P. 336 of Theorem List - Metamath Proof Explorer

Theorem List for Metamath Proof Explorer - 33501-33600   *Has distinct variable group(s)

Type	Label	Description
Statement
Theorem	ssmxidllem 33501*	The set 𝑃 used in the proof of ssmxidl 33502 satisfies the condition of Zorn's Lemma. (Contributed by Thierry Arnoux, 10-Apr-2024.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑃 = {𝑝 ∈ (LIdeal‘𝑅) ∣ (𝑝 ≠ 𝐵 ∧ 𝐼 ⊆ 𝑝)}    &   ⊢ (𝜑 → 𝑅 ∈ Ring)    &   ⊢ (𝜑 → 𝐼 ∈ (LIdeal‘𝑅))    &   ⊢ (𝜑 → 𝐼 ≠ 𝐵)    &   ⊢ (𝜑 → 𝑍 ⊆ 𝑃)    &   ⊢ (𝜑 → 𝑍 ≠ ∅)    &   ⊢ (𝜑 → [⊊] Or 𝑍)    ⇒   ⊢ (𝜑 → ∪ 𝑍 ∈ 𝑃)
Theorem	ssmxidl 33502*	Let 𝑅 be a ring, and let 𝐼 be a proper ideal of 𝑅. Then there is a maximal ideal of 𝑅 containing 𝐼. (Contributed by Thierry Arnoux, 10-Apr-2024.)
⊢ 𝐵 = (Base‘𝑅)    ⇒   ⊢ ((𝑅 ∈ Ring ∧ 𝐼 ∈ (LIdeal‘𝑅) ∧ 𝐼 ≠ 𝐵) → ∃𝑚 ∈ (MaxIdeal‘𝑅)𝐼 ⊆ 𝑚)
Theorem	drnglidl1ne0 33503	In a nonzero ring, the zero ideal is different of the unit ideal. (Contributed by Thierry Arnoux, 16-Mar-2025.)
⊢ 0 = (0g‘𝑅)    &   ⊢ 𝐵 = (Base‘𝑅)    ⇒   ⊢ (𝑅 ∈ NzRing → 𝐵 ≠ { 0 })
Theorem	drng0mxidl 33504	In a division ring, the zero ideal is a maximal ideal. (Contributed by Thierry Arnoux, 16-Mar-2025.)
⊢ 0 = (0g‘𝑅)    ⇒   ⊢ (𝑅 ∈ DivRing → { 0 } ∈ (MaxIdeal‘𝑅))
Theorem	drngmxidl 33505	The zero ideal is the only ideal of a division ring. (Contributed by Thierry Arnoux, 16-Mar-2025.)
⊢ 0 = (0g‘𝑅)    ⇒   ⊢ (𝑅 ∈ DivRing → (MaxIdeal‘𝑅) = {{ 0 }})
Theorem	drngmxidlr 33506	If a ring's only maximal ideal is the zero ideal, it is a division ring. See also drngmxidl 33505. (Contributed by Thierry Arnoux, 3-Jun-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    &   ⊢ 𝑀 = (MaxIdeal‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ NzRing)    &   ⊢ (𝜑 → 𝑀 = {{ 0 }})    ⇒   ⊢ (𝜑 → 𝑅 ∈ DivRing)
Theorem	krull 33507*	Krull's theorem: Any nonzero ring has at least one maximal ideal. (Contributed by Thierry Arnoux, 10-Apr-2024.)
⊢ (𝑅 ∈ NzRing → ∃𝑚 𝑚 ∈ (MaxIdeal‘𝑅))
Theorem	mxidlnzrb 33508*	A ring is nonzero if and only if it has maximal ideals. (Contributed by Thierry Arnoux, 10-Apr-2024.)
⊢ (𝑅 ∈ Ring → (𝑅 ∈ NzRing ↔ ∃𝑚 𝑚 ∈ (MaxIdeal‘𝑅)))
Theorem	krullndrng 33509*	Krull's theorem for non-division-rings: Existence of a nonzero maximal ideal. (Contributed by Thierry Arnoux, 3-Jun-2025.)
⊢ 0 = (0g‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ NzRing)    &   ⊢ (𝜑 → ¬ 𝑅 ∈ DivRing)    ⇒   ⊢ (𝜑 → ∃𝑚 ∈ (MaxIdeal‘𝑅)𝑚 ≠ { 0 })
Theorem	opprabs 33510	The opposite ring of the opposite ring is the original ring. Note the conditions on this theorem, which makes it unpractical in case we only have e.g. 𝑅 ∈ Ring as a premise. (Contributed by Thierry Arnoux, 9-Mar-2025.)
⊢ 𝑂 = (oppr‘𝑅)    &   ⊢ · = (.r‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ 𝑉)    &   ⊢ (𝜑 → Fun 𝑅)    &   ⊢ (𝜑 → (.r‘ndx) ∈ dom 𝑅)    &   ⊢ (𝜑 → · Fn (𝐵 × 𝐵))    ⇒   ⊢ (𝜑 → 𝑅 = (oppr‘𝑂))
Theorem	oppreqg 33511	Group coset equivalence relation for the opposite ring. (Contributed by Thierry Arnoux, 9-Mar-2025.)
⊢ 𝑂 = (oppr‘𝑅)    &   ⊢ 𝐵 = (Base‘𝑅)    ⇒   ⊢ ((𝑅 ∈ 𝑉 ∧ 𝐼 ⊆ 𝐵) → (𝑅 ~QG 𝐼) = (𝑂 ~QG 𝐼))
Theorem	opprnsg 33512	Normal subgroups of the opposite ring are the same as the original normal subgroups. (Contributed by Thierry Arnoux, 13-Mar-2025.)
⊢ 𝑂 = (oppr‘𝑅)    ⇒   ⊢ (NrmSGrp‘𝑅) = (NrmSGrp‘𝑂)
Theorem	opprlidlabs 33513	The ideals of the opposite ring's opposite ring are the ideals of the original ring. (Contributed by Thierry Arnoux, 9-Mar-2025.)
⊢ 𝑂 = (oppr‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ Ring)    ⇒   ⊢ (𝜑 → (LIdeal‘𝑅) = (LIdeal‘(oppr‘𝑂)))
Theorem	oppr2idl 33514	Two sided ideal of the opposite ring. (Contributed by Thierry Arnoux, 9-Mar-2025.)
⊢ 𝑂 = (oppr‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ Ring)    ⇒   ⊢ (𝜑 → (2Ideal‘𝑅) = (2Ideal‘𝑂))
Theorem	opprmxidlabs 33515	The maximal ideal of the opposite ring's opposite ring. (Contributed by Thierry Arnoux, 9-Mar-2025.)
