Theorem iotam 5246

Description: Representation of "the unique element such that 𝜑 " with a class expression 𝐴 which is inhabited (that means that "the unique element such that 𝜑 " exists). (Contributed by AV, 30-Jan-2024.)

Hypothesis

Ref	Expression
iotam.1	⊢ (𝑥 = 𝐴 → (𝜑 ↔ 𝜓))

Assertion

Ref	Expression
iotam	⊢ ((𝐴 ∈ 𝑉 ∧ ∃𝑤 𝑤 ∈ 𝐴 ∧ 𝐴 = (℩𝑥𝜑)) → 𝜓)

Distinct variable groups:   𝑥,𝐴   𝑤,𝐴   𝜓,𝑥

Allowed substitution hints:   𝜑(𝑥,𝑤)   𝜓(𝑤)   𝑉(𝑥,𝑤)

Proof of Theorem iotam

Dummy variable 𝑧 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		eleq1w 2254	. . . . 5 ⊢ (𝑤 = 𝑧 → (𝑤 ∈ 𝐴 ↔ 𝑧 ∈ 𝐴))
2	1	cbvexv 1930	. . . 4 ⊢ (∃𝑤 𝑤 ∈ 𝐴 ↔ ∃𝑧 𝑧 ∈ 𝐴)
3		simprr 531	. . . . . . . 8 ⊢ ((𝑧 ∈ 𝐴 ∧ (𝐴 ∈ 𝑉 ∧ 𝐴 = (℩𝑥𝜑))) → 𝐴 = (℩𝑥𝜑))
4	3	eqcomd 2199	. . . . . . 7 ⊢ ((𝑧 ∈ 𝐴 ∧ (𝐴 ∈ 𝑉 ∧ 𝐴 = (℩𝑥𝜑))) → (℩𝑥𝜑) = 𝐴)
5		simprl 529	. . . . . . . 8 ⊢ ((𝑧 ∈ 𝐴 ∧ (𝐴 ∈ 𝑉 ∧ 𝐴 = (℩𝑥𝜑))) → 𝐴 ∈ 𝑉)
6		simpl 109	. . . . . . . . . 10 ⊢ ((𝑧 ∈ 𝐴 ∧ (𝐴 ∈ 𝑉 ∧ 𝐴 = (℩𝑥𝜑))) → 𝑧 ∈ 𝐴)
7	6, 3	eleqtrd 2272	. . . . . . . . 9 ⊢ ((𝑧 ∈ 𝐴 ∧ (𝐴 ∈ 𝑉 ∧ 𝐴 = (℩𝑥𝜑))) → 𝑧 ∈ (℩𝑥𝜑))
8		eliotaeu 5243	. . . . . . . . 9 ⊢ (𝑧 ∈ (℩𝑥𝜑) → ∃!𝑥𝜑)
9	7, 8	syl 14	. . . . . . . 8 ⊢ ((𝑧 ∈ 𝐴 ∧ (𝐴 ∈ 𝑉 ∧ 𝐴 = (℩𝑥𝜑))) → ∃!𝑥𝜑)
10		iotam.1	. . . . . . . . 9 ⊢ (𝑥 = 𝐴 → (𝜑 ↔ 𝜓))
11	10	iota2 5244	. . . . . . . 8 ⊢ ((𝐴 ∈ 𝑉 ∧ ∃!𝑥𝜑) → (𝜓 ↔ (℩𝑥𝜑) = 𝐴))
12	5, 9, 11	syl2anc 411	. . . . . . 7 ⊢ ((𝑧 ∈ 𝐴 ∧ (𝐴 ∈ 𝑉 ∧ 𝐴 = (℩𝑥𝜑))) → (𝜓 ↔ (℩𝑥𝜑) = 𝐴))
13	4, 12	mpbird 167	. . . . . 6 ⊢ ((𝑧 ∈ 𝐴 ∧ (𝐴 ∈ 𝑉 ∧ 𝐴 = (℩𝑥𝜑))) → 𝜓)
14	13	ex 115	. . . . 5 ⊢ (𝑧 ∈ 𝐴 → ((𝐴 ∈ 𝑉 ∧ 𝐴 = (℩𝑥𝜑)) → 𝜓))
15	14	exlimiv 1609	. . . 4 ⊢ (∃𝑧 𝑧 ∈ 𝐴 → ((𝐴 ∈ 𝑉 ∧ 𝐴 = (℩𝑥𝜑)) → 𝜓))
16	2, 15	sylbi 121	. . 3 ⊢ (∃𝑤 𝑤 ∈ 𝐴 → ((𝐴 ∈ 𝑉 ∧ 𝐴 = (℩𝑥𝜑)) → 𝜓))
17	16	3impib 1203	. 2 ⊢ ((∃𝑤 𝑤 ∈ 𝐴 ∧ 𝐴 ∈ 𝑉 ∧ 𝐴 = (℩𝑥𝜑)) → 𝜓)
18	17	3com12 1209	1 ⊢ ((𝐴 ∈ 𝑉 ∧ ∃𝑤 𝑤 ∈ 𝐴 ∧ 𝐴 = (℩𝑥𝜑)) → 𝜓)

Syntax hints:   → wi 4   ∧ wa 104   ↔ wb 105   ∧ w3a 980   = wceq 1364  ∃wex 1503  ∃!weu 2042   ∈ wcel 2164  ℩cio 5213

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 710  ax-5 1458  ax-7 1459  ax-gen 1460  ax-ie1 1504  ax-ie2 1505  ax-8 1515  ax-10 1516  ax-11 1517  ax-i12 1518  ax-bndl 1520  ax-4 1521  ax-17 1537  ax-i9 1541  ax-ial 1545  ax-i5r 1546  ax-ext 2175

This theorem depends on definitions:  df-bi 117  df-3an 982  df-tru 1367  df-nf 1472  df-sb 1774  df-eu 2045  df-clab 2180  df-cleq 2186  df-clel 2189  df-nfc 2325  df-rex 2478  df-v 2762  df-sbc 2986  df-un 3157  df-sn 3624  df-pr 3625  df-uni 3836  df-iota 5215

This theorem is referenced by:  sgrpidmndm  13001