P. 368 of Theorem List - Metamath Proof Explorer

Theorem List for Metamath Proof Explorer - 36701-36800   *Has distinct variable group(s)

Type	Label	Description
Statement
Theorem	onelssd 36701	An element of an ordinal number is a subset of the number. Deduction form. (Contributed by Scott Fenton, 31-Jul-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    &   ⊢ (𝜑 → 𝐵 ∈ 𝐴)    ⇒   ⊢ (𝜑 → 𝐵 ⊆ 𝐴)
Theorem	nmulr0d 36702	Natural multiplication by zero. Deduction form. (Contributed by Scott Fenton, 30-Jul-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    ⇒   ⊢ (𝜑 → (𝐴 ·no ∅) = ∅)
Theorem	nmull0d 36703	Natural multiplication by zero. Deduction form. (Contributed by Scott Fenton, 30-Jul-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    ⇒   ⊢ (𝜑 → (∅ ·no 𝐴) = ∅)
Theorem	nmulridd 36704	Identity law for natural multiplication. Deduction form. (Contributed by Scott Fenton, 30-Jul-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    ⇒   ⊢ (𝜑 → (𝐴 ·no 1o) = 𝐴)
Theorem	nmullidd 36705	Identity law for natural multiplication. Deduction form. (Contributed by Scott Fenton, 30-Jul-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    ⇒   ⊢ (𝜑 → (1o ·no 𝐴) = 𝐴)
Theorem	nmulcomd 36706	Natural multiplication commutes. Deduction form. (Contributed by Scott Fenton, 30-Jul-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    &   ⊢ (𝜑 → 𝐵 ∈ On)    ⇒   ⊢ (𝜑 → (𝐴 ·no 𝐵) = (𝐵 ·no 𝐴))
Theorem	naddridd 36707	Identity law for natural addition. Deduction form. (Contributed by Scott Fenton, 30-Jul-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    ⇒   ⊢ (𝜑 → (𝐴 +no ∅) = 𝐴)
Theorem	naddlidd 36708	Identity law for natural addition. Deduction form. (Contributed by Scott Fenton, 30-Jul-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    ⇒   ⊢ (𝜑 → (∅ +no 𝐴) = 𝐴)
Theorem	naddcomd 36709	Natural addition commutes. Deduction form. (Contributed by Scott Fenton, 30-Jul-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    &   ⊢ (𝜑 → 𝐵 ∈ On)    ⇒   ⊢ (𝜑 → (𝐴 +no 𝐵) = (𝐵 +no 𝐴))
Theorem	naddassd 36710	Natural addition associates. Deduction form. (Contributed by Scott Fenton, 30-Jul-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    &   ⊢ (𝜑 → 𝐵 ∈ On)    &   ⊢ (𝜑 → 𝐶 ∈ On)    ⇒   ⊢ (𝜑 → ((𝐴 +no 𝐵) +no 𝐶) = (𝐴 +no (𝐵 +no 𝐶)))
Theorem	nadd32d 36711	Commutative/associative law that swaps the last two terms in a triple sum. Deduction form. (Contributed by Scott Fenton, 30-Jul-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    &   ⊢ (𝜑 → 𝐵 ∈ On)    &   ⊢ (𝜑 → 𝐶 ∈ On)    ⇒   ⊢ (𝜑 → ((𝐴 +no 𝐵) +no 𝐶) = ((𝐴 +no 𝐶) +no 𝐵))
Theorem	nmuladdel 36712	Ordering relationship for natural ordinal operations. (Contributed by Scott Fenton, 15-Jul-2026.)
⊢ (((𝐴 ∈ On ∧ 𝐵 ∈ On) ∧ (𝐶 ∈ 𝐴 ∧ 𝐷 ∈ 𝐵)) → ((𝐶 ·no 𝐵) +no (𝐴 ·no 𝐷)) ∈ ((𝐴 ·no 𝐵) +no (𝐶 ·no 𝐷)))
Theorem	nmuladdss 36713	Ordering relationship for natural ordinal operations. (Contributed by Scott Fenton, 15-Jul-2026.)
⊢ (((𝐴 ∈ On ∧ 𝐵 ∈ On) ∧ (𝐶 ∈ On ∧ 𝐷 ∈ On) ∧ (𝐶 ⊆ 𝐴 ∧ 𝐷 ⊆ 𝐵)) → ((𝐶 ·no 𝐵) +no (𝐴 ·no 𝐷)) ⊆ ((𝐴 ·no 𝐵) +no (𝐶 ·no 𝐷)))
Theorem	nmulss1 36714	Natural multiplication preserves less-than or equal. (Contributed by Scott Fenton, 15-Jul-2026.)
⊢ (((𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On) ∧ 𝐴 ⊆ 𝐵) → (𝐶 ·no 𝐴) ⊆ (𝐶 ·no 𝐵))
Theorem	nmulel1 36715	Natural multiplication by a non-zero number preserves less-than. (Contributed by Scott Fenton, 15-Jul-2026.)
⊢ (((𝐵 ∈ On ∧ 𝐶 ∈ On) ∧ (𝐴 ∈ 𝐵 ∧ 𝐶 ≠ ∅)) → (𝐶 ·no 𝐴) ∈ (𝐶 ·no 𝐵))
Theorem	ltnmul 36716*	Characterize less-than a natural product. (Contributed by Scott Fenton, 15-Jul-2026.)
