:  df-bi 206  df-an 397  df-ex 1783  df-sb 2068  df-rex 3070

This theorem is referenced by: (None)