P. 431 of Theorem List - Metamath Proof Explorer

Theorem List for Metamath Proof Explorer - 43001-43100   *Has distinct variable group(s)

Type	Label	Description
Statement
Theorem	flt4lem4 43001	If the product of two coprime factors is a perfect square, the factors are perfect squares. (Contributed by SN, 22-Aug-2024.)
⊢ (𝜑 → 𝐴 ∈ ℕ)    &   ⊢ (𝜑 → 𝐵 ∈ ℕ)    &   ⊢ (𝜑 → 𝐶 ∈ ℕ)    &   ⊢ (𝜑 → (𝐴 gcd 𝐵) = 1)    &   ⊢ (𝜑 → (𝐴 · 𝐵) = (𝐶↑2))    ⇒   ⊢ (𝜑 → (𝐴 = ((𝐴 gcd 𝐶)↑2) ∧ 𝐵 = ((𝐵 gcd 𝐶)↑2)))
Theorem	flt4lem5 43002	In the context of the lemmas of pythagtrip 16774, 𝑀 and 𝑁 are coprime. (Contributed by SN, 23-Aug-2024.)
⊢ 𝑀 = (((√‘(𝐶 + 𝐵)) + (√‘(𝐶 − 𝐵))) / 2)    &   ⊢ 𝑁 = (((√‘(𝐶 + 𝐵)) − (√‘(𝐶 − 𝐵))) / 2)    ⇒   ⊢ (((𝐴 ∈ ℕ ∧ 𝐵 ∈ ℕ ∧ 𝐶 ∈ ℕ) ∧ ((𝐴↑2) + (𝐵↑2)) = (𝐶↑2) ∧ ((𝐴 gcd 𝐵) = 1 ∧ ¬ 2 ∥ 𝐴)) → (𝑀 gcd 𝑁) = 1)
Theorem	flt4lem5elem 43003	Version of fltaccoprm 42992 and fltbccoprm 42993 where 𝑀 is not squared. This can be proved in general for any polynomial in three variables: using prmdvdsncoprmbd 16666, dvds2addd 16231, and prmdvdsexp 16654, we can show that if two variables are coprime, the third is also coprime to the two. (Contributed by SN, 24-Aug-2024.)
⊢ (𝜑 → 𝑀 ∈ ℕ)    &   ⊢ (𝜑 → 𝑅 ∈ ℕ)    &   ⊢ (𝜑 → 𝑆 ∈ ℕ)    &   ⊢ (𝜑 → 𝑀 = ((𝑅↑2) + (𝑆↑2)))    &   ⊢ (𝜑 → (𝑅 gcd 𝑆) = 1)    ⇒   ⊢ (𝜑 → ((𝑅 gcd 𝑀) = 1 ∧ (𝑆 gcd 𝑀) = 1))
Theorem	flt4lem5a 43004	Part 1 of Equation 1 of https://crypto.stanford.edu/pbc/notes/numberfield/fermatn4.html. (Contributed by SN, 22-Aug-2024.)
⊢ 𝑀 = (((√‘(𝐶 + (𝐵↑2))) + (√‘(𝐶 − (𝐵↑2)))) / 2)    &   ⊢ 𝑁 = (((√‘(𝐶 + (𝐵↑2))) − (√‘(𝐶 − (𝐵↑2)))) / 2)    &   ⊢ 𝑅 = (((√‘(𝑀 + 𝑁)) + (√‘(𝑀 − 𝑁))) / 2)    &   ⊢ 𝑆 = (((√‘(𝑀 + 𝑁)) − (√‘(𝑀 − 𝑁))) / 2)    &   ⊢ (𝜑 → 𝐴 ∈ ℕ)    &   ⊢ (𝜑 → 𝐵 ∈ ℕ)    &   ⊢ (𝜑 → 𝐶 ∈ ℕ)    &   ⊢ (𝜑 → ¬ 2 ∥ 𝐴)    &   ⊢ (𝜑 → (𝐴 gcd 𝐶) = 1)    &   ⊢ (𝜑 → ((𝐴↑4) + (𝐵↑4)) = (𝐶↑2))    ⇒   ⊢ (𝜑 → ((𝐴↑2) + (𝑁↑2)) = (𝑀↑2))
Theorem	flt4lem5b 43005	Part 2 of Equation 1 of https://crypto.stanford.edu/pbc/notes/numberfield/fermatn4.html. (Contributed by SN, 22-Aug-2024.)