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On) → (𝐴 ∈ (𝐵 ·no 𝐶) ↔ ∃𝑏 ∈ 𝐵 ∃𝑐 ∈ 𝐶 (𝐴 +no (𝑏 ·no 𝑐)) ⊆ ((𝑏 ·no 𝐶) +no (𝐵 ·no 𝑐))))
Theorem	nmulle 36717*	A condition for bounding a natural product above. Converse of ltnmul 36716. (Contributed by Scott Fenton, 16-Jul-2026.)
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On) → ((𝐴 ·no 𝐵) ⊆ 𝐶 ↔ ∀𝑎 ∈ 𝐴 ∀𝑏 ∈ 𝐵 ((𝑎 ·no 𝐵) +no (𝐴 ·no 𝑏)) ∈ (𝐶 +no (𝑎 ·no 𝑏))))
Theorem	ltnadd 36718*	Condition for bounding a natural sum below. (Contributed by Scott Fenton, 21-Jul-2026.)
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On) → (𝐴 ∈ (𝐵 +no 𝐶) ↔ (∃𝑏 ∈ 𝐵 𝐴 ⊆ (𝑏 +no 𝐶) ∨ ∃𝑐 ∈ 𝐶 𝐴 ⊆ (𝐵 +no 𝑐))))
Theorem	naddle 36719*	Condition for bounding natural addition above. (Contributed by Scott Fenton, 21-Jul-2026.)
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On) → ((𝐴 +no 𝐵) ⊆ 𝐶 ↔ (∀𝑎 ∈ 𝐴 (𝑎 +no 𝐵) ∈ 𝐶 ∧ ∀𝑏 ∈ 𝐵 (𝐴 +no 𝑏) ∈ 𝐶)))
Theorem	nadddilem1 36720*	Lemma for nadddi 36724. Prove a subcase of the reverse implication. (Contributed by Scott Fenton, 31-Jul-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    &   ⊢ (𝜑 → 𝐵 ∈ On)    &   ⊢ (𝜑 → 𝐶 ∈ On)    &   ⊢ (𝜑 → ∀𝑑 ∈ 𝐴 (𝑑 ·no (𝐵 +no 𝐶)) = ((𝑑 ·no 𝐵) +no (𝑑 ·no 𝐶)))    &   ⊢ (𝜑 → ∀𝑓 ∈ 𝐶 (𝐴 ·no (𝐵 +no 𝑓)) = ((𝐴 ·no 𝐵) +no (𝐴 ·no 𝑓)))    &   ⊢ (𝜑 → ∀𝑑 ∈ 𝐴 ∀𝑓 ∈ 𝐶 (𝑑 ·no (𝐵 +no 𝑓)) = ((𝑑 ·no 𝐵) +no (𝑑 ·no 𝑓)))    ⇒   ⊢ ((𝜑 ∧ 𝑌 ∈ (𝐴 ·no 𝐶)) → ((𝐴 ·no 𝐵) +no 𝑌) ∈ (𝐴 ·no (𝐵 +no 𝐶)))
Theorem	nadddilem2 36721*	Lemma for nadddi 36724. Prove the reverse implication. (Contributed by Scott Fenton, 31-Jul-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    &   ⊢ (𝜑 → 𝐵 ∈ On)    &   ⊢ (𝜑 → 𝐶 ∈ On)    &   ⊢ (𝜑 → ∀𝑑 ∈ 𝐴 (𝑑 ·no (𝐵 +no 𝐶)) = ((𝑑 ·no 𝐵) +no (𝑑 ·no 𝐶)))    &   ⊢ (𝜑 → ∀𝑒 ∈ 𝐵 (𝐴 ·no (𝑒 +no 𝐶)) = ((𝐴 ·no 𝑒) +no (𝐴 ·no 𝐶)))    &   ⊢ (𝜑 → ∀𝑓 ∈ 𝐶 (𝐴 ·no (𝐵 +no 𝑓)) = ((𝐴 ·no 𝐵) +no (𝐴 ·no 𝑓)))    &   ⊢ (𝜑 → ∀𝑑 ∈ 𝐴 ∀𝑒 ∈ 𝐵 (𝑑 ·no (𝑒 +no 𝐶)) = ((𝑑 ·no 𝑒) +no (𝑑 ·no 𝐶)))    &   ⊢ (𝜑 → ∀𝑑 ∈ 𝐴 ∀𝑓 ∈ 𝐶 (𝑑 ·no (𝐵 +no 𝑓)) = ((𝑑 ·no 𝐵) +no (𝑑 ·no 𝑓)))    ⇒   ⊢ (𝜑 → ((𝐴 ·no 𝐵) +no (𝐴 ·no 𝐶)) ⊆ (𝐴 ·no (𝐵 +no 𝐶)))
