Theorem r19.27m 3381

Description: Restricted quantifier version of Theorem 19.27 of [Margaris] p. 90. It is valid only when the domain of quantification is inhabited. (Contributed by Jim Kingdon, 5-Aug-2018.)

Hypothesis

Ref	Expression
r19.27m.1	⊢ Ⅎ𝑥𝜓

Assertion

Ref	Expression
r19.27m	⊢ (∃𝑥 𝑥 ∈ 𝐴 → (∀𝑥 ∈ 𝐴 (𝜑 ∧ 𝜓) ↔ (∀𝑥 ∈ 𝐴 𝜑 ∧ 𝜓)))

Distinct variable group:   𝑥,𝐴

Allowed substitution hints:   𝜑(𝑥)   𝜓(𝑥)

Proof of Theorem r19.27m

Step	Hyp	Ref	Expression
1		r19.27m.1	. . . 4 ⊢ Ⅎ𝑥𝜓
2	1	r19.3rm 3374	. . 3 ⊢ (∃𝑥 𝑥 ∈ 𝐴 → (𝜓 ↔ ∀𝑥 ∈ 𝐴 𝜓))
3	2	anbi2d 453	. 2 ⊢ (∃𝑥 𝑥 ∈ 𝐴 → ((∀𝑥 ∈ 𝐴 𝜑 ∧ 𝜓) ↔ (∀𝑥 ∈ 𝐴 𝜑 ∧ ∀𝑥 ∈ 𝐴 𝜓)))
4		r19.26 2498	. 2 ⊢ (∀𝑥 ∈ 𝐴 (𝜑 ∧ 𝜓) ↔ (∀𝑥 ∈ 𝐴 𝜑 ∧ ∀𝑥 ∈ 𝐴 𝜓))
5	3, 4	syl6rbbr 198	1 ⊢ (∃𝑥 𝑥 ∈ 𝐴 → (∀𝑥 ∈ 𝐴 (𝜑 ∧ 𝜓) ↔ (∀𝑥 ∈ 𝐴 𝜑 ∧ 𝜓)))

Syntax hints:   → wi 4   ∧ wa 103   ↔ wb 104  Ⅎwnf 1395  ∃wex 1427   ∈ wcel 1439  ∀wral 2360

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-5 1382  ax-7 1383  ax-gen 1384  ax-ie1 1428  ax-ie2 1429  ax-8 1441  ax-4 1446  ax-17 1465  ax-i9 1469  ax-ial 1473  ax-i5r 1474  ax-ext 2071

This theorem depends on definitions:  df-bi 116  df-nf 1396  df-cleq 2082  df-clel 2085  df-ral 2365

This theorem is referenced by:  r19.27mv  3382  raaanlem  3391