⊢ 𝑀 = (((√‘(𝐶 + (𝐵↑2))) + (√‘(𝐶 − (𝐵↑2)))) / 2)    &   ⊢ 𝑁 = (((√‘(𝐶 + (𝐵↑2))) − (√‘(𝐶 − (𝐵↑2)))) / 2)    &   ⊢ 𝑅 = (((√‘(𝑀 + 𝑁)) + (√‘(𝑀 − 𝑁))) / 2)    &   ⊢ 𝑆 = (((√‘(𝑀 + 𝑁)) − (√‘(𝑀 − 𝑁))) / 2)    &   ⊢ (𝜑 → 𝐴 ∈ ℕ)    &   ⊢ (𝜑 → 𝐵 ∈ ℕ)    &   ⊢ (𝜑 → 𝐶 ∈ ℕ)    &   ⊢ (𝜑 → ¬ 2 ∥ 𝐴)    &   ⊢ (𝜑 → (𝐴 gcd 𝐶) = 1)    &   ⊢ (𝜑 → ((𝐴↑4) + (𝐵↑4)) = (𝐶↑2))    ⇒   ⊢ (𝜑 → (2 · (𝑀 · 𝑁)) = (𝐵↑2))
Theorem	flt4lem5c 43006	Part 2 of Equation 2 of https://crypto.stanford.edu/pbc/notes/numberfield/fermatn4.html. (Contributed by SN, 22-Aug-2024.)
⊢ 𝑀 = (((√‘(𝐶 + (𝐵↑2))) + (√‘(𝐶 − (𝐵↑2)))) / 2)    &   ⊢ 𝑁 = (((√‘(𝐶 + (𝐵↑2))) − (√‘(𝐶 − (𝐵↑2)))) / 2)    &   ⊢ 𝑅 = (((√‘(𝑀 + 𝑁)) + (√‘(𝑀 − 𝑁))) / 2)    &   ⊢ 𝑆 = (((√‘(𝑀 + 𝑁)) − (√‘(𝑀 − 𝑁))) / 2)    &   ⊢ (𝜑 → 𝐴 ∈ ℕ)    &   ⊢ (𝜑 → 𝐵 ∈ ℕ)    &   ⊢ (𝜑 → 𝐶 ∈ ℕ)    &   ⊢ (𝜑 → ¬ 2 ∥ 𝐴)    &   ⊢ (𝜑 → (𝐴 gcd 𝐶) = 1)    &   ⊢ (𝜑 → ((𝐴↑4) + (𝐵↑4)) = (𝐶↑2))    ⇒   ⊢ (𝜑 → 𝑁 = (2 · (𝑅 · 𝑆)))
Theorem	flt4lem5d 43007	Part 3 of Equation 2 of https://crypto.stanford.edu/pbc/notes/numberfield/fermatn4.html. (Contributed by SN, 23-Aug-2024.)
⊢ 𝑀 = (((√‘(𝐶 + (𝐵↑2))) + (√‘(𝐶 − (𝐵↑2)))) / 2)    &   ⊢ 𝑁 = (((√‘(𝐶 + (𝐵↑2))) − (√‘(𝐶 − (𝐵↑2)))) / 2)    &   ⊢ 𝑅 = (((√‘(𝑀 + 𝑁)) + (√‘(𝑀 − 𝑁))) / 2)    &   ⊢ 𝑆 = (((√‘(𝑀 + 𝑁)) − (√‘(𝑀 − 𝑁))) / 2)    &   ⊢ (𝜑 → 𝐴 ∈ ℕ)    &   ⊢ (𝜑 → 𝐵 ∈ ℕ)    &   ⊢ (𝜑 → 𝐶 ∈ ℕ)    &   ⊢ (𝜑 → ¬ 2 ∥ 𝐴)    &   ⊢ (𝜑 → (𝐴 gcd 𝐶) = 1)    &   ⊢ (𝜑 → ((𝐴↑4) + (𝐵↑4)) = (𝐶↑2))    ⇒   ⊢ (𝜑 → 𝑀 = ((𝑅↑2) + (𝑆↑2)))
Theorem	flt4lem5e 43008	Satisfy the hypotheses of flt4lem4 43001. (Contributed by SN, 23-Aug-2024.)