Theorem	nadddilem3 36722*	Lemma for nadddi 36724. Prove a subcase of the forward implication. (Contributed by Scott Fenton, 3-Aug-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    &   ⊢ (𝜑 → 𝐵 ∈ On)    &   ⊢ (𝜑 → 𝐶 ∈ On)    &   ⊢ (𝜑 → 𝑋 ∈ 𝐴)    &   ⊢ (𝜑 → 𝑌 ∈ (𝐵 +no 𝐶))    &   ⊢ (𝜑 → 𝑍 ∈ 𝐵)    &   ⊢ (𝜑 → 𝑌 ⊆ (𝑍 +no 𝐶))    &   ⊢ (𝜑 → ∀𝑑 ∈ 𝐴 (𝑑 ·no (𝐵 +no 𝐶)) = ((𝑑 ·no 𝐵) +no (𝑑 ·no 𝐶)))    &   ⊢ (𝜑 → ∀𝑒 ∈ 𝐵 (𝐴 ·no (𝑒 +no 𝐶)) = ((𝐴 ·no 𝑒) +no (𝐴 ·no 𝐶)))    &   ⊢ (𝜑 → ∀𝑑 ∈ 𝐴 ∀𝑒 ∈ 𝐵 (𝑑 ·no (𝑒 +no 𝐶)) = ((𝑑 ·no 𝑒) +no (𝑑 ·no 𝐶)))    ⇒   ⊢ (𝜑 → ((𝑋 ·no (𝐵 +no 𝐶)) +no (𝐴 ·no 𝑌)) ∈ (((𝐴 ·no 𝐵) +no (𝐴 ·no 𝐶)) +no (𝑋 ·no 𝑌)))
Theorem	nadddilem4 36723*	Lemma for nadddi 36724. Prove the forward implication. (Contributed by Scott Fenton, 3-Aug-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    &   ⊢ (𝜑 → 𝐵 ∈ On)    &   ⊢ (𝜑 → 𝐶 ∈ On)    &   ⊢ (𝜑 → ∀𝑑 ∈ 𝐴 (𝑑 ·no (𝐵 +no 𝐶)) = ((𝑑 ·no 𝐵) +no (𝑑 ·no 𝐶)))    &   ⊢ (𝜑 → ∀𝑒 ∈ 𝐵 (𝐴 ·no (𝑒 +no 𝐶)) = ((𝐴 ·no 𝑒) +no (𝐴 ·no 𝐶)))    &   ⊢ (𝜑 → ∀𝑓 ∈ 𝐶 (𝐴 ·no (𝐵 +no 𝑓)) = ((𝐴 ·no 𝐵) +no (𝐴 ·no 𝑓)))    &   ⊢ (𝜑 → ∀𝑑 ∈ 𝐴 ∀𝑒 ∈ 𝐵 (𝑑 ·no (𝑒 +no 𝐶)) = ((𝑑 ·no 𝑒) +no (𝑑 ·no 𝐶)))    &   ⊢ (𝜑 → ∀𝑑 ∈ 𝐴 ∀𝑓 ∈ 𝐶 (𝑑 ·no (𝐵 +no 𝑓)) = ((𝑑 ·no 𝐵) +no (𝑑 ·no 𝑓)))    ⇒   ⊢ (𝜑 → (𝐴 ·no (𝐵 +no 𝐶)) ⊆ ((𝐴 ·no 𝐵) +no (𝐴 ·no 𝐶)))
Theorem	nadddi 36724	Natural multiplication distributes over natural addition. (Contributed by Scott Fenton, 27-Jul-2026.)
⊢ ((𝐴 ∈ On ∧ 𝐵 ∈ On ∧ 𝐶 ∈ On) → (𝐴 ·no (𝐵 +no 𝐶)) = ((𝐴 ·no 𝐵) +no (𝐴 ·no 𝐶)))
Theorem	nadddid 36725	Natural multiplication distributes over natural addition. Deduction form. (Contributed by Scott Fenton, 3-Aug-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    &   ⊢ (𝜑 → 𝐵 ∈ On)    &   ⊢ (𝜑 → 𝐶 ∈ On)    ⇒   ⊢ (𝜑 → (𝐴 ·no (𝐵 +no 𝐶)) = ((𝐴 ·no 𝐵) +no (𝐴 ·no 𝐶)))
Theorem	nadddird 36726	Natural multiplication distributes over natural addition. Deduction form. (Contributed by Scott Fenton, 3-Aug-2026.)
