Theorem riotaprop 6054

Description: Properties of a restricted definite description operator. Todo (df-riota 6028 update): can some uses of riota2f 6051 be shortened with this? (Contributed by NM, 23-Nov-2013.)

Hypotheses

Ref	Expression
riotaprop.0	⊢ Ⅎ𝑥𝜓
riotaprop.1	⊢ 𝐵 = (℩𝑥 ∈ 𝐴 𝜑)
riotaprop.2	⊢ (𝑥 = 𝐵 → (𝜑 ↔ 𝜓))

Assertion

Ref	Expression
riotaprop	⊢ (∃!𝑥 ∈ 𝐴 𝜑 → (𝐵 ∈ 𝐴 ∧ 𝜓))

Distinct variable group:   𝑥,𝐴

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

Proof of Theorem riotaprop

Step	Hyp	Ref	Expression
1		riotaprop.1	. . 3 ⊢ 𝐵 = (℩𝑥 ∈ 𝐴 𝜑)
2		riotacl 6044	. . 3 ⊢ (∃!𝑥 ∈ 𝐴 𝜑 → (℩𝑥 ∈ 𝐴 𝜑) ∈ 𝐴)
3	1, 2	eqeltrid 2325	. 2 ⊢ (∃!𝑥 ∈ 𝐴 𝜑 → 𝐵 ∈ 𝐴)
4	1	eqcomi 2242	. . . 4 ⊢ (℩𝑥 ∈ 𝐴 𝜑) = 𝐵
5		nfriota1 6036	. . . . . 6 ⊢ Ⅎ𝑥(℩𝑥 ∈ 𝐴 𝜑)
6	1, 5	nfcxfr 2389	. . . . 5 ⊢ Ⅎ𝑥𝐵
7		riotaprop.0	. . . . 5 ⊢ Ⅎ𝑥𝜓
8		riotaprop.2	. . . . 5 ⊢ (𝑥 = 𝐵 → (𝜑 ↔ 𝜓))
9	6, 7, 8	riota2f 6051	. . . 4 ⊢ ((𝐵 ∈ 𝐴 ∧ ∃!𝑥 ∈ 𝐴 𝜑) → (𝜓 ↔ (℩𝑥 ∈ 𝐴 𝜑) = 𝐵))
10	4, 9	mpbiri 168	. . 3 ⊢ ((𝐵 ∈ 𝐴 ∧ ∃!𝑥 ∈ 𝐴 𝜑) → 𝜓)
11	3, 10	mpancom 426	. 2 ⊢ (∃!𝑥 ∈ 𝐴 𝜑 → 𝜓)
12	3, 11	jca 306	1 ⊢ (∃!𝑥 ∈ 𝐴 𝜑 → (𝐵 ∈ 𝐴 ∧ 𝜓))

Syntax hints:   → wi 4   ∧ wa 104   ↔ wb 105   = wceq 1402  Ⅎwnf 1513   ∈ wcel 2209  ∃!wreu 2530  ℩crio 6027

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-io 721  ax-5 1500  ax-7 1501  ax-gen 1502  ax-ie1 1546  ax-ie2 1547  ax-8 1557  ax-10 1558  ax-11 1559  ax-i12 1560  ax-bndl 1562  ax-4 1563  ax-17 1579  ax-i9 1583  ax-ial 1587  ax-i5r 1588  ax-ext 2220

This theorem depends on definitions:  df-bi 117  df-3an 1011  df-tru 1405  df-nf 1514  df-sb 1816  df-eu 2089  df-clab 2225  df-cleq 2231  df-clel 2234  df-nfc 2381  df-rex 2534  df-reu 2535  df-rab 2537  df-v 2823  df-sbc 3052  df-un 3224  df-in 3226  df-ss 3233  df-sn 3711  df-pr 3712  df-uni 3931  df-iota 5332  df-riota 6028

This theorem is referenced by:  lble  9267