⊢ 𝑀 = (((√‘(𝐶 + (𝐵↑2))) + (√‘(𝐶 − (𝐵↑2)))) / 2)    &   ⊢ 𝑁 = (((√‘(𝐶 + (𝐵↑2))) − (√‘(𝐶 − (𝐵↑2)))) / 2)    &   ⊢ 𝑅 = (((√‘(𝑀 + 𝑁)) + (√‘(𝑀 − 𝑁))) / 2)    &   ⊢ 𝑆 = (((√‘(𝑀 + 𝑁)) − (√‘(𝑀 − 𝑁))) / 2)    &   ⊢ (𝜑 → 𝐴 ∈ ℕ)    &   ⊢ (𝜑 → 𝐵 ∈ ℕ)    &   ⊢ (𝜑 → 𝐶 ∈ ℕ)    &   ⊢ (𝜑 → ¬ 2 ∥ 𝐴)    &   ⊢ (𝜑 → (𝐴 gcd 𝐶) = 1)    &   ⊢ (𝜑 → ((𝐴↑4) + (𝐵↑4)) = (𝐶↑2))    ⇒   ⊢ (𝜑 → (((𝑅 gcd 𝑆) = 1 ∧ (𝑅 gcd 𝑀) = 1 ∧ (𝑆 gcd 𝑀) = 1) ∧ (𝑅 ∈ ℕ ∧ 𝑆 ∈ ℕ ∧ 𝑀 ∈ ℕ) ∧ ((𝑀 · (𝑅 · 𝑆)) = ((𝐵 / 2)↑2) ∧ (𝐵 / 2) ∈ ℕ)))
Theorem	flt4lem5f 43009	Final equation of https://crypto.stanford.edu/pbc/notes/numberfield/fermatn4.html. Given 𝐴↑4 + 𝐵↑4 = 𝐶↑2, provide a smaller solution. This satisfies the infinite descent condition. (Contributed by SN, 24-Aug-2024.)
⊢ 𝑀 = (((√‘(𝐶 + (𝐵↑2))) + (√‘(𝐶 − (𝐵↑2)))) / 2)    &   ⊢ 𝑁 = (((√‘(𝐶 + (𝐵↑2))) − (√‘(𝐶 − (𝐵↑2)))) / 2)    &   ⊢ 𝑅 = (((√‘(𝑀 + 𝑁)) + (√‘(𝑀 − 𝑁))) / 2)    &   ⊢ 𝑆 = (((√‘(𝑀 + 𝑁)) − (√‘(𝑀 − 𝑁))) / 2)    &   ⊢ (𝜑 → 𝐴 ∈ ℕ)    &   ⊢ (𝜑 → 𝐵 ∈ ℕ)    &   ⊢ (𝜑 → 𝐶 ∈ ℕ)    &   ⊢ (𝜑 → ¬ 2 ∥ 𝐴)    &   ⊢ (𝜑 → (𝐴 gcd 𝐶) = 1)    &   ⊢ (𝜑 → ((𝐴↑4) + (𝐵↑4)) = (𝐶↑2))    ⇒   ⊢ (𝜑 → ((𝑀 gcd (𝐵 / 2))↑2) = (((𝑅 gcd (𝐵 / 2))↑4) + ((𝑆 gcd (𝐵 / 2))↑4)))
Theorem	flt4lem6 43010	Remove shared factors in a solution to 𝐴↑4 + 𝐵↑4 = 𝐶↑2. (Contributed by SN, 24-Jul-2024.)
⊢ (𝜑 → 𝐴 ∈ ℕ)    &   ⊢ (𝜑 → 𝐵 ∈ ℕ)    &   ⊢ (𝜑 → 𝐶 ∈ ℕ)    &   ⊢ (𝜑 → ((𝐴↑4) + (𝐵↑4)) = (𝐶↑2))    ⇒   ⊢ (𝜑 → (((𝐴 / (𝐴 gcd 𝐵)) ∈ ℕ ∧ (𝐵 / (𝐴 gcd 𝐵)) ∈ ℕ ∧ (𝐶 / ((𝐴 gcd 𝐵)↑2)) ∈ ℕ) ∧ (((𝐴 / (𝐴 gcd 𝐵))↑4) + ((𝐵 / (𝐴 gcd 𝐵))↑4)) = ((𝐶 / ((𝐴 gcd 𝐵)↑2))↑2)))
Theorem	flt4lem7 43011*	Convert flt4lem5f 43009 into a convenient form for nna4b4nsq 43012. TODO-SN: The change to (𝐴 gcd 𝐵) = 1 points at some inefficiency in the lemmas. (Contributed by SN, 25-Aug-2024.)