⊢ (𝜑 → 𝐴 ∈ On)    &   ⊢ (𝜑 → 𝐵 ∈ On)    &   ⊢ (𝜑 → 𝐶 ∈ On)    ⇒   ⊢ (𝜑 → ((𝐴 +no 𝐵) ·no 𝐶) = ((𝐴 ·no 𝐶) +no (𝐵 ·no 𝐶)))
21.12  Mathbox for Gino Giotto
21.12.1  Equality theorems
21.12.1.1  Inference versions
Theorem	rmoeqi 36727	Equality inference for restricted at-most-one quantifier. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    ⇒   ⊢ (∃*𝑥 ∈ 𝐴 𝜓 ↔ ∃*𝑥 ∈ 𝐵 𝜓)
Theorem	rmoeqbii 36728	Equality inference for restricted at-most-one quantifier. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ (𝜓 ↔ 𝜒)    ⇒   ⊢ (∃*𝑥 ∈ 𝐴 𝜓 ↔ ∃*𝑥 ∈ 𝐵 𝜒)
Theorem	reueqi 36729	Equality inference for restricted existential uniqueness quantifier. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    ⇒   ⊢ (∃!𝑥 ∈ 𝐴 𝜓 ↔ ∃!𝑥 ∈ 𝐵 𝜓)
Theorem	reueqbii 36730	Equality inference for restricted existential uniqueness quantifier. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ (𝜓 ↔ 𝜒)    ⇒   ⊢ (∃!𝑥 ∈ 𝐴 𝜓 ↔ ∃!𝑥 ∈ 𝐵 𝜒)
Theorem	sbceqbii 36731	Formula-building inference for class substitution. General version of sbcbii 3799. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ (𝜑 ↔ 𝜓)    ⇒   ⊢ ([𝐴 / 𝑥]𝜑 ↔ [𝐵 / 𝑥]𝜓)
Theorem	disjeq1i 36732	Equality theorem for disjoint collection. Inference version. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    ⇒   ⊢ (Disj 𝑥 ∈ 𝐴 𝐶 ↔ Disj 𝑥 ∈ 𝐵 𝐶)
Theorem	disjeq12i 36733	Equality theorem for disjoint collection. Inference version. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ 𝐶 = 𝐷    ⇒   ⊢ (Disj 𝑥 ∈ 𝐴 𝐶 ↔ Disj 𝑥 ∈ 𝐵 𝐷)
Theorem	rabeqbii 36734	Equality theorem for restricted class abstractions. Inference version. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ (𝜑 ↔ 𝜓)    ⇒   ⊢ {𝑥 ∈ 𝐴 ∣ 𝜑} = {𝑥 ∈ 𝐵 ∣ 𝜓}
Theorem	iuneq12i 36735	Equality theorem for indexed union. Inference version. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ 𝐶 = 𝐷    ⇒   ⊢ ∪ 𝑥 ∈ 𝐴 𝐶 = ∪ 𝑥 ∈ 𝐵 𝐷
Theorem	iineq1i 36736	Equality theorem for indexed intersection. Inference version. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    ⇒   ⊢ ∩ 𝑥 ∈ 𝐴 𝐶 = ∩ 𝑥 ∈ 𝐵 𝐶
Theorem	iineq12i 36737	Equality theorem for indexed intersection. Inference version. General version of iineq1i 36736. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ 𝐶 = 𝐷    ⇒   ⊢ ∩ 𝑥 ∈ 𝐴 𝐶 = ∩ 𝑥 ∈ 𝐵 𝐷
Theorem	riotaeqbii 36738	Equivalent wff's and equal domains yield equal restricted iotas. Inference version. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ (𝜑 ↔ 𝜓)    ⇒   ⊢ (℩𝑥 ∈ 𝐴 𝜑) = (℩𝑥 ∈ 𝐵 𝜓)
Theorem	riotaeqi 36739	Equal domains yield equal restricted iotas. Inference version. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    ⇒   ⊢ (℩𝑥 ∈ 𝐴 𝜑) = (℩𝑥 ∈ 𝐵 𝜑)
Theorem	ixpeq1i 36740	Equality inference for infinite Cartesian product. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    ⇒   ⊢ X𝑥 ∈ 𝐴 𝐶 = X𝑥 ∈ 𝐵 𝐶
Theorem	ixpeq12i 36741	Equality inference for infinite Cartesian product. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ 𝐶 = 𝐷    ⇒   ⊢ X𝑥 ∈ 𝐴 𝐶 = X𝑥 ∈ 𝐵 𝐷
Theorem	sumeq2si 36742	Equality inference for sum. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐵 = 𝐶    ⇒   ⊢ Σ𝑘 ∈ 𝐴 𝐵 = Σ𝑘 ∈ 𝐴 𝐶
Theorem	sumeq12si 36743	Equality inference for sum. General version of sumeq2si 36742. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ 𝐶 = 𝐷    ⇒   ⊢ Σ𝑥 ∈ 𝐴 𝐶 = Σ𝑥 ∈ 𝐵 𝐷
Theorem	prodeq2si 36744	Equality inference for product. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐵 = 𝐶    ⇒   ⊢ ∏𝑘 ∈ 𝐴 𝐵 = ∏𝑘 ∈ 𝐴 𝐶
Theorem	prodeq12si 36745	Equality inference for product. General version of prodeq2si 36744. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ 𝐶 = 𝐷    ⇒   ⊢ ∏𝑥 ∈ 𝐴 𝐶 = ∏𝑥 ∈ 𝐵 𝐷
Theorem	itgeq12i 36746	Equality inference for an integral. General version of itgeq1i 36747 and itgeq2i 36748. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ 𝐶 = 𝐷    ⇒   ⊢ ∫𝐴𝐶 d𝑥 = ∫𝐵𝐷 d𝑥
Theorem	itgeq1i 36747	Equality inference for an integral. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    ⇒   ⊢ ∫𝐴𝐶 d𝑥 = ∫𝐵𝐶 d𝑥
Theorem	itgeq2i 36748	Equality inference for an integral. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐵 = 𝐶    ⇒   ⊢ ∫𝐴𝐵 d𝑥 = ∫𝐴𝐶 d𝑥
Theorem	ditgeq123i 36749	Equality inference for the directed integral. General version of ditgeq12i 36750 and ditgeq3i 36751. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ 𝐶 = 𝐷    &   ⊢ 𝐸 = 𝐹    ⇒   ⊢ ⨜[𝐴 → 𝐶]𝐸 d𝑥 = ⨜[𝐵 → 𝐷]𝐹 d𝑥
Theorem	ditgeq12i 36750	Equality inference for the directed integral. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ 𝐶 = 𝐷    ⇒   ⊢ ⨜[𝐴 → 𝐶]𝐸 d𝑥 = ⨜[𝐵 → 𝐷]𝐸 d𝑥
Theorem	ditgeq3i 36751	Equality inference for the directed integral. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐶 = 𝐷    ⇒   ⊢ ⨜[𝐴 → 𝐵]𝐶 d𝑥 = ⨜[𝐴 → 𝐵]𝐷 d𝑥
21.12.1.2  Deduction versions
Theorem	rmoeqdv 36752*	Formula-building rule for restricted at-most-one quantifier. Deduction form. (Contributed by GG, 1-Sep-2025.)