⊢ 𝑂 = (oppr‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ Ring)    &   ⊢ (𝜑 → 𝑀 ∈ (MaxIdeal‘𝑅))    ⇒   ⊢ (𝜑 → 𝑀 ∈ (MaxIdeal‘(oppr‘𝑂)))
Theorem	opprqusbas 33516	The base of the quotient of the opposite ring is the same as the base of the opposite of the quotient ring. (Contributed by Thierry Arnoux, 9-Mar-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑂 = (oppr‘𝑅)    &   ⊢ 𝑄 = (𝑅 /s (𝑅 ~QG 𝐼))    &   ⊢ (𝜑 → 𝑅 ∈ 𝑉)    &   ⊢ (𝜑 → 𝐼 ⊆ 𝐵)    ⇒   ⊢ (𝜑 → (Base‘(oppr‘𝑄)) = (Base‘(𝑂 /s (𝑂 ~QG 𝐼))))
Theorem	opprqusplusg 33517	The group operation of the quotient of the opposite ring is the same as the group operation of the opposite of the quotient ring. (Contributed by Thierry Arnoux, 13-Mar-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑂 = (oppr‘𝑅)    &   ⊢ 𝑄 = (𝑅 /s (𝑅 ~QG 𝐼))    &   ⊢ (𝜑 → 𝐼 ∈ (NrmSGrp‘𝑅))    &   ⊢ 𝐸 = (Base‘𝑄)    &   ⊢ (𝜑 → 𝑋 ∈ 𝐸)    &   ⊢ (𝜑 → 𝑌 ∈ 𝐸)    ⇒   ⊢ (𝜑 → (𝑋(+g‘(oppr‘𝑄))𝑌) = (𝑋(+g‘(𝑂 /s (𝑂 ~QG 𝐼)))𝑌))
Theorem	opprqus0g 33518	The group identity element of the quotient of the opposite ring is the same as the group identity element of the opposite of the quotient ring. (Contributed by Thierry Arnoux, 13-Mar-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑂 = (oppr‘𝑅)    &   ⊢ 𝑄 = (𝑅 /s (𝑅 ~QG 𝐼))    &   ⊢ (𝜑 → 𝐼 ∈ (NrmSGrp‘𝑅))    ⇒   ⊢ (𝜑 → (0g‘(oppr‘𝑄)) = (0g‘(𝑂 /s (𝑂 ~QG 𝐼))))
Theorem	opprqusmulr 33519	The multiplication operation of the quotient of the opposite ring is the same as the multiplication operation of the opposite of the quotient ring. (Contributed by Thierry Arnoux, 9-Mar-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑂 = (oppr‘𝑅)    &   ⊢ 𝑄 = (𝑅 /s (𝑅 ~QG 𝐼))    &   ⊢ (𝜑 → 𝑅 ∈ Ring)    &   ⊢ (𝜑 → 𝐼 ∈ (2Ideal‘𝑅))    &   ⊢ 𝐸 = (Base‘𝑄)    &   ⊢ (𝜑 → 𝑋 ∈ 𝐸)    &   ⊢ (𝜑 → 𝑌 ∈ 𝐸)    ⇒   ⊢ (𝜑 → (𝑋(.r‘(oppr‘𝑄))𝑌) = (𝑋(.r‘(𝑂 /s (𝑂 ~QG 𝐼)))𝑌))
Theorem	opprqus1r 33520	The ring unity of the quotient of the opposite ring is the same as the ring unity of the opposite of the quotient ring. (Contributed by Thierry Arnoux, 9-Mar-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑂 = (oppr‘𝑅)    &   ⊢ 𝑄 = (𝑅 /s (𝑅 ~QG 𝐼))    &   ⊢ (𝜑 → 𝑅 ∈ Ring)    &   ⊢ (𝜑 → 𝐼 ∈ (2Ideal‘𝑅))    ⇒   ⊢ (𝜑 → (1r‘(oppr‘𝑄)) = (1r‘(𝑂 /s (𝑂 ~QG 𝐼))))
Theorem	opprqusdrng 33521	The quotient of the opposite ring is a division ring iff the opposite of the quotient ring is. (Contributed by Thierry Arnoux, 13-Mar-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑂 = (oppr‘𝑅)    &   ⊢ 𝑄 = (𝑅 /s (𝑅 ~QG 𝐼))    &   ⊢ (𝜑 → 𝑅 ∈ Ring)    &   ⊢ (𝜑 → 𝐼 ∈ (2Ideal‘𝑅))    ⇒   ⊢ (𝜑 → ((oppr‘𝑄) ∈ DivRing ↔ (𝑂 /s (𝑂 ~QG 𝐼)) ∈ DivRing))
Theorem	qsdrngilem 33522*	Lemma for qsdrngi 33523. (Contributed by Thierry Arnoux, 9-Mar-2025.)
⊢ 𝑂 = (oppr‘𝑅)    &   ⊢ 𝑄 = (𝑅 /s (𝑅 ~QG 𝑀))    &   ⊢ (𝜑 → 𝑅 ∈ NzRing)    &   ⊢ (𝜑 → 𝑀 ∈ (MaxIdeal‘𝑅))    &   ⊢ (𝜑 → 𝑀 ∈ (MaxIdeal‘𝑂))    &   ⊢ (𝜑 → 𝑋 ∈ (Base‘𝑅))    &   ⊢ (𝜑 → ¬ 𝑋 ∈ 𝑀)    ⇒   ⊢ (𝜑 → ∃𝑣 ∈ (Base‘𝑄)(𝑣(.r‘𝑄)[𝑋](𝑅 ~QG 𝑀)) = (1r‘𝑄))
Theorem	qsdrngi 33523	A quotient by a maximal left and maximal right ideal is a division ring. (Contributed by Thierry Arnoux, 9-Mar-2025.)
⊢ 𝑂 = (oppr‘𝑅)    &   ⊢ 𝑄 = (𝑅 /s (𝑅 ~QG 𝑀))    &   ⊢ (𝜑 → 𝑅 ∈ NzRing)    &   ⊢ (𝜑 → 𝑀 ∈ (MaxIdeal‘𝑅))    &   ⊢ (𝜑 → 𝑀 ∈ (MaxIdeal‘𝑂))    ⇒   ⊢ (𝜑 → 𝑄 ∈ DivRing)
Theorem	qsdrnglem2 33524	Lemma for qsdrng 33525. (Contributed by Thierry Arnoux, 13-Mar-2025.)
⊢ 𝑂 = (oppr‘𝑅)    &   ⊢ 𝑄 = (𝑅 /s (𝑅 ~QG 𝑀))    &   ⊢ (𝜑 → 𝑅 ∈ NzRing)    &   ⊢ (𝜑 → 𝑀 ∈ (2Ideal‘𝑅))    &   ⊢ 𝐵 = (Base‘𝑅)    &   ⊢ (𝜑 → 𝑄 ∈ DivRing)    &   ⊢ (𝜑 → 𝐽 ∈ (LIdeal‘𝑅))    &   ⊢ (𝜑 → 𝑀 ⊆ 𝐽)    &   ⊢ (𝜑 → 𝑋 ∈ (𝐽 ∖ 𝑀))    ⇒   ⊢ (𝜑 → 𝐽 = 𝐵)
Theorem	qsdrng 33525	An ideal 𝑀 is both left and right maximal if and only if the factor ring 𝑄 is a division ring. (Contributed by Thierry Arnoux, 13-Mar-2025.)
⊢ 𝑂 = (oppr‘𝑅)    &   ⊢ 𝑄 = (𝑅 /s (𝑅 ~QG 𝑀))    &   ⊢ (𝜑 → 𝑅 ∈ NzRing)    &   ⊢ (𝜑 → 𝑀 ∈ (2Ideal‘𝑅))    ⇒   ⊢ (𝜑 → (𝑄 ∈ DivRing ↔ (𝑀 ∈ (MaxIdeal‘𝑅) ∧ 𝑀 ∈ (MaxIdeal‘𝑂))))
Theorem	qsfld 33526	An ideal 𝑀 in the commutative ring 𝑅 is maximal if and only if the factor ring 𝑄 is a field. (Contributed by Thierry Arnoux, 13-Mar-2025.)
⊢ 𝑄 = (𝑅 /s (𝑅 ~QG 𝑀))    &   ⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ (𝜑 → 𝑅 ∈ NzRing)    &   ⊢ (𝜑 → 𝑀 ∈ (LIdeal‘𝑅))    ⇒   ⊢ (𝜑 → (𝑄 ∈ Field ↔ 𝑀 ∈ (MaxIdeal‘𝑅)))
Theorem	mxidlprmALT 33527	Every maximal ideal is prime - alternative proof. (Contributed by Thierry Arnoux, 15-Mar-2025.) (Proof modification is discouraged.) (New usage is discouraged.)
⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ (𝜑 → 𝑀 ∈ (MaxIdeal‘𝑅))    ⇒   ⊢ (𝜑 → 𝑀 ∈ (PrmIdeal‘𝑅))
21.3.10.42  The semiring of ideals of a ring
Syntax	cidlsrg 33528	Extend class notation with the semiring of ideals of a ring.
class IDLsrg
Definition	df-idlsrg 33529*	Define a structure for the ideals of a ring. (Contributed by Thierry Arnoux, 21-Jan-2024.)
⊢ IDLsrg = (𝑟 ∈ V ↦ ⦋(LIdeal‘𝑟) / 𝑏⦌({⟨(Base‘ndx), 𝑏⟩, ⟨(+g‘ndx), (LSSum‘𝑟)⟩, ⟨(.r‘ndx), (𝑖 ∈ 𝑏, 𝑗 ∈ 𝑏 ↦ ((RSpan‘𝑟)‘(𝑖(LSSum‘(mulGrp‘𝑟))𝑗)))⟩} ∪ {⟨(TopSet‘ndx), ran (𝑖 ∈ 𝑏 ↦ {𝑗 ∈ 𝑏 ∣ ¬ 𝑖 ⊆ 𝑗})⟩, ⟨(le‘ndx), {⟨𝑖, 𝑗⟩ ∣ ({𝑖, 𝑗} ⊆ 𝑏 ∧ 𝑖 ⊆ 𝑗)}⟩}))
Theorem	idlsrgstr 33530	A constructed semiring of ideals is a structure. (Contributed by Thierry Arnoux, 1-Jun-2024.)