⊢ (𝜑 → 𝐴 ∈ ℕ)    &   ⊢ (𝜑 → 𝐵 ∈ ℕ)    &   ⊢ (𝜑 → 𝐶 ∈ ℕ)    &   ⊢ (𝜑 → ¬ 2 ∥ 𝐴)    &   ⊢ (𝜑 → (𝐴 gcd 𝐵) = 1)    &   ⊢ (𝜑 → ((𝐴↑4) + (𝐵↑4)) = (𝐶↑2))    ⇒   ⊢ (𝜑 → ∃𝑙 ∈ ℕ (∃𝑔 ∈ ℕ ∃ℎ ∈ ℕ (¬ 2 ∥ 𝑔 ∧ ((𝑔 gcd ℎ) = 1 ∧ ((𝑔↑4) + (ℎ↑4)) = (𝑙↑2))) ∧ 𝑙 < 𝐶))
Theorem	nna4b4nsq 43012	Strengthening of Fermat's last theorem for exponent 4, where the sum is only assumed to be a square. (Contributed by SN, 23-Aug-2024.)
⊢ (𝜑 → 𝐴 ∈ ℕ)    &   ⊢ (𝜑 → 𝐵 ∈ ℕ)    &   ⊢ (𝜑 → 𝐶 ∈ ℕ)    ⇒   ⊢ (𝜑 → ((𝐴↑4) + (𝐵↑4)) ≠ (𝐶↑2))
Theorem	fltltc 43013	(𝐶↑𝑁) is the largest term and therefore 𝐵 < 𝐶. (Contributed by Steven Nguyen, 22-Aug-2023.)
⊢ (𝜑 → 𝐴 ∈ ℕ)    &   ⊢ (𝜑 → 𝐵 ∈ ℕ)    &   ⊢ (𝜑 → 𝐶 ∈ ℕ)    &   ⊢ (𝜑 → 𝑁 ∈ (ℤ≥‘3))    &   ⊢ (𝜑 → ((𝐴↑𝑁) + (𝐵↑𝑁)) = (𝐶↑𝑁))    ⇒   ⊢ (𝜑 → 𝐵 < 𝐶)
Theorem	fltnltalem 43014	Lemma for fltnlta 43015. A lower bound for 𝐴 based on pwdif 15803. (Contributed by Steven Nguyen, 22-Aug-2023.)
⊢ (𝜑 → 𝐴 ∈ ℕ)    &   ⊢ (𝜑 → 𝐵 ∈ ℕ)    &   ⊢ (𝜑 → 𝐶 ∈ ℕ)    &   ⊢ (𝜑 → 𝑁 ∈ (ℤ≥‘3))    &   ⊢ (𝜑 → ((𝐴↑𝑁) + (𝐵↑𝑁)) = (𝐶↑𝑁))    ⇒   ⊢ (𝜑 → ((𝐶 − 𝐵) · ((𝐶↑(𝑁 − 1)) + ((𝑁 − 1) · (𝐵↑(𝑁 − 1))))) < (𝐴↑𝑁))
Theorem	fltnlta 43015	In a Fermat counterexample, the exponent 𝑁 is less than all three numbers (𝐴, 𝐵, and 𝐶). Note that 𝐴 < 𝐵 (hypothesis) and 𝐵 < 𝐶 (fltltc 43013). See https://youtu.be/EymVXkPWxyc 43013 for an outline. (Contributed by SN, 24-Aug-2023.)
⊢ (𝜑 → 𝐴 ∈ ℕ)    &   ⊢ (𝜑 → 𝐵 ∈ ℕ)    &   ⊢ (𝜑 → 𝐶 ∈ ℕ)    &   ⊢ (𝜑 → 𝑁 ∈ (ℤ≥‘3))    &   ⊢ (𝜑 → ((𝐴↑𝑁) + (𝐵↑𝑁)) = (𝐶↑𝑁))    &   ⊢ (𝜑 → 𝐴 < 𝐵)    ⇒   ⊢ (𝜑 → 𝑁 < 𝐴)
21.30.9  Exemplar theorems These theorems were added for illustration or pedagogical purposes without the intention of being used, but some may still be moved to main and used, of course.
Theorem	iddii 43016	Version of a1ii 2 with the hypotheses switched. The first hypothesis is redundant so this theorem should not normally appear in a proof. Inference associated with idd 24. (Contributed by SN, 1-Apr-2025.) (New usage is discouraged.)