⊢ (𝜑 → 𝐴 = 𝐵)    ⇒   ⊢ (𝜑 → (∃*𝑥 ∈ 𝐴 𝜓 ↔ ∃*𝑥 ∈ 𝐵 𝜓))
Theorem	rmoeqbidv 36753*	Formula-building rule for restricted at-most-one quantifier. Deduction form. General version of rmobidv 3383. (Contributed by GG, 1-Sep-2025.)
⊢ (𝜑 → 𝐴 = 𝐵)    &   ⊢ (𝜑 → (𝜓 ↔ 𝜒))    ⇒   ⊢ (𝜑 → (∃*𝑥 ∈ 𝐴 𝜓 ↔ ∃*𝑥 ∈ 𝐵 𝜒))
Theorem	sbequbidv 36754*	Deduction substituting both sides of a biconditional. (Contributed by GG, 1-Sep-2025.)
⊢ (𝜑 → 𝑢 = 𝑣)    &   ⊢ (𝜑 → (𝜓 ↔ 𝜒))    ⇒   ⊢ (𝜑 → ([𝑢 / 𝑥]𝜓 ↔ [𝑣 / 𝑥]𝜒))
Theorem	disjeq12dv 36755*	Equality theorem for disjoint collection. Deduction version. (Contributed by GG, 1-Sep-2025.)
⊢ (𝜑 → 𝐴 = 𝐵)    &   ⊢ (𝜑 → 𝐶 = 𝐷)    ⇒   ⊢ (𝜑 → (Disj 𝑥 ∈ 𝐴 𝐶 ↔ Disj 𝑥 ∈ 𝐵 𝐷))
Theorem	ixpeq12dv 36756*	Equality theorem for infinite Cartesian product. Deduction version. (Contributed by GG, 1-Sep-2025.)
⊢ (𝜑 → 𝐴 = 𝐵)    &   ⊢ (𝜑 → 𝐶 = 𝐷)    ⇒   ⊢ (𝜑 → X𝑥 ∈ 𝐴 𝐶 = X𝑥 ∈ 𝐵 𝐷)
Theorem	sumeq12sdv 36757*	Equality deduction for sum. General version of sumeq2sdv 15761. (Contributed by GG, 1-Sep-2025.)
⊢ (𝜑 → 𝐴 = 𝐵)    &   ⊢ (𝜑 → 𝐶 = 𝐷)    ⇒   ⊢ (𝜑 → Σ𝑘 ∈ 𝐴 𝐶 = Σ𝑘 ∈ 𝐵 𝐷)
Theorem	prodeq12sdv 36758*	Equality deduction for product. General version of prodeq2sdv 15984. (Contributed by GG, 1-Sep-2025.)
⊢ (𝜑 → 𝐴 = 𝐵)    &   ⊢ (𝜑 → 𝐶 = 𝐷)    ⇒   ⊢ (𝜑 → ∏𝑘 ∈ 𝐴 𝐶 = ∏𝑘 ∈ 𝐵 𝐷)
Theorem	itgeq12sdv 36759*	Equality theorem for an integral. Deduction form. General version of itgeq1d 46699 and itgeq2sdv 36760. (Contributed by GG, 1-Sep-2025.)
⊢ (𝜑 → 𝐴 = 𝐵)    &   ⊢ (𝜑 → 𝐶 = 𝐷)    ⇒   ⊢ (𝜑 → ∫𝐴𝐶 d𝑥 = ∫𝐵𝐷 d𝑥)
Theorem	itgeq2sdv 36760*	Equality theorem for an integral. Deduction form. (Contributed by GG, 1-Sep-2025.)
⊢ (𝜑 → 𝐵 = 𝐶)    ⇒   ⊢ (𝜑 → ∫𝐴𝐵 d𝑥 = ∫𝐴𝐶 d𝑥)
Theorem	ditgeq123dv 36761*	Equality theorem for the directed integral. Deduction form. General version of ditgeq3sdv 36763. (Contributed by GG, 1-Sep-2025.)
⊢ (𝜑 → 𝐴 = 𝐵)    &   ⊢ (𝜑 → 𝐶 = 𝐷)    &   ⊢ (𝜑 → 𝐸 = 𝐹)    ⇒   ⊢ (𝜑 → ⨜[𝐴 → 𝐶]𝐸 d𝑥 = ⨜[𝐵 → 𝐷]𝐹 d𝑥)
Theorem	ditgeq12d 36762*	Equality theorem for the directed integral. Deduction form. (Contributed by GG, 1-Sep-2025.)
⊢ (𝜑 → 𝐴 = 𝐵)    &   ⊢ (𝜑 → 𝐶 = 𝐷)    ⇒   ⊢ (𝜑 → ⨜[𝐴 → 𝐶]𝐸 d𝑥 = ⨜[𝐵 → 𝐷]𝐸 d𝑥)
Theorem	ditgeq3sdv 36763*	Equality theorem for the directed integral. Deduction form. (Contributed by GG, 1-Sep-2025.)
