Theorem r19.12sn 3436

Description: Special case of r19.12 2422 where its converse holds. (Contributed by NM, 19-May-2008.) (Revised by Mario Carneiro, 23-Apr-2015.)

Hypothesis

Ref	Expression
r19.12sn.1	⊢ 𝐴 ∈ V

Assertion

Ref	Expression
r19.12sn	⊢ (∃𝑥 ∈ {𝐴}∀𝑦 ∈ 𝐵 𝜑 ↔ ∀𝑦 ∈ 𝐵 ∃𝑥 ∈ {𝐴}𝜑)

Distinct variable groups:   𝑥,𝑦,𝐴   𝑥,𝐵

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

Proof of Theorem r19.12sn

Step	Hyp	Ref	Expression
1		r19.12sn.1	. 2 ⊢ 𝐴 ∈ V
2		sbcralg 2836	. . 3 ⊢ (𝐴 ∈ V → ([𝐴 / 𝑥]∀𝑦 ∈ 𝐵 𝜑 ↔ ∀𝑦 ∈ 𝐵 [𝐴 / 𝑥]𝜑))
3		rexsnsOLD 3410	. . 3 ⊢ (𝐴 ∈ V → (∃𝑥 ∈ {𝐴}∀𝑦 ∈ 𝐵 𝜑 ↔ [𝐴 / 𝑥]∀𝑦 ∈ 𝐵 𝜑))
4		rexsnsOLD 3410	. . . 4 ⊢ (𝐴 ∈ V → (∃𝑥 ∈ {𝐴}𝜑 ↔ [𝐴 / 𝑥]𝜑))
5	4	ralbidv 2326	. . 3 ⊢ (𝐴 ∈ V → (∀𝑦 ∈ 𝐵 ∃𝑥 ∈ {𝐴}𝜑 ↔ ∀𝑦 ∈ 𝐵 [𝐴 / 𝑥]𝜑))
6	2, 3, 5	3bitr4d 209	. 2 ⊢ (𝐴 ∈ V → (∃𝑥 ∈ {𝐴}∀𝑦 ∈ 𝐵 𝜑 ↔ ∀𝑦 ∈ 𝐵 ∃𝑥 ∈ {𝐴}𝜑))
7	1, 6	ax-mp 7	1 ⊢ (∃𝑥 ∈ {𝐴}∀𝑦 ∈ 𝐵 𝜑 ↔ ∀𝑦 ∈ 𝐵 ∃𝑥 ∈ {𝐴}𝜑)

Syntax hints:   ↔ wb 98   ∈ wcel 1393  ∀wral 2306  ∃wrex 2307  Vcvv 2557  [wsbc 2764  {csn 3375

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-io 630  ax-5 1336  ax-7 1337  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-8 1395  ax-10 1396  ax-11 1397  ax-i12 1398  ax-bndl 1399  ax-4 1400  ax-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022

This theorem depends on definitions:  df-bi 110  df-tru 1246  df-nf 1350  df-sb 1646  df-clab 2027  df-cleq 2033  df-clel 2036  df-nfc 2167  df-ral 2311  df-rex 2312  df-v 2559  df-sbc 2765  df-sn 3381

This theorem is referenced by: (None)