⊢ 𝜑    &   ⊢ 𝜓    ⇒   ⊢ 𝜓
Theorem	bicomdALT 43017	Alternate proof of bicomd 223 which is shorter after expanding all parent theorems (as of 8-Aug-2024, bicom 222 depends on bicom1 221 and sylib 218 depends on syl 17). Additionally, the labels bicom1 221 and syl 17 happen to contain fewer characters than bicom 222 and sylib 218. However, neither of these conditions count as a shortening according to conventions 30487. In the first case, the criteria could easily be broken by upstream changes, and in many cases the upstream dependency tree is nontrivial (see orass 922 and pm2.31 923). For the latter case, theorem labels are up to revision, so they are not counted in the size of a proof. (Contributed by SN, 21-May-2022.) (New usage is discouraged.) (Proof modification is discouraged.)
⊢ (𝜑 → (𝜓 ↔ 𝜒))    ⇒   ⊢ (𝜑 → (𝜒 ↔ 𝜓))
Theorem	alan 43018	Alias for 19.26 1872 for easier lookup. (Contributed by SN, 12-Aug-2025.) (New usage is discouraged.)
⊢ (∀𝑥(𝜑 ∧ 𝜓) ↔ (∀𝑥𝜑 ∧ ∀𝑥𝜓))
Theorem	exor 43019	Alias for 19.43 1884 for easier lookup. (Contributed by SN, 5-Jul-2025.) (New usage is discouraged.)
⊢ (∃𝑥(𝜑 ∨ 𝜓) ↔ (∃𝑥𝜑 ∨ ∃𝑥𝜓))
Theorem	rexor 43020	Alias for r19.43 3106 for easier lookup. (Contributed by SN, 5-Jul-2025.) (New usage is discouraged.)
⊢ (∃𝑥 ∈ 𝐴 (𝜑 ∨ 𝜓) ↔ (∃𝑥 ∈ 𝐴 𝜑 ∨ ∃𝑥 ∈ 𝐴 𝜓))
Theorem	ruvALT 43021	Alternate proof of ruv 9522 with one fewer syntax step thanks to using elirrv 9514 instead of elirr 9516. However, it does not change the compressed proof size or the number of symbols in the generated display, so it is not considered a shortening according to conventions 30487. (Contributed by SN, 1-Sep-2024.) (New usage is discouraged.) (Proof modification is discouraged.)
⊢ {𝑥 ∣ 𝑥 ∉ 𝑥} = V
Theorem	sn-wcdeq 43022	Alternative to wcdeq 3723 and df-cdeq 3724. This flattens the syntax representation ( wi ( weq vx vy ) wph ) to ( sn-wcdeq vx vy wph ), illustrating the comment of df-cdeq 3724. (Contributed by SN, 26-Sep-2024.) (New usage is discouraged.)
wff (𝑥 = 𝑦 → 𝜑)
Theorem	sq45 43023	45 squared is 2025. (Contributed by SN, 30-Mar-2025.)
⊢ (;45↑2) = ;;;2025
Theorem	sum9cubes 43024	The sum of the first nine perfect cubes is 2025. (Contributed by SN, 30-Mar-2025.)
⊢ Σ𝑘 ∈ (1...9)(𝑘↑3) = ;;;2025
Theorem	sn-isghm 43025*	Longer proof of isghm 19156, unsuccessfully attempting to simplify isghm 19156 using elovmpo 7613 according to an editorial note (now removed). (Contributed by SN, 7-Jun-2025.) (Proof modification is discouraged.) (New usage is discouraged.)
⊢ 𝑋 = (Base‘𝑆)    &   ⊢ 𝑌 = (Base‘𝑇)    &   ⊢ + = (+g‘𝑆)    &   ⊢ ⨣ = (+g‘𝑇)    ⇒   ⊢ (𝐹 ∈ (𝑆 GrpHom 𝑇) ↔ ((𝑆 ∈ Grp ∧ 𝑇 ∈ Grp) ∧ (𝐹:𝑋⟶𝑌 ∧ ∀𝑢 ∈ 𝑋 ∀𝑣 ∈ 𝑋 (𝐹‘(𝑢 + 𝑣)) = ((𝐹‘𝑢) ⨣ (𝐹‘𝑣)))))
Theorem	aprilfools2025 43026	An abuse of notation. (Contributed by Prof. Loof Lirpa, 1-Apr-2025.) (New usage is discouraged.) (Proof modification is discouraged.)