⊢ (𝜑 → 𝐶 = 𝐷)    ⇒   ⊢ (𝜑 → ⨜[𝐴 → 𝐵]𝐶 d𝑥 = ⨜[𝐴 → 𝐵]𝐷 d𝑥)
21.12.2  Change bound variables
Theorem	in-ax8 36764	A proof of ax-8 2144 that does not rely on ax-8 2144. It employs df-in 3911 to perform alpha-renaming and eliminates disjoint variable conditions using ax-9 2152. Since the nature of this result is unclear, usage of this theorem is discouraged, and this method should not be applied to eliminate axiom dependencies. (Contributed by GG, 1-Aug-2025.) (Proof modification is discouraged.) (New usage is discouraged.)
⊢ (𝑥 = 𝑦 → (𝑥 ∈ 𝑧 → 𝑦 ∈ 𝑧))
Theorem	ss-ax8 36765	A proof of ax-8 2144 that does not rely on ax-8 2144. It employs df-ss 3921 to perform alpha-renaming and eliminates disjoint variable conditions using ax-9 2152. Contrary to in-ax8 36764, this proof does not rely on df-cleq 2754, therefore using fewer axioms . This method should not be applied to eliminate axiom dependencies. (Contributed by GG, 30-Aug-2025.) (Proof modification is discouraged.) (New usage is discouraged.)
⊢ (𝑥 = 𝑦 → (𝑥 ∈ 𝑧 → 𝑦 ∈ 𝑧))
21.12.2.1  Change bound variables and domains
Theorem	cbvralvw2 36766*	Change bound variable and domain in the restricted universal quantifier, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ (𝑥 = 𝑦 → 𝐴 = 𝐵)    &   ⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓))    ⇒   ⊢ (∀𝑥 ∈ 𝐴 𝜑 ↔ ∀𝑦 ∈ 𝐵 𝜓)
Theorem	cbvrexvw2 36767*	Change bound variable and domain in the restricted existential quantifier, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ (𝑥 = 𝑦 → 𝐴 = 𝐵)    &   ⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓))    ⇒   ⊢ (∃𝑥 ∈ 𝐴 𝜑 ↔ ∃𝑦 ∈ 𝐵 𝜓)
Theorem	cbvrmovw2 36768*	Change bound variable and domain in the restricted at-most-one quantifier, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ (𝑥 = 𝑦 → 𝐴 = 𝐵)    &   ⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓))    ⇒   ⊢ (∃*𝑥 ∈ 𝐴 𝜑 ↔ ∃*𝑦 ∈ 𝐵 𝜓)
Theorem	cbvreuvw2 36769*	Change bound variable and domain in the restricted existential uniqueness quantifier, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ (𝑥 = 𝑦 → 𝐴 = 𝐵)    &   ⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓))    ⇒   ⊢ (∃!𝑥 ∈ 𝐴 𝜑 ↔ ∃!𝑦 ∈ 𝐵 𝜓)
Theorem	cbvsbcvw2 36770*	Change bound variable of a class substitution using implicit substitution. General version of cbvsbcvw 3777. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓))    ⇒   ⊢ ([𝐴 / 𝑥]𝜑 ↔ [𝐵 / 𝑦]𝜓)
Theorem	cbvcsbvw2 36771*	Change bound variable of a proper substitution into a class using implicit substitution. General version of cbvcsbv 3864. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ (𝑥 = 𝑦 → 𝐶 = 𝐷)    ⇒   ⊢ ⦋𝐴 / 𝑥⦌𝐶 = ⦋𝐵 / 𝑦⦌𝐷
Theorem	cbviunvw2 36772*	Change bound variable and domain in indexed unions, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ (𝑥 = 𝑦 → 𝐶 = 𝐷)    &   ⊢ (𝑥 = 𝑦 → 𝐴 = 𝐵)    ⇒   ⊢ ∪ 𝑥 ∈ 𝐴 𝐶 = ∪ 𝑦 ∈ 𝐵 𝐷
Theorem	cbviinvw2 36773*	Change bound variable and domain in an indexed intersection, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ (𝑥 = 𝑦 → 𝐶 = 𝐷)    &   ⊢ (𝑥 = 𝑦 → 𝐴 = 𝐵)    ⇒   ⊢ ∩ 𝑥 ∈ 𝐴 𝐶 = ∩ 𝑦 ∈ 𝐵 𝐷
Theorem	cbvmptvw2 36774*	Change bound variable and domain in a maps-to function, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ (𝑥 = 𝑦 → 𝐶 = 𝐷)    &   ⊢ (𝑥 = 𝑦 → 𝐴 = 𝐵)    ⇒   ⊢ (𝑥 ∈ 𝐴 ↦ 𝐶) = (𝑦 ∈ 𝐵 ↦ 𝐷)
Theorem	cbvdisjvw2 36775*	Change bound variable and domain in a disjoint collection, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ (𝑥 = 𝑦 → 𝐶 = 𝐷)    &   ⊢ (𝑥 = 𝑦 → 𝐴 = 𝐵)    ⇒   ⊢ (Disj 𝑥 ∈ 𝐴 𝐶 ↔ Disj 𝑦 ∈ 𝐵 𝐷)
