Theorem decidr 16392

Description: Sufficient condition for being decidable in another class. (Contributed by BJ, 19-Feb-2022.)

Hypothesis

Ref	Expression
decidr.1	⊢ (𝜑 → (𝑥 ∈ 𝐵 → (𝑥 ∈ 𝐴 ∨ ¬ 𝑥 ∈ 𝐴)))

Assertion

Ref	Expression
decidr	⊢ (𝜑 → 𝐴 DECIDin 𝐵)

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

Proof of Theorem decidr

Step	Hyp	Ref	Expression
1		decidr.1	. . . 4 ⊢ (𝜑 → (𝑥 ∈ 𝐵 → (𝑥 ∈ 𝐴 ∨ ¬ 𝑥 ∈ 𝐴)))
2		df-dc 842	. . . 4 ⊢ (DECID 𝑥 ∈ 𝐴 ↔ (𝑥 ∈ 𝐴 ∨ ¬ 𝑥 ∈ 𝐴))
3	1, 2	imbitrrdi 162	. . 3 ⊢ (𝜑 → (𝑥 ∈ 𝐵 → DECID 𝑥 ∈ 𝐴))
4	3	alrimiv 1922	. 2 ⊢ (𝜑 → ∀𝑥(𝑥 ∈ 𝐵 → DECID 𝑥 ∈ 𝐴))
5		df-dcin 16390	. . 3 ⊢ (𝐴 DECIDin 𝐵 ↔ ∀𝑥 ∈ 𝐵 DECID 𝑥 ∈ 𝐴)
6		df-ral 2515	. . 3 ⊢ (∀𝑥 ∈ 𝐵 DECID 𝑥 ∈ 𝐴 ↔ ∀𝑥(𝑥 ∈ 𝐵 → DECID 𝑥 ∈ 𝐴))
7	5, 6	bitri 184	. 2 ⊢ (𝐴 DECIDin 𝐵 ↔ ∀𝑥(𝑥 ∈ 𝐵 → DECID 𝑥 ∈ 𝐴))
8	4, 7	sylibr 134	1 ⊢ (𝜑 → 𝐴 DECIDin 𝐵)

Syntax hints:  ¬ wn 3   → wi 4   ∨ wo 715  DECID wdc 841  ∀wal 1395   ∈ wcel 2202  ∀wral 2510   DECID_in wdcin 16389

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-5 1495  ax-gen 1497  ax-17 1574

This theorem depends on definitions:  df-bi 117  df-dc 842  df-ral 2515  df-dcin 16390

This theorem is referenced by:  decidin  16393  uzdcinzz  16394  sumdc2  16395