⊢ 𝑊 = ({⟨(Base‘ndx), 𝐵⟩, ⟨(+g‘ndx), + ⟩, ⟨(.r‘ndx), · ⟩} ∪ {⟨(TopSet‘ndx), 𝐽⟩, ⟨(le‘ndx), ≤ ⟩})    ⇒   ⊢ 𝑊 Struct ⟨1, ;10⟩
Theorem	idlsrgval 33531*	Lemma for idlsrgbas 33532 through idlsrgtset 33536. (Contributed by Thierry Arnoux, 1-Jun-2024.)
⊢ 𝐼 = (LIdeal‘𝑅)    &   ⊢ ⊕ = (LSSum‘𝑅)    &   ⊢ 𝐺 = (mulGrp‘𝑅)    &   ⊢ ⊗ = (LSSum‘𝐺)    ⇒   ⊢ (𝑅 ∈ 𝑉 → (IDLsrg‘𝑅) = ({⟨(Base‘ndx), 𝐼⟩, ⟨(+g‘ndx), ⊕ ⟩, ⟨(.r‘ndx), (𝑖 ∈ 𝐼, 𝑗 ∈ 𝐼 ↦ ((RSpan‘𝑅)‘(𝑖 ⊗ 𝑗)))⟩} ∪ {⟨(TopSet‘ndx), ran (𝑖 ∈ 𝐼 ↦ {𝑗 ∈ 𝐼 ∣ ¬ 𝑖 ⊆ 𝑗})⟩, ⟨(le‘ndx), {⟨𝑖, 𝑗⟩ ∣ ({𝑖, 𝑗} ⊆ 𝐼 ∧ 𝑖 ⊆ 𝑗)}⟩}))
Theorem	idlsrgbas 33532	Base of the ideals of a ring. (Contributed by Thierry Arnoux, 1-Jun-2024.)
⊢ 𝑆 = (IDLsrg‘𝑅)    &   ⊢ 𝐼 = (LIdeal‘𝑅)    ⇒   ⊢ (𝑅 ∈ 𝑉 → 𝐼 = (Base‘𝑆))
Theorem	idlsrgplusg 33533	Additive operation of the ideals of a ring. (Contributed by Thierry Arnoux, 1-Jun-2024.)
⊢ 𝑆 = (IDLsrg‘𝑅)    &   ⊢ ⊕ = (LSSum‘𝑅)    ⇒   ⊢ (𝑅 ∈ 𝑉 → ⊕ = (+g‘𝑆))
Theorem	idlsrg0g 33534	The zero ideal is the additive identity of the semiring of ideals. (Contributed by Thierry Arnoux, 1-Jun-2024.)
⊢ 𝑆 = (IDLsrg‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    ⇒   ⊢ (𝑅 ∈ Ring → { 0 } = (0g‘𝑆))
Theorem	idlsrgmulr 33535*	Multiplicative operation of the ideals of a ring. (Contributed by Thierry Arnoux, 1-Jun-2024.)
⊢ 𝑆 = (IDLsrg‘𝑅)    &   ⊢ 𝐵 = (LIdeal‘𝑅)    &   ⊢ 𝐺 = (mulGrp‘𝑅)    &   ⊢ ⊗ = (LSSum‘𝐺)    ⇒   ⊢ (𝑅 ∈ 𝑉 → (𝑖 ∈ 𝐵, 𝑗 ∈ 𝐵 ↦ ((RSpan‘𝑅)‘(𝑖 ⊗ 𝑗))) = (.r‘𝑆))
Theorem	idlsrgtset 33536*	Topology component of the ideals of a ring. (Contributed by Thierry Arnoux, 1-Jun-2024.)
⊢ 𝑆 = (IDLsrg‘𝑅)    &   ⊢ 𝐼 = (LIdeal‘𝑅)    &   ⊢ 𝐽 = ran (𝑖 ∈ 𝐼 ↦ {𝑗 ∈ 𝐼 ∣ ¬ 𝑖 ⊆ 𝑗})    ⇒   ⊢ (𝑅 ∈ 𝑉 → 𝐽 = (TopSet‘𝑆))
Theorem	idlsrgmulrval 33537	Value of the ring multiplication for the ideals of a ring 𝑅. (Contributed by Thierry Arnoux, 1-Jun-2024.)
⊢ 𝑆 = (IDLsrg‘𝑅)    &   ⊢ 𝐵 = (LIdeal‘𝑅)    &   ⊢ ⊗ = (.r‘𝑆)    &   ⊢ 𝐺 = (mulGrp‘𝑅)    &   ⊢ · = (LSSum‘𝐺)    &   ⊢ (𝜑 → 𝑅 ∈ 𝑉)    &   ⊢ (𝜑 → 𝐼 ∈ 𝐵)    &   ⊢ (𝜑 → 𝐽 ∈ 𝐵)    ⇒   ⊢ (𝜑 → (𝐼 ⊗ 𝐽) = ((RSpan‘𝑅)‘(𝐼 · 𝐽)))
Theorem	idlsrgmulrcl 33538	Ideals of a ring 𝑅 are closed under multiplication. (Contributed by Thierry Arnoux, 1-Jun-2024.)
⊢ 𝑆 = (IDLsrg‘𝑅)    &   ⊢ 𝐵 = (LIdeal‘𝑅)    &   ⊢ ⊗ = (.r‘𝑆)    &   ⊢ (𝜑 → 𝑅 ∈ Ring)    &   ⊢ (𝜑 → 𝐼 ∈ 𝐵)    &   ⊢ (𝜑 → 𝐽 ∈ 𝐵)    ⇒   ⊢ (𝜑 → (𝐼 ⊗ 𝐽) ∈ 𝐵)
Theorem	idlsrgmulrss1 33539	In a commutative ring, the product of two ideals is a subset of the first one. (Contributed by Thierry Arnoux, 16-Jun-2024.)
⊢ 𝑆 = (IDLsrg‘𝑅)    &   ⊢ 𝐵 = (LIdeal‘𝑅)    &   ⊢ ⊗ = (.r‘𝑆)    &   ⊢ · = (.r‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ (𝜑 → 𝐼 ∈ 𝐵)    &   ⊢ (𝜑 → 𝐽 ∈ 𝐵)    ⇒   ⊢ (𝜑 → (𝐼 ⊗ 𝐽) ⊆ 𝐼)
Theorem	idlsrgmulrss2 33540	The product of two ideals is a subset of the second one. (Contributed by Thierry Arnoux, 2-Jun-2024.)
⊢ 𝑆 = (IDLsrg‘𝑅)    &   ⊢ 𝐵 = (LIdeal‘𝑅)    &   ⊢ ⊗ = (.r‘𝑆)    &   ⊢ · = (.r‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ Ring)    &   ⊢ (𝜑 → 𝐼 ∈ 𝐵)    &   ⊢ (𝜑 → 𝐽 ∈ 𝐵)    ⇒   ⊢ (𝜑 → (𝐼 ⊗ 𝐽) ⊆ 𝐽)
Theorem	idlsrgmulrssin 33541	In a commutative ring, the product of two ideals is a subset of their intersection. (Contributed by Thierry Arnoux, 17-Jun-2024.)
⊢ 𝑆 = (IDLsrg‘𝑅)    &   ⊢ 𝐵 = (LIdeal‘𝑅)    &   ⊢ ⊗ = (.r‘𝑆)    &   ⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ (𝜑 → 𝐼 ∈ 𝐵)    &   ⊢ (𝜑 → 𝐽 ∈ 𝐵)    ⇒   ⊢ (𝜑 → (𝐼 ⊗ 𝐽) ⊆ (𝐼 ∩ 𝐽))
Theorem	idlsrgmnd 33542	The ideals of a ring form a monoid. (Contributed by Thierry Arnoux, 1-Jun-2024.)
⊢ 𝑆 = (IDLsrg‘𝑅)    ⇒   ⊢ (𝑅 ∈ Ring → 𝑆 ∈ Mnd)
Theorem	idlsrgcmnd 33543	The ideals of a ring form a commutative monoid. (Contributed by Thierry Arnoux, 1-Jun-2024.)
⊢ 𝑆 = (IDLsrg‘𝑅)    ⇒   ⊢ (𝑅 ∈ Ring → 𝑆 ∈ CMnd)
21.3.10.43  Prime Elements
Theorem	rprmval 33544*	The prime elements of a ring 𝑅. (Contributed by Thierry Arnoux, 1-Jul-2024.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑈 = (Unit‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    &   ⊢ · = (.r‘𝑅)    &   ⊢ ∥ = (∥r‘𝑅)    ⇒   ⊢ (𝑅 ∈ 𝑉 → (RPrime‘𝑅) = {𝑝 ∈ (𝐵 ∖ (𝑈 ∪ { 0 })) ∣ ∀𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 (𝑝 ∥ (𝑥 · 𝑦) → (𝑝 ∥ 𝑥 ∨ 𝑝 ∥ 𝑦))})
Theorem	isrprm 33545*	Property for 𝑃 to be a prime element in the ring 𝑅. (Contributed by Thierry Arnoux, 1-Jul-2024.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑈 = (Unit‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    &   ⊢ ∥ = (∥r‘𝑅)    &   ⊢ · = (.r‘𝑅)    ⇒   ⊢ (𝑅 ∈ 𝑉 → (𝑃 ∈ (RPrime‘𝑅) ↔ (𝑃 ∈ (𝐵 ∖ (𝑈 ∪ { 0 })) ∧ ∀𝑥 ∈ 𝐵 ∀𝑦 ∈ 𝐵 (𝑃 ∥ (𝑥 · 𝑦) → (𝑃 ∥ 𝑥 ∨ 𝑃 ∥ 𝑦)))))
Theorem	rprmcl 33546	A ring prime is an element of the base set. (Contributed by Thierry Arnoux, 18-May-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ 𝑉)    &   ⊢ (𝜑 → 𝑋 ∈ 𝑃)    ⇒   ⊢ (𝜑 → 𝑋 ∈ 𝐵)
Theorem	rprmdvds 33547	If a ring prime 𝑄 divides a product 𝑋 · 𝑌, then it divides either 𝑋 or 𝑌. (Contributed by Thierry Arnoux, 18-May-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ ∥ = (∥r‘𝑅)    &   ⊢ · = (.r‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ 𝑉)    &   ⊢ (𝜑 → 𝑄 ∈ 𝑃)    &   ⊢ (𝜑 → 𝑋 ∈ 𝐵)    &   ⊢ (𝜑 → 𝑌 ∈ 𝐵)    &   ⊢ (𝜑 → 𝑄 ∥ (𝑋 · 𝑌))    ⇒   ⊢ (𝜑 → (𝑄 ∥ 𝑋 ∨ 𝑄 ∥ 𝑌))
Theorem	rprmnz 33548	A ring prime is nonzero. (Contributed by Thierry Arnoux, 18-May-2025.)
⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ 𝑉)    &   ⊢ (𝜑 → 𝑄 ∈ 𝑃)    ⇒   ⊢ (𝜑 → 𝑄 ≠ 0 )
Theorem	rprmnunit 33549	A ring prime is not a unit. (Contributed by Thierry Arnoux, 18-May-2025.)
⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 𝑈 = (Unit‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ 𝑉)    &   ⊢ (𝜑 → 𝑄 ∈ 𝑃)    ⇒   ⊢ (𝜑 → ¬ 𝑄 ∈ 𝑈)
Theorem	rsprprmprmidl 33550	In a commutative ring, ideals generated by prime elements are prime ideals. (Contributed by Thierry Arnoux, 18-May-2025.)
⊢ 𝐾 = (RSpan‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ (𝜑 → 𝑃 ∈ (RPrime‘𝑅))    ⇒   ⊢ (𝜑 → (𝐾‘{𝑃}) ∈ (PrmIdeal‘𝑅))
Theorem	rsprprmprmidlb 33551	In an integral domain, an ideal generated by a single element is a prime iff that element is prime. (Contributed by Thierry Arnoux, 18-May-2025.)
⊢ 0 = (0g‘𝑅)    &   ⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 𝐾 = (RSpan‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ IDomn)    &   ⊢ (𝜑 → 𝑋 ∈ 𝐵)    &   ⊢ (𝜑 → 𝑋 ≠ 0 )    ⇒   ⊢ (𝜑 → (𝑋 ∈ 𝑃 ↔ (𝐾‘{𝑋}) ∈ (PrmIdeal‘𝑅)))
Theorem	rprmndvdsr1 33552	A ring prime element does not divide the ring multiplicative identity. (Contributed by Thierry Arnoux, 18-May-2025.)
⊢ 1 = (1r‘𝑅)    &   ⊢ ∥ = (∥r‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ (𝜑 → 𝑄 ∈ 𝑃)    ⇒   ⊢ (𝜑 → ¬ 𝑄 ∥ 1 )
Theorem	rprmasso 33553	In an integral domain, the associate of a prime is a prime. (Contributed by Thierry Arnoux, 18-May-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ ∥ = (∥r‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ IDomn)    &   ⊢ (𝜑 → 𝑋 ∈ 𝑃)    &   ⊢ (𝜑 → 𝑋 ∥ 𝑌)    &   ⊢ (𝜑 → 𝑌 ∥ 𝑋)    ⇒   ⊢ (𝜑 → 𝑌 ∈ 𝑃)
Theorem	rprmasso2 33554	In an integral domain, if a prime element divides another, they are associates. (Contributed by Thierry Arnoux, 18-May-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ ∥ = (∥r‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ IDomn)    &   ⊢ (𝜑 → 𝑋 ∈ 𝑃)    &   ⊢ (𝜑 → 𝑋 ∥ 𝑌)    &   ⊢ (𝜑 → 𝑌 ∈ 𝑃)    ⇒   ⊢ (𝜑 → 𝑌 ∥ 𝑋)
Theorem	rprmasso3 33555*	In an integral domain, if a prime element divides another, they are associates. (Contributed by Thierry Arnoux, 27-May-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ ∥ = (∥r‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ IDomn)    &   ⊢ (𝜑 → 𝑋 ∈ 𝑃)    &   ⊢ (𝜑 → 𝑋 ∥ 𝑌)    &   ⊢ (𝜑 → 𝑌 ∈ 𝑃)    &   ⊢ · = (.r‘𝑅)    &   ⊢ 𝑈 = (Unit‘𝑅)    ⇒   ⊢ (𝜑 → ∃𝑡 ∈ 𝑈 (𝑡 · 𝑋) = 𝑌)
Theorem	unitmulrprm 33556	A ring unit multiplied by a ring prime is a ring prime. (Contributed by Thierry Arnoux, 3-Jun-2025.)
⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 𝑈 = (Unit‘𝑅)    &   ⊢ · = (.r‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ IDomn)    &   ⊢ (𝜑 → 𝐼 ∈ 𝑈)    &   ⊢ (𝜑 → 𝑄 ∈ 𝑃)    ⇒   ⊢ (𝜑 → (𝐼 · 𝑄) ∈ 𝑃)
Theorem	rprmndvdsru 33557	A ring prime element does not divide any ring unit. (Contributed by Thierry Arnoux, 27-May-2025.)
⊢ 𝑈 = (Unit‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ ∥ = (∥r‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ (𝜑 → 𝑄 ∈ 𝑃)    &   ⊢ (𝜑 → 𝑇 ∈ 𝑈)    ⇒   ⊢ (𝜑 → ¬ 𝑄 ∥ 𝑇)
Theorem	rprmirredlem 33558	Lemma for rprmirred 33559. (Contributed by Thierry Arnoux, 18-May-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑈 = (Unit‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    &   ⊢ · = (.r‘𝑅)    &   ⊢ ∥ = (∥r‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ IDomn)    &   ⊢ (𝜑 → 𝑄 ≠ 0 )    &   ⊢ (𝜑 → 𝑋 ∈ (𝐵 ∖ 𝑈))    &   ⊢ (𝜑 → 𝑌 ∈ 𝐵)    &   ⊢ (𝜑 → 𝑄 = (𝑋 · 𝑌))    &   ⊢ (𝜑 → 𝑄 ∥ 𝑋)    ⇒   ⊢ (𝜑 → 𝑌 ∈ 𝑈)
Theorem	rprmirred 33559	In an integral domain, ring primes are irreducible. (Contributed by Thierry Arnoux, 18-May-2025.)
⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 𝐼 = (Irred‘𝑅)    &   ⊢ (𝜑 → 𝑄 ∈ 𝑃)    &   ⊢ (𝜑 → 𝑅 ∈ IDomn)    ⇒   ⊢ (𝜑 → 𝑄 ∈ 𝐼)
Theorem	rprmirredb 33560	In a principal ideal domain, the converse of rprmirred 33559 holds, i.e. irreducible elements are prime. (Contributed by Thierry Arnoux, 18-May-2025.)
⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 𝐼 = (Irred‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ PID)    ⇒   ⊢ (𝜑 → 𝐼 = 𝑃)
Theorem	rprmdvdspow 33561	If a prime element divides a ring "power", it divides the term. (Contributed by Thierry Arnoux, 18-May-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ ∥ = (∥r‘𝑅)    &   ⊢ 𝑀 = (mulGrp‘𝑅)    &   ⊢ ↑ = (.g‘𝑀)    &   ⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ (𝜑 → 𝑋 ∈ 𝐵)    &   ⊢ (𝜑 → 𝑄 ∈ 𝑃)    &   ⊢ (𝜑 → 𝑁 ∈ ℕ0)    &   ⊢ (𝜑 → 𝑄 ∥ (𝑁 ↑ 𝑋))    ⇒   ⊢ (𝜑 → 𝑄 ∥ 𝑋)
Theorem	rprmdvdsprod 33562*	If a prime element 𝑄 divides a product, then it divides one term. (Contributed by Thierry Arnoux, 18-May-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ ∥ = (∥r‘𝑅)    &   ⊢ 1 = (1r‘𝑅)    &   ⊢ 𝑀 = (mulGrp‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ (𝜑 → 𝑄 ∈ 𝑃)    &   ⊢ (𝜑 → 𝐼 ∈ 𝑉)    &   ⊢ (𝜑 → 𝐹 finSupp 1 )    &   ⊢ (𝜑 → 𝐹:𝐼⟶𝐵)    &   ⊢ (𝜑 → 𝑄 ∥ (𝑀 Σg 𝐹))    ⇒   ⊢ (𝜑 → ∃𝑥 ∈ (𝐹 supp 1 )𝑄 ∥ (𝐹‘𝑥))
Theorem	1arithidomlem1 33563*	Lemma for 1arithidom 33565. (Contributed by Thierry Arnoux, 30-May-2025.)
⊢ 𝑈 = (Unit‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 𝑀 = (mulGrp‘𝑅)    &   ⊢ · = (.r‘𝑅)    &   ⊢ 𝐽 = (0..^(♯‘𝐹))    &   ⊢ (𝜑 → 𝑅 ∈ IDomn)    &   ⊢ (𝜑 → 𝐹 ∈ Word 𝑃)    &   ⊢ (𝜑 → 𝐺 ∈ Word 𝑃)    &   ⊢ (𝜑 → (𝑀 Σg 𝐹) = (𝑀 Σg 𝐺))    &   ⊢ (𝜑 → 𝑄 ∈ 𝑃)    &   ⊢ (𝜑 → ∀𝑔 ∈ Word 𝑃(∃𝑘 ∈ 𝑈 (𝑀 Σg 𝐹) = (𝑘 · (𝑀 Σg 𝑔)) → ∃𝑤∃𝑢 ∈ (𝑈 ↑m (0..^(♯‘𝐹)))(𝑤:(0..^(♯‘𝐹))–1-1-onto→(0..^(♯‘𝐹)) ∧ 𝑔 = (𝑢 ∘f · (𝐹 ∘ 𝑤)))))    &   ⊢ (𝜑 → 𝐻 ∈ Word 𝑃)    &   ⊢ (𝜑 → ∃𝑘 ∈ 𝑈 (𝑀 Σg (𝐹 ++ ⟨“𝑄”⟩)) = (𝑘 · (𝑀 Σg 𝐻)))    &   ⊢ (𝜑 → 𝐾 ∈ (0..^(♯‘𝐻)))    &   ⊢ (𝜑 → 𝑄(∥r‘𝑅)(𝐻‘𝐾))    &   ⊢ (𝜑 → 𝑇 ∈ 𝑈)    &   ⊢ (𝜑 → (𝑇 · 𝑄) = (𝐻‘𝐾))    &   ⊢ (𝜑 → 𝑆:(0..^(♯‘𝐻))–1-1-onto→(0..^(♯‘𝐻)))    &   ⊢ (𝜑 → (𝐻 ∘ 𝑆) = (((𝐻 ∘ 𝑆) prefix ((♯‘𝐻) − 1)) ++ ⟨“(𝐻‘𝐾)”⟩))    &   ⊢ (𝜑 → 𝑁 ∈ 𝑈)    &   ⊢ (𝜑 → (𝑀 Σg (𝐹 ++ ⟨“𝑄”⟩)) = (𝑁 · (𝑀 Σg 𝐻)))    ⇒   ⊢ (𝜑 → ∃𝑐∃𝑑 ∈ (𝑈 ↑m (0..^(♯‘𝐹)))(𝑐:(0..^(♯‘𝐹))–1-1-onto→(0..^(♯‘𝐹)) ∧ ((𝐻 ∘ 𝑆) prefix ((♯‘𝐻) − 1)) = (𝑑 ∘f · (𝐹 ∘ 𝑐))))
Theorem	1arithidomlem2 33564*	Lemma for 1arithidom 33565: induction step. (Contributed by Thierry Arnoux, 27-May-2025.)
⊢ 𝑈 = (Unit‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 𝑀 = (mulGrp‘𝑅)    &   ⊢ · = (.r‘𝑅)    &   ⊢ 𝐽 = (0..^(♯‘𝐹))    &   ⊢ (𝜑 → 𝑅 ∈ IDomn)    &   ⊢ (𝜑 → 𝐹 ∈ Word 𝑃)    &   ⊢ (𝜑 → 𝐺 ∈ Word 𝑃)    &   ⊢ (𝜑 → (𝑀 Σg 𝐹) = (𝑀 Σg 𝐺))    &   ⊢ (𝜑 → 𝑄 ∈ 𝑃)    &   ⊢ (𝜑 → ∀𝑔 ∈ Word 𝑃(∃𝑘 ∈ 𝑈 (𝑀 Σg 𝐹) = (𝑘 · (𝑀 Σg 𝑔)) → ∃𝑤∃𝑢 ∈ (𝑈 ↑m (0..^(♯‘𝐹)))(𝑤:(0..^(♯‘𝐹))–1-1-onto→(0..^(♯‘𝐹)) ∧ 𝑔 = (𝑢 ∘f · (𝐹 ∘ 𝑤)))))    &   ⊢ (𝜑 → 𝐻 ∈ Word 𝑃)    &   ⊢ (𝜑 → ∃𝑘 ∈ 𝑈 (𝑀 Σg (𝐹 ++ ⟨“𝑄”⟩)) = (𝑘 · (𝑀 Σg 𝐻)))    &   ⊢ (𝜑 → 𝐾 ∈ (0..^(♯‘𝐻)))    &   ⊢ (𝜑 → 𝑄(∥r‘𝑅)(𝐻‘𝐾))    &   ⊢ (𝜑 → 𝑇 ∈ 𝑈)    &   ⊢ (𝜑 → (𝑇 · 𝑄) = (𝐻‘𝐾))    &   ⊢ (𝜑 → 𝑆:(0..^(♯‘𝐻))–1-1-onto→(0..^(♯‘𝐻)))    &   ⊢ (𝜑 → (𝐻 ∘ 𝑆) = (((𝐻 ∘ 𝑆) prefix ((♯‘𝐻) − 1)) ++ ⟨“(𝐻‘𝐾)”⟩))    &   ⊢ (𝜑 → 𝑁 ∈ 𝑈)    &   ⊢ (𝜑 → (𝑀 Σg (𝐹 ++ ⟨“𝑄”⟩)) = (𝑁 · (𝑀 Σg 𝐻)))    &   ⊢ (𝜑 → 𝐷 ∈ (𝑈 ↑m (0..^(♯‘𝐹))))    &   ⊢ (𝜑 → 𝐶:(0..^(♯‘𝐹))–1-1-onto→(0..^(♯‘𝐹)))    &   ⊢ (𝜑 → ((𝐻 ∘ 𝑆) prefix ((♯‘𝐻) − 1)) = (𝐷 ∘f · (𝐹 ∘ 𝐶)))    ⇒   ⊢ (𝜑 → (((𝐶 ++ ⟨“(♯‘𝐹)”⟩) ∘ ◡𝑆):(0..^(♯‘(𝐹 ++ ⟨“𝑄”⟩)))–1-1-onto→(0..^(♯‘(𝐹 ++ ⟨“𝑄”⟩))) ∧ 𝐻 = (((𝐷 ++ ⟨“𝑇”⟩) ∘ ◡𝑆) ∘f · ((𝐹 ++ ⟨“𝑄”⟩) ∘ ((𝐶 ++ ⟨“(♯‘𝐹)”⟩) ∘ ◡𝑆)))))
Theorem	1arithidom 33565*	Uniqueness of prime factorizations in an integral domain 𝑅. Given two equal products 𝐹 and 𝐺 of prime elements, 𝐹 and 𝐺 are equal up to a renumbering 𝑤 and a multiplication by units 𝑢. See also 1arith 16965. Chapter VII, Paragraph 3, Section 3, Proposition 2 of [BourbakiCAlg2], p. 228. (Contributed by Thierry Arnoux, 27-May-2025.)
⊢ 𝑈 = (Unit‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 𝑀 = (mulGrp‘𝑅)    &   ⊢ · = (.r‘𝑅)    &   ⊢ 𝐽 = (0..^(♯‘𝐹))    &   ⊢ (𝜑 → 𝑅 ∈ IDomn)    &   ⊢ (𝜑 → 𝐹 ∈ Word 𝑃)    &   ⊢ (𝜑 → 𝐺 ∈ Word 𝑃)    &   ⊢ (𝜑 → (𝑀 Σg 𝐹) = (𝑀 Σg 𝐺))    ⇒   ⊢ (𝜑 → ∃𝑤∃𝑢 ∈ (𝑈 ↑m 𝐽)(𝑤:𝐽–1-1-onto→𝐽 ∧ 𝐺 = (𝑢 ∘f · (𝐹 ∘ 𝑤))))
21.3.10.44  Unique factorization domains
Syntax	cufd 33566	Class of unique factorization domains.
class UFD
Definition	df-ufd 33567*	Define the class of unique factorization domains. A unique factorization domain (UFD for short), is an integral domain such that every nonzero prime ideal contains a prime element (this is a characterization due to Irving Kaplansky). A UFD is sometimes also called a "factorial ring" following the terminology of Bourbaki. (Contributed by Mario Carneiro, 17-Feb-2015.) Exclude the 0 prime ideal. (Revised by Thierry Arnoux, 9-May-2025.) Exclude the 0 ring. (Revised by Thierry Arnoux, 14-Jun-2025.)
⊢ UFD = {𝑟 ∈ IDomn ∣ ∀𝑖 ∈ ((PrmIdeal‘𝑟) ∖ {{(0g‘𝑟)}})(𝑖 ∩ (RPrime‘𝑟)) ≠ ∅}
Theorem	isufd 33568*	The property of being a Unique Factorization Domain. (Contributed by Thierry Arnoux, 1-Jun-2024.)
⊢ 𝐼 = (PrmIdeal‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    ⇒   ⊢ (𝑅 ∈ UFD ↔ (𝑅 ∈ IDomn ∧ ∀𝑖 ∈ (𝐼 ∖ {{ 0 }})(𝑖 ∩ 𝑃) ≠ ∅))
Theorem	ufdprmidl 33569*	In a unique factorization domain 𝑅, a nonzero prime ideal 𝐽 contains a prime element 𝑝. (Contributed by Thierry Arnoux, 3-Jun-2025.)
⊢ 𝐼 = (PrmIdeal‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ UFD)    &   ⊢ (𝜑 → 𝐽 ∈ 𝐼)    &   ⊢ (𝜑 → 𝐽 ≠ { 0 })    ⇒   ⊢ (𝜑 → ∃𝑝 ∈ 𝑃 𝑝 ∈ 𝐽)
Theorem	ufdidom 33570	A nonzero unique factorization domain is an integral domain. (Contributed by Thierry Arnoux, 3-Jun-2025.)
⊢ (𝜑 → 𝑅 ∈ UFD)    ⇒   ⊢ (𝜑 → 𝑅 ∈ IDomn)
Theorem	pidufd 33571	Every principal ideal domain is a unique factorization domain. (Contributed by Thierry Arnoux, 3-Jun-2025.)
⊢ (𝜑 → 𝑅 ∈ PID)    ⇒   ⊢ (𝜑 → 𝑅 ∈ UFD)
Theorem	1arithufdlem1 33572*	Lemma for 1arithufd 33576. The set 𝑆 of elements which can be written as a product of primes is not empty. (Contributed by Thierry Arnoux, 3-Jun-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    &   ⊢ 𝑈 = (Unit‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 𝑀 = (mulGrp‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ UFD)    &   ⊢ (𝜑 → ¬ 𝑅 ∈ DivRing)    &   ⊢ 𝑆 = {𝑥 ∈ 𝐵 ∣ ∃𝑓 ∈ Word 𝑃𝑥 = (𝑀 Σg 𝑓)}    ⇒   ⊢ (𝜑 → 𝑆 ≠ ∅)
Theorem	1arithufdlem2 33573*	Lemma for 1arithufd 33576. The set 𝑆 of elements which can be written as a product of primes is multiplicatively closed. (Contributed by Thierry Arnoux, 3-Jun-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    &   ⊢ 𝑈 = (Unit‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 𝑀 = (mulGrp‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ UFD)    &   ⊢ (𝜑 → ¬ 𝑅 ∈ DivRing)    &   ⊢ 𝑆 = {𝑥 ∈ 𝐵 ∣ ∃𝑓 ∈ Word 𝑃𝑥 = (𝑀 Σg 𝑓)}    &   ⊢ · = (.r‘𝑅)    &   ⊢ (𝜑 → 𝑋 ∈ 𝑆)    &   ⊢ (𝜑 → 𝑌 ∈ 𝑆)    ⇒   ⊢ (𝜑 → (𝑋 · 𝑌) ∈ 𝑆)
Theorem	1arithufdlem3 33574*	Lemma for 1arithufd 33576. If a product (𝑌 · 𝑋) can be written as a product of primes, with 𝑋 non-unit, nonzero, so can 𝑋. (Contributed by Thierry Arnoux, 3-Jun-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    &   ⊢ 𝑈 = (Unit‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 𝑀 = (mulGrp‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ UFD)    &   ⊢ (𝜑 → ¬ 𝑅 ∈ DivRing)    &   ⊢ 𝑆 = {𝑥 ∈ 𝐵 ∣ ∃𝑓 ∈ Word 𝑃𝑥 = (𝑀 Σg 𝑓)}    &   ⊢ (𝜑 → 𝑋 ∈ 𝐵)    &   ⊢ (𝜑 → ¬ 𝑋 ∈ 𝑈)    &   ⊢ (𝜑 → 𝑋 ≠ 0 )    &   ⊢ · = (.r‘𝑅)    &   ⊢ (𝜑 → 𝑌 ∈ 𝐵)    &   ⊢ (𝜑 → (𝑌 · 𝑋) ∈ 𝑆)    ⇒   ⊢ (𝜑 → 𝑋 ∈ 𝑆)
Theorem	1arithufdlem4 33575*	Lemma for 1arithufd 33576. Nonzero ring, non-field case. Those trivial cases are handled in the final proof. (Contributed by Thierry Arnoux, 3-Jun-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    &   ⊢ 𝑈 = (Unit‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 𝑀 = (mulGrp‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ UFD)    &   ⊢ (𝜑 → ¬ 𝑅 ∈ DivRing)    &   ⊢ 𝑆 = {𝑥 ∈ 𝐵 ∣ ∃𝑓 ∈ Word 𝑃𝑥 = (𝑀 Σg 𝑓)}    &   ⊢ (𝜑 → 𝑋 ∈ 𝐵)    &   ⊢ (𝜑 → ¬ 𝑋 ∈ 𝑈)    &   ⊢ (𝜑 → 𝑋 ≠ 0 )    ⇒   ⊢ (𝜑 → 𝑋 ∈ 𝑆)
Theorem	1arithufd 33576*	Existence of a factorization into irreducible elements in a unique factorization domain. Any non-zero, non-unit element 𝑋 of a UFD 𝑅 can be written as a product of primes 𝑓. As shown in 1arithidom 33565, that factorization is unique, up to the order of the factors and multiplication by units. (Contributed by Thierry Arnoux, 3-Jun-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    &   ⊢ 𝑈 = (Unit‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 𝑀 = (mulGrp‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ UFD)    &   ⊢ (𝜑 → 𝑋 ∈ 𝐵)    &   ⊢ (𝜑 → ¬ 𝑋 ∈ 𝑈)    &   ⊢ (𝜑 → 𝑋 ≠ 0 )    ⇒   ⊢ (𝜑 → ∃𝑓 ∈ Word 𝑃𝑋 = (𝑀 Σg 𝑓))
Theorem	dfufd2lem 33577	Lemma for dfufd2 33578. (Contributed by Thierry Arnoux, 6-Jun-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    &   ⊢ 𝑈 = (Unit‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 𝑀 = (mulGrp‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ IDomn)    &   ⊢ (𝜑 → 𝐼 ∈ (PrmIdeal‘𝑅))    &   ⊢ (𝜑 → 𝐹 ∈ Word 𝑃)    &   ⊢ (𝜑 → (𝑀 Σg 𝐹) ∈ 𝐼)    &   ⊢ (𝜑 → (𝑀 Σg 𝐹) ≠ 0 )    ⇒   ⊢ (𝜑 → (𝐼 ∩ 𝑃) ≠ ∅)
Theorem	dfufd2 33578*	Alternative definition of unique factorization domain (UFD). This is often the textbook definition. Chapter VII, Paragraph 3, Section 3, Proposition 2 of [BourbakiCAlg2], p. 228. (Contributed by Thierry Arnoux, 6-Jun-2025.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    &   ⊢ 𝑈 = (Unit‘𝑅)    &   ⊢ 𝑃 = (RPrime‘𝑅)    &   ⊢ 𝑀 = (mulGrp‘𝑅)    ⇒   ⊢ (𝑅 ∈ UFD ↔ (𝑅 ∈ IDomn ∧ ∀𝑥 ∈ ((𝐵 ∖ 𝑈) ∖ { 0 })∃𝑓 ∈ Word 𝑃𝑥 = (𝑀 Σg 𝑓)))
21.3.10.45  The ring of integers
Theorem	zringidom 33579	The ring of integers is an integral domain. (Contributed by Thierry Arnoux, 4-May-2025.)
⊢ ℤring ∈ IDomn
Theorem	zringpid 33580	The ring of integers is a principal ideal domain. (Contributed by Thierry Arnoux, 18-May-2025.)
⊢ ℤring ∈ PID
Theorem	dfprm3 33581	The (positive) prime elements of the integer ring are the prime numbers. (Contributed by Thierry Arnoux, 18-May-2025.)
⊢ ℙ = (ℕ ∩ (RPrime‘ℤring))
Theorem	zringfrac 33582*	The field of fractions of the ring of integers is isomorphic to the field of the rational numbers. (Contributed by Thierry Arnoux, 4-May-2025.)
⊢ 𝑄 = (ℂfld ↾s ℚ)    &   ⊢ ∼ = (ℤring ~RL (ℤ ∖ {0}))    &   ⊢ 𝐹 = (𝑞 ∈ ℚ ↦ [⟨(numer‘𝑞), (denom‘𝑞)⟩] ∼ )    ⇒   ⊢ 𝐹 ∈ (𝑄 RingIso ( Frac ‘ℤring))
21.3.10.46  Univariate Polynomials
Theorem	0ringmon1p 33583	There are no monic polynomials over a zero ring. (Contributed by Thierry Arnoux, 5-Feb-2025.)
⊢ 𝑀 = (Monic1p‘𝑅)    &   ⊢ 𝐵 = (Base‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ Ring)    &   ⊢ (𝜑 → (♯‘𝐵) = 1)    ⇒   ⊢ (𝜑 → 𝑀 = ∅)
Theorem	fply1 33584	Conditions for a function to be a univariate polynomial. (Contributed by Thierry Arnoux, 19-Aug-2023.)
⊢ 0 = (0g‘𝑅)    &   ⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑃 = (Base‘(Poly1‘𝑅))    &   ⊢ (𝜑 → 𝐹:(ℕ0 ↑m 1o)⟶𝐵)    &   ⊢ (𝜑 → 𝐹 finSupp 0 )    ⇒   ⊢ (𝜑 → 𝐹 ∈ 𝑃)
Theorem	ply1lvec 33585	In a division ring, the univariate polynomials form a vector space. (Contributed by Thierry Arnoux, 19-Feb-2025.)
⊢ 𝑃 = (Poly1‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ DivRing)    ⇒   ⊢ (𝜑 → 𝑃 ∈ LVec)
Theorem	evls1fn 33586	Functionality of the subring polynomial evaluation. (Contributed by Thierry Arnoux, 9-Feb-2025.)
⊢ 𝑂 = (𝑅 evalSub1 𝑆)    &   ⊢ 𝑃 = (Poly1‘(𝑅 ↾s 𝑆))    &   ⊢ 𝑈 = (Base‘𝑃)    &   ⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ (𝜑 → 𝑆 ∈ (SubRing‘𝑅))    ⇒   ⊢ (𝜑 → 𝑂 Fn 𝑈)
Theorem	evls1dm 33587	The domain of the subring polynomial evaluation function. (Contributed by Thierry Arnoux, 9-Feb-2025.)
⊢ 𝑂 = (𝑅 evalSub1 𝑆)    &   ⊢ 𝑃 = (Poly1‘(𝑅 ↾s 𝑆))    &   ⊢ 𝑈 = (Base‘𝑃)    &   ⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ (𝜑 → 𝑆 ∈ (SubRing‘𝑅))    ⇒   ⊢ (𝜑 → dom 𝑂 = 𝑈)
Theorem	evls1fvf 33588	The subring evaluation function for a univariate polynomial as a function, with domain and codomain. (Contributed by Thierry Arnoux, 22-Mar-2025.)
⊢ 𝑂 = (𝑅 evalSub1 𝑆)    &   ⊢ 𝑃 = (Poly1‘(𝑅 ↾s 𝑆))    &   ⊢ 𝑈 = (Base‘𝑃)    &   ⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ (𝜑 → 𝑆 ∈ (SubRing‘𝑅))    &   ⊢ 𝐵 = (Base‘𝑅)    &   ⊢ (𝜑 → 𝑄 ∈ 𝑈)    ⇒   ⊢ (𝜑 → (𝑂‘𝑄):𝐵⟶𝐵)
Theorem	evl1fvf 33589	The univariate polynomial evaluation function as a function, with domain and codomain. (Contributed by Thierry Arnoux, 8-Jun-2025.)
⊢ 𝑂 = (eval1‘𝑅)    &   ⊢ 𝑃 = (Poly1‘𝑅)    &   ⊢ 𝑈 = (Base‘𝑃)    &   ⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ 𝐵 = (Base‘𝑅)    &   ⊢ (𝜑 → 𝑄 ∈ 𝑈)    ⇒   ⊢ (𝜑 → (𝑂‘𝑄):𝐵⟶𝐵)
Theorem	evl1fpws 33590*	Evaluation of a univariate polynomial as a function in a power series. (Contributed by Thierry Arnoux, 23-Jan-2025.)
⊢ 𝑂 = (eval1‘𝑅)    &   ⊢ 𝑊 = (Poly1‘𝑅)    &   ⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑈 = (Base‘𝑊)    &   ⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ (𝜑 → 𝑀 ∈ 𝑈)    &   ⊢ · = (.r‘𝑅)    &   ⊢ ↑ = (.g‘(mulGrp‘𝑅))    &   ⊢ 𝐴 = (coe1‘𝑀)    ⇒   ⊢ (𝜑 → (𝑂‘𝑀) = (𝑥 ∈ 𝐵 ↦ (𝑅 Σg (𝑘 ∈ ℕ0 ↦ ((𝐴‘𝑘) · (𝑘 ↑ 𝑥))))))
Theorem	ressdeg1 33591	The degree of a univariate polynomial in a structure restriction. (Contributed by Thierry Arnoux, 20-Jan-2025.)
⊢ 𝐻 = (𝑅 ↾s 𝑇)    &   ⊢ 𝐷 = (deg1‘𝑅)    &   ⊢ 𝑈 = (Poly1‘𝐻)    &   ⊢ 𝐵 = (Base‘𝑈)    &   ⊢ (𝜑 → 𝑃 ∈ 𝐵)    &   ⊢ (𝜑 → 𝑇 ∈ (SubRing‘𝑅))    ⇒   ⊢ (𝜑 → (𝐷‘𝑃) = ((deg1‘𝐻)‘𝑃))
Theorem	ressply10g 33592	A restricted polynomial algebra has the same group identity (zero polynomial). (Contributed by Thierry Arnoux, 20-Jan-2025.)
⊢ 𝑆 = (Poly1‘𝑅)    &   ⊢ 𝐻 = (𝑅 ↾s 𝑇)    &   ⊢ 𝑈 = (Poly1‘𝐻)    &   ⊢ 𝐵 = (Base‘𝑈)    &   ⊢ (𝜑 → 𝑇 ∈ (SubRing‘𝑅))    &   ⊢ 𝑍 = (0g‘𝑆)    ⇒   ⊢ (𝜑 → 𝑍 = (0g‘𝑈))
Theorem	ressply1mon1p 33593	The monic polynomials of a restricted polynomial algebra. (Contributed by Thierry Arnoux, 21-Jan-2025.)
⊢ 𝑆 = (Poly1‘𝑅)    &   ⊢ 𝐻 = (𝑅 ↾s 𝑇)    &   ⊢ 𝑈 = (Poly1‘𝐻)    &   ⊢ 𝐵 = (Base‘𝑈)    &   ⊢ (𝜑 → 𝑇 ∈ (SubRing‘𝑅))    &   ⊢ 𝑀 = (Monic1p‘𝑅)    &   ⊢ 𝑁 = (Monic1p‘𝐻)    ⇒   ⊢ (𝜑 → 𝑁 = (𝐵 ∩ 𝑀))
Theorem	ressply1invg 33594	An element of a restricted polynomial algebra has the same group inverse. (Contributed by Thierry Arnoux, 30-Jan-2025.)
⊢ 𝑆 = (Poly1‘𝑅)    &   ⊢ 𝐻 = (𝑅 ↾s 𝑇)    &   ⊢ 𝑈 = (Poly1‘𝐻)    &   ⊢ 𝐵 = (Base‘𝑈)    &   ⊢ (𝜑 → 𝑇 ∈ (SubRing‘𝑅))    &   ⊢ 𝑃 = (𝑆 ↾s 𝐵)    &   ⊢ (𝜑 → 𝑋 ∈ 𝐵)    ⇒   ⊢ (𝜑 → ((invg‘𝑈)‘𝑋) = ((invg‘𝑃)‘𝑋))
Theorem	ressply1sub 33595	A restricted polynomial algebra has the same subtraction operation. (Contributed by Thierry Arnoux, 30-Jan-2025.)
⊢ 𝑆 = (Poly1‘𝑅)    &   ⊢ 𝐻 = (𝑅 ↾s 𝑇)    &   ⊢ 𝑈 = (Poly1‘𝐻)    &   ⊢ 𝐵 = (Base‘𝑈)    &   ⊢ (𝜑 → 𝑇 ∈ (SubRing‘𝑅))    &   ⊢ 𝑃 = (𝑆 ↾s 𝐵)    &   ⊢ (𝜑 → 𝑋 ∈ 𝐵)    &   ⊢ (𝜑 → 𝑌 ∈ 𝐵)    ⇒   ⊢ (𝜑 → (𝑋(-g‘𝑈)𝑌) = (𝑋(-g‘𝑃)𝑌))
Theorem	ressasclcl 33596	Closure of the univariate polynomial evaluation for scalars. (Contributed by Thierry Arnoux, 22-Jun-2025.)
⊢ 𝑊 = (Poly1‘𝑈)    &   ⊢ 𝑈 = (𝑆 ↾s 𝑅)    &   ⊢ 𝐴 = (algSc‘𝑊)    &   ⊢ 𝐵 = (Base‘𝑊)    &   ⊢ (𝜑 → 𝑆 ∈ CRing)    &   ⊢ (𝜑 → 𝑅 ∈ (SubRing‘𝑆))    &   ⊢ (𝜑 → 𝑋 ∈ 𝑅)    ⇒   ⊢ (𝜑 → (𝐴‘𝑋) ∈ 𝐵)
Theorem	evls1subd 33597	Univariate polynomial evaluation of a difference of polynomials. (Contributed by Thierry Arnoux, 25-Apr-2025.)
⊢ 𝑄 = (𝑆 evalSub1 𝑅)    &   ⊢ 𝐾 = (Base‘𝑆)    &   ⊢ 𝑊 = (Poly1‘𝑈)    &   ⊢ 𝑈 = (𝑆 ↾s 𝑅)    &   ⊢ 𝐵 = (Base‘𝑊)    &   ⊢ 𝐷 = (-g‘𝑊)    &   ⊢ − = (-g‘𝑆)    &   ⊢ (𝜑 → 𝑆 ∈ CRing)    &   ⊢ (𝜑 → 𝑅 ∈ (SubRing‘𝑆))    &   ⊢ (𝜑 → 𝑀 ∈ 𝐵)    &   ⊢ (𝜑 → 𝑁 ∈ 𝐵)    &   ⊢ (𝜑 → 𝐶 ∈ 𝐾)    ⇒   ⊢ (𝜑 → ((𝑄‘(𝑀𝐷𝑁))‘𝐶) = (((𝑄‘𝑀)‘𝐶) − ((𝑄‘𝑁)‘𝐶)))
Theorem	deg1le0eq0 33598	A polynomial with nonpositive degree is the zero polynomial iff its constant term is zero. Biconditional version of deg1scl 26152. (Contributed by Thierry Arnoux, 22-Mar-2025.)
⊢ 𝐷 = (deg1‘𝑅)    &   ⊢ 𝑃 = (Poly1‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    &   ⊢ 𝐵 = (Base‘𝑃)    &   ⊢ 𝑂 = (0g‘𝑃)    &   ⊢ (𝜑 → 𝑅 ∈ Ring)    &   ⊢ (𝜑 → 𝐹 ∈ 𝐵)    &   ⊢ (𝜑 → (𝐷‘𝐹) ≤ 0)    ⇒   ⊢ (𝜑 → (𝐹 = 𝑂 ↔ ((coe1‘𝐹)‘0) = 0 ))
Theorem	ply1asclunit 33599	A non-zero scalar polynomial over a field 𝐹 is a unit. (Contributed by Thierry Arnoux, 22-Mar-2025.)
⊢ 𝑃 = (Poly1‘𝐹)    &   ⊢ 𝐴 = (algSc‘𝑃)    &   ⊢ 𝐵 = (Base‘𝐹)    &   ⊢ 0 = (0g‘𝐹)    &   ⊢ (𝜑 → 𝐹 ∈ Field)    &   ⊢ (𝜑 → 𝑌 ∈ 𝐵)    &   ⊢ (𝜑 → 𝑌 ≠ 0 )    ⇒   ⊢ (𝜑 → (𝐴‘𝑌) ∈ (Unit‘𝑃))
Theorem	ply1unit 33600	In a field 𝐹, a polynomial 𝐶 is a unit iff it has degree 0. This corresponds to the nonzero scalars, see ply1asclunit 33599. (Contributed by Thierry Arnoux, 25-Apr-2025.)
⊢ 𝑃 = (Poly1‘𝐹)    &   ⊢ 𝐴 = (algSc‘𝑃)    &   ⊢ 𝐵 = (Base‘𝐹)    &   ⊢ 0 = (0g‘𝐹)    &   ⊢ (𝜑 → 𝐹 ∈ Field)    &   ⊢ 𝐷 = (deg1‘𝐹)    &   ⊢ (𝜑 → 𝐶 ∈ (Base‘𝑃))    ⇒   ⊢ (𝜑 → (𝐶 ∈ (Unit‘𝑃) ↔ (𝐷‘𝐶) = 0))