⊢ {⟨“𝐴𝑝𝑟𝑖𝑙”⟩, ⟨“𝑓𝑜𝑜𝑙𝑠!”⟩} ∈ V
21.30.9.1  Standard replacements of ax-10 , ax-11 , ax-12 It is known that ax-10 2147, ax-11 2163, and ax-12 2185 are logically redundant in a weak sense. Practically, they can be replaced with hbn1w 2050, alcomimw 2045, and ax12wlem 2138 as long as you can fully substitute 𝑦 for 𝑥 in the relevant wff (that is, 𝑥 cannot appear in the wff after substituting). This strategy (which I will call a "standard replacement" of axioms) has a lot of potential, for example it works with df-fv 6508 and df-mpt 5182, two very common constructions. But doing a standard replacement of ax-10 2147, ax-11 2163, and ax-12 2185 takes unsatisfyingly long. Usually, if another approach is found, that approach is shorter and better.
Theorem	nfa1w 43027*	Replace ax-10 2147 in nfa1 2157 with a substitution hypothesis. (Contributed by SN, 2-Sep-2025.)
⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓))    ⇒   ⊢ Ⅎ𝑥∀𝑥𝜑
Theorem	eu6w 43028*	Replace ax-10 2147, ax-12 2185 in eu6 2575 with substitution hypotheses. (Contributed by SN, 27-May-2025.)
⊢ (𝑥 = 𝑧 → (𝜑 ↔ 𝜓))    &   ⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜃))    ⇒   ⊢ (∃!𝑥𝜑 ↔ ∃𝑦∀𝑥(𝜑 ↔ 𝑥 = 𝑦))
Theorem	abbibw 43029*	Replace ax-10 2147, ax-11 2163, ax-12 2185 in abbib 2806 with substitution hypotheses. (Contributed by SN, 27-May-2025.)
⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜃))    &   ⊢ (𝑥 = 𝑦 → (𝜓 ↔ 𝜒))    ⇒   ⊢ ({𝑥 ∣ 𝜑} = {𝑥 ∣ 𝜓} ↔ ∀𝑥(𝜑 ↔ 𝜓))
Theorem	absnw 43030*	Replace ax-10 2147, ax-11 2163, ax-12 2185 in absn 4602 with a substitution hypothesis. (Contributed by SN, 27-May-2025.)
⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓))    ⇒   ⊢ ({𝑥 ∣ 𝜑} = {𝑌} ↔ ∀𝑥(𝜑 ↔ 𝑥 = 𝑌))
Theorem	euabsn2w 43031*	Replace ax-10 2147, ax-11 2163, ax-12 2185 in euabsn2 4684 with substitution hypotheses. (Contributed by SN, 27-May-2025.)
⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓))    &   ⊢ (𝑥 = 𝑧 → (𝜑 ↔ 𝜃))    ⇒   ⊢ (∃!𝑥𝜑 ↔ ∃𝑦{𝑥 ∣ 𝜑} = {𝑦})
21.31  Mathbox for Igor Ieskov
Theorem	cu3addd 43032	Cube of sum of three numbers. (Contributed by Igor Ieskov, 14-Dec-2023.)
⊢ (𝜑 → 𝐴 ∈ ℂ)    &   ⊢ (𝜑 → 𝐵 ∈ ℂ)    &   ⊢ (𝜑 → 𝐶 ∈ ℂ)    ⇒   ⊢ (𝜑 → (((𝐴 + 𝐵) + 𝐶)↑3) = (((((𝐴↑3) + (3 · ((𝐴↑2) · 𝐵))) + ((3 · (𝐴 · (𝐵↑2))) + (𝐵↑3))) + (((3 · ((𝐴↑2) · 𝐶)) + (((3 · 2) · (𝐴 · 𝐵)) · 𝐶)) + (3 · ((𝐵↑2) · 𝐶)))) + (((3 · (𝐴 · (𝐶↑2))) + (3 · (𝐵 · (𝐶↑2)))) + (𝐶↑3))))
Theorem	negexpidd 43033	The sum of a real number to the power of N and the negative of the number to the power of N equals zero if N is a nonnegative odd integer. (Contributed by Igor Ieskov, 21-Jan-2024.)