Theorem	cbvriotavw2 36776*	Change bound variable and domain in a restricted description binder, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ (𝑥 = 𝑦 → 𝐴 = 𝐵)    &   ⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓))    ⇒   ⊢ (℩𝑥 ∈ 𝐴 𝜑) = (℩𝑦 ∈ 𝐵 𝜓)
Theorem	cbvoprab1vw 36777*	Change the first bound variable in an operation abstraction, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ (𝑥 = 𝑤 → (𝜓 ↔ 𝜒))    ⇒   ⊢ {⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∣ 𝜓} = {⟨⟨𝑤, 𝑦⟩, 𝑧⟩ ∣ 𝜒}
Theorem	cbvoprab2vw 36778*	Change the second bound variable in an operation abstraction, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ (𝑦 = 𝑤 → (𝜓 ↔ 𝜒))    ⇒   ⊢ {⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∣ 𝜓} = {⟨⟨𝑥, 𝑤⟩, 𝑧⟩ ∣ 𝜒}
Theorem	cbvoprab123vw 36779*	Change all bound variables in an operation abstraction, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ (((𝑥 = 𝑤 ∧ 𝑦 = 𝑢) ∧ 𝑧 = 𝑣) → (𝜓 ↔ 𝜒))    ⇒   ⊢ {⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∣ 𝜓} = {⟨⟨𝑤, 𝑢⟩, 𝑣⟩ ∣ 𝜒}
Theorem	cbvoprab23vw 36780*	Change the second and third bound variables in an operation abstraction, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ ((𝑦 = 𝑤 ∧ 𝑧 = 𝑣) → (𝜓 ↔ 𝜒))    ⇒   ⊢ {⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∣ 𝜓} = {⟨⟨𝑥, 𝑤⟩, 𝑣⟩ ∣ 𝜒}
Theorem	cbvoprab13vw 36781*	Change the first and third bound variables in an operation abstraction, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ ((𝑥 = 𝑤 ∧ 𝑧 = 𝑣) → (𝜓 ↔ 𝜒))    ⇒   ⊢ {⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∣ 𝜓} = {⟨⟨𝑤, 𝑦⟩, 𝑣⟩ ∣ 𝜒}
Theorem	cbvmpovw2 36782*	Change bound variables and domains in a maps-to function, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ ((𝑥 = 𝑧 ∧ 𝑦 = 𝑤) → 𝐸 = 𝐹)    &   ⊢ ((𝑥 = 𝑧 ∧ 𝑦 = 𝑤) → 𝐶 = 𝐷)    &   ⊢ ((𝑥 = 𝑧 ∧ 𝑦 = 𝑤) → 𝐴 = 𝐵)    ⇒   ⊢ (𝑥 ∈ 𝐴, 𝑦 ∈ 𝐶 ↦ 𝐸) = (𝑧 ∈ 𝐵, 𝑤 ∈ 𝐷 ↦ 𝐹)
Theorem	cbvmpo1vw2 36783*	Change domains and the first bound variable in a maps-to function, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ (𝑥 = 𝑧 → 𝐸 = 𝐹)    &   ⊢ (𝑥 = 𝑧 → 𝐶 = 𝐷)    &   ⊢ (𝑥 = 𝑧 → 𝐴 = 𝐵)    ⇒   ⊢ (𝑥 ∈ 𝐴, 𝑦 ∈ 𝐶 ↦ 𝐸) = (𝑧 ∈ 𝐵, 𝑦 ∈ 𝐷 ↦ 𝐹)
Theorem	cbvmpo2vw2 36784*	Change domains and the second bound variable in a maps-to function, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ (𝑦 = 𝑧 → 𝐸 = 𝐹)    &   ⊢ (𝑦 = 𝑧 → 𝐶 = 𝐷)    &   ⊢ (𝑦 = 𝑧 → 𝐴 = 𝐵)    ⇒   ⊢ (𝑥 ∈ 𝐴, 𝑦 ∈ 𝐶 ↦ 𝐸) = (𝑥 ∈ 𝐵, 𝑧 ∈ 𝐷 ↦ 𝐹)
Theorem	cbvixpvw2 36785*	Change bound variable and domain in an indexed Cartesian product, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ (𝑥 = 𝑦 → 𝐶 = 𝐷)    &   ⊢ (𝑥 = 𝑦 → 𝐴 = 𝐵)    ⇒   ⊢ X𝑥 ∈ 𝐴 𝐶 = X𝑦 ∈ 𝐵 𝐷
Theorem	cbvsumvw2 36786*	Change bound variable and the set of integers in a sum, using implicit substitution. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ (𝑗 = 𝑘 → 𝐶 = 𝐷)    ⇒   ⊢ Σ𝑗 ∈ 𝐴 𝐶 = Σ𝑘 ∈ 𝐵 𝐷
Theorem	cbvprodvw2 36787*	Change bound variable and the set of integers in a product, using implicit substitution. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ (𝑗 = 𝑘 → 𝐶 = 𝐷)    ⇒   ⊢ ∏𝑗 ∈ 𝐴 𝐶 = ∏𝑘 ∈ 𝐵 𝐷
Theorem	cbvitgvw2 36788*	Change bound variable and domain in an integral, using implicit substitution. (Contributed by GG, 14-Aug-2025.)
⊢ (𝑥 = 𝑦 → 𝐶 = 𝐷)    &   ⊢ (𝑥 = 𝑦 → 𝐴 = 𝐵)    ⇒   ⊢ ∫𝐴𝐶 d𝑥 = ∫𝐵𝐷 d𝑦
Theorem	cbvditgvw2 36789*	Change bound variable and domain in a directed integral, using implicit substitution. (Contributed by GG, 1-Sep-2025.)
⊢ 𝐴 = 𝐵    &   ⊢ 𝐶 = 𝐷    &   ⊢ (𝑥 = 𝑦 → 𝐸 = 𝐹)    ⇒   ⊢ ⨜[𝐴 → 𝐶]𝐸 d𝑥 = ⨜[𝐵 → 𝐷]𝐹 d𝑦
21.12.2.2  Change bound variables, deduction versions
Theorem	cbvmodavw 36790*	Change bound variable in the at-most-one quantifier. Deduction form. (Contributed by GG, 14-Aug-2025.)
⊢ ((𝜑 ∧ 𝑥 = 𝑦) → (𝜓 ↔ 𝜒))    ⇒   ⊢ (𝜑 → (∃*𝑥𝜓 ↔ ∃*𝑦𝜒))
Theorem	cbveudavw 36791*	Change bound variable in the existential uniqueness quantifier. Deduction form. (Contributed by GG, 14-Aug-2025.)
⊢ ((𝜑 ∧ 𝑥 = 𝑦) → (𝜓 ↔ 𝜒))    ⇒   ⊢ (𝜑 → (∃!𝑥𝜓 ↔ ∃!𝑦𝜒))
Theorem	cbvrmodavw 36792*	Change bound variable in the restricted at-most-one quantifier. Deduction form. (Contributed by GG, 14-Aug-2025.)
⊢ ((𝜑 ∧ 𝑥 = 𝑦) → (𝜓 ↔ 𝜒))    ⇒   ⊢ (𝜑 → (∃*𝑥 ∈ 𝐴 𝜓 ↔ ∃*𝑦 ∈ 𝐴 𝜒))
Theorem	cbvreudavw 36793*	Change bound variable in the restricted existential uniqueness quantifier. Deduction form. (Contributed by GG, 14-Aug-2025.)
⊢ ((𝜑 ∧ 𝑥 = 𝑦) → (𝜓 ↔ 𝜒))    ⇒   ⊢ (𝜑 → (∃!𝑥 ∈ 𝐴 𝜓 ↔ ∃!𝑦 ∈ 𝐴 𝜒))
Theorem	cbvsbdavw 36794*	Change bound variable in proper substitution. Deduction form. (Contributed by GG, 14-Aug-2025.)
⊢ ((𝜑 ∧ 𝑥 = 𝑦) → (𝜓 ↔ 𝜒))    ⇒   ⊢ (𝜑 → ([𝑧 / 𝑥]𝜓 ↔ [𝑧 / 𝑦]𝜒))
Theorem	cbvsbdavw2 36795*	Change bound variable in proper substitution. General version of cbvsbdavw 36794. Deduction form. (Contributed by GG, 14-Aug-2025.)
⊢ (𝜑 → 𝑧 = 𝑤)    &   ⊢ ((𝜑 ∧ 𝑥 = 𝑦) → (𝜓 ↔ 𝜒))    ⇒   ⊢ (𝜑 → ([𝑧 / 𝑥]𝜓 ↔ [𝑤 / 𝑦]𝜒))
Theorem	cbvabdavw 36796*	Change bound variable in class abstractions. Deduction form. (Contributed by GG, 14-Aug-2025.)
⊢ ((𝜑 ∧ 𝑥 = 𝑦) → (𝜓 ↔ 𝜒))    ⇒   ⊢ (𝜑 → {𝑥 ∣ 𝜓} = {𝑦 ∣ 𝜒})
Theorem	cbvsbcdavw 36797*	Change bound variable of a class substitution. Deduction form. (Contributed by GG, 14-Aug-2025.)
⊢ ((𝜑 ∧ 𝑥 = 𝑦) → (𝜓 ↔ 𝜒))    ⇒   ⊢ (𝜑 → ([𝐴 / 𝑥]𝜓 ↔ [𝐴 / 𝑦]𝜒))
Theorem	cbvsbcdavw2 36798*	Change bound variable of a class substitution. General version of cbvsbcdavw 36797. Deduction form. (Contributed by GG, 14-Aug-2025.)
⊢ (𝜑 → 𝐴 = 𝐵)    &   ⊢ ((𝜑 ∧ 𝑥 = 𝑦) → (𝜓 ↔ 𝜒))    ⇒   ⊢ (𝜑 → ([𝐴 / 𝑥]𝜓 ↔ [𝐵 / 𝑦]𝜒))
Theorem	cbvcsbdavw 36799*	Change bound variable of a proper substitution into a class. Deduction form. (Contributed by GG, 14-Aug-2025.)
⊢ ((𝜑 ∧ 𝑥 = 𝑦) → 𝐵 = 𝐶)    ⇒   ⊢ (𝜑 → ⦋𝐴 / 𝑥⦌𝐵 = ⦋𝐴 / 𝑦⦌𝐶)
Theorem	cbvcsbdavw2 36800*	Change bound variable of a proper substitution into a class. General version of cbvcsbdavw 36799. Deduction form. (Contributed by GG, 14-Aug-2025.)
⊢ (𝜑 → 𝐴 = 𝐵)    &   ⊢ ((𝜑 ∧ 𝑥 = 𝑦) → 𝐶 = 𝐷)    ⇒   ⊢ (𝜑 → ⦋𝐴 / 𝑥⦌𝐶 = ⦋𝐵 / 𝑦⦌𝐷)