⊢ (𝜑 → 𝐴 ∈ ℝ)    &   ⊢ (𝜑 → 𝑁 ∈ ℕ0)    &   ⊢ (𝜑 → ¬ 2 ∥ 𝑁)    ⇒   ⊢ (𝜑 → ((𝐴↑𝑁) + (-𝐴↑𝑁)) = 0)
Theorem	rexlimdv3d 43034*	An extended version of rexlimdvv 3194 to include three set variables. (Contributed by Igor Ieskov, 21-Jan-2024.)
⊢ (𝜑 → ((𝑥 ∈ 𝐴 ∧ 𝑦 ∈ 𝐵 ∧ 𝑧 ∈ 𝐶) → (𝜓 → 𝜒)))    ⇒   ⊢ (𝜑 → (∃𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 ∃𝑧 ∈ 𝐶 𝜓 → 𝜒))
Theorem	3cubeslem1 43035	Lemma for 3cubes 43041. (Contributed by Igor Ieskov, 22-Jan-2024.)
⊢ (𝜑 → 𝐴 ∈ ℚ)    ⇒   ⊢ (𝜑 → 0 < (((𝐴 + 1)↑2) − 𝐴))
Theorem	3cubeslem2 43036	Lemma for 3cubes 43041. Used to show that the denominators in 3cubeslem4 43040 are nonzero. (Contributed by Igor Ieskov, 22-Jan-2024.)
⊢ (𝜑 → 𝐴 ∈ ℚ)    ⇒   ⊢ (𝜑 → ¬ ((((3↑3) · (𝐴↑2)) + ((3↑2) · 𝐴)) + 3) = 0)
Theorem	3cubeslem3l 43037	Lemma for 3cubes 43041. (Contributed by Igor Ieskov, 22-Jan-2024.)
⊢ (𝜑 → 𝐴 ∈ ℚ)    ⇒   ⊢ (𝜑 → (𝐴 · (((((3↑3) · (𝐴↑2)) + ((3↑2) · 𝐴)) + 3)↑3)) = (((𝐴↑7) · (3↑9)) + (((𝐴↑6) · (3↑9)) + (((𝐴↑5) · ((3↑8) + (3↑8))) + (((𝐴↑4) · (((3↑7) · 2) + (3↑6))) + (((𝐴↑3) · ((3↑6) + (3↑6))) + (((𝐴↑2) · (3↑5)) + (𝐴 · (3↑3)))))))))
Theorem	3cubeslem3r 43038	Lemma for 3cubes 43041. (Contributed by Igor Ieskov, 22-Jan-2024.)
⊢ (𝜑 → 𝐴 ∈ ℚ)    ⇒   ⊢ (𝜑 → ((((((3↑3) · (𝐴↑3)) − 1)↑3) + (((-((3↑3) · (𝐴↑3)) + ((3↑2) · 𝐴)) + 1)↑3)) + ((((3↑3) · (𝐴↑2)) + ((3↑2) · 𝐴))↑3)) = (((𝐴↑7) · (3↑9)) + (((𝐴↑6) · (3↑9)) + (((𝐴↑5) · ((3↑8) + (3↑8))) + (((𝐴↑4) · (((3↑7) · 2) + (3↑6))) + (((𝐴↑3) · ((3↑6) + (3↑6))) + (((𝐴↑2) · (3↑5)) + (𝐴 · (3↑3)))))))))
Theorem	3cubeslem3 43039	Lemma for 3cubes 43041. (Contributed by Igor Ieskov, 22-Jan-2024.)
⊢ (𝜑 → 𝐴 ∈ ℚ)    ⇒   ⊢ (𝜑 → (𝐴 · (((((3↑3) · (𝐴↑2)) + ((3↑2) · 𝐴)) + 3)↑3)) = ((((((3↑3) · (𝐴↑3)) − 1)↑3) + (((-((3↑3) · (𝐴↑3)) + ((3↑2) · 𝐴)) + 1)↑3)) + ((((3↑3) · (𝐴↑2)) + ((3↑2) · 𝐴))↑3)))
Theorem	3cubeslem4 43040	Lemma for 3cubes 43041. This is Ryley's explicit formula for decomposing a rational 𝐴 into a sum of three rational cubes. (Contributed by Igor Ieskov, 22-Jan-2024.)
⊢ (𝜑 → 𝐴 ∈ ℚ)    ⇒   ⊢ (𝜑 → 𝐴 = (((((((3↑3) · (𝐴↑3)) − 1) / ((((3↑3) · (𝐴↑2)) + ((3↑2) · 𝐴)) + 3))↑3) + ((((-((3↑3) · (𝐴↑3)) + ((3↑2) · 𝐴)) + 1) / ((((3↑3) · (𝐴↑2)) + ((3↑2) · 𝐴)) + 3))↑3)) + (((((3↑3) · (𝐴↑2)) + ((3↑2) · 𝐴)) / ((((3↑3) · (𝐴↑2)) + ((3↑2) · 𝐴)) + 3))↑3)))
Theorem	3cubes 43041*	Every rational number is a sum of three rational cubes. See S. Ryley, The Ladies' Diary 122 (1825), 35. (Contributed by Igor Ieskov, 22-Jan-2024.)
⊢ (𝐴 ∈ ℚ ↔ ∃𝑎 ∈ ℚ ∃𝑏 ∈ ℚ ∃𝑐 ∈ ℚ 𝐴 = (((𝑎↑3) + (𝑏↑3)) + (𝑐↑3)))
21.32  Mathbox for OpenAI
Theorem	rntrclfvOAI 43042	The range of the transitive closure is equal to the range of the relation. (Contributed by OpenAI, 7-Jul-2020.)
⊢ (𝑅 ∈ 𝑉 → ran (t+‘𝑅) = ran 𝑅)
21.33  Mathbox for Stefan O'Rear
21.33.1  Additional elementary logic and set theory
Theorem	moxfr 43043*	Transfer at-most-one between related expressions. (Contributed by Stefan O'Rear, 12-Feb-2015.)
⊢ 𝐴 ∈ V    &   ⊢ ∃!𝑦 𝑥 = 𝐴    &   ⊢ (𝑥 = 𝐴 → (𝜑 ↔ 𝜓))    ⇒   ⊢ (∃*𝑥𝜑 ↔ ∃*𝑦𝜓)
21.33.2  Additional theory of functions
Theorem	imaiinfv 43044*	Indexed intersection of an image. (Contributed by Stefan O'Rear, 22-Feb-2015.)
⊢ ((𝐹 Fn 𝐴 ∧ 𝐵 ⊆ 𝐴) → ∩ 𝑥 ∈ 𝐵 (𝐹‘𝑥) = ∩ (𝐹 “ 𝐵))
21.33.3  Additional topology
Theorem	elrfi 43045*	Elementhood in a set of relative finite intersections. (Contributed by Stefan O'Rear, 22-Feb-2015.)
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐶 ⊆ 𝒫 𝐵) → (𝐴 ∈ (fi‘({𝐵} ∪ 𝐶)) ↔ ∃𝑣 ∈ (𝒫 𝐶 ∩ Fin)𝐴 = (𝐵 ∩ ∩ 𝑣)))
Theorem	elrfirn 43046*	Elementhood in a set of relative finite intersections of an indexed family of sets. (Contributed by Stefan O'Rear, 22-Feb-2015.)
⊢ ((𝐵 ∈ 𝑉 ∧ 𝐹:𝐼⟶𝒫 𝐵) → (𝐴 ∈ (fi‘({𝐵} ∪ ran 𝐹)) ↔ ∃𝑣 ∈ (𝒫 𝐼 ∩ Fin)𝐴 = (𝐵 ∩ ∩ 𝑦 ∈ 𝑣 (𝐹‘𝑦))))
Theorem	elrfirn2 43047*	Elementhood in a set of relative finite intersections of an indexed family of sets (implicit). (Contributed by Stefan O'Rear, 22-Feb-2015.)
⊢ ((𝐵 ∈ 𝑉 ∧ ∀𝑦 ∈ 𝐼 𝐶 ⊆ 𝐵) → (𝐴 ∈ (fi‘({𝐵} ∪ ran (𝑦 ∈ 𝐼 ↦ 𝐶))) ↔ ∃𝑣 ∈ (𝒫 𝐼 ∩ Fin)𝐴 = (𝐵 ∩ ∩ 𝑦 ∈ 𝑣 𝐶)))
Theorem	cmpfiiin 43048*	In a compact topology, a system of closed sets with nonempty finite intersections has a nonempty intersection. (Contributed by Stefan O'Rear, 22-Feb-2015.)
⊢ 𝑋 = ∪ 𝐽    &   ⊢ (𝜑 → 𝐽 ∈ Comp)    &   ⊢ ((𝜑 ∧ 𝑘 ∈ 𝐼) → 𝑆 ∈ (Clsd‘𝐽))    &   ⊢ ((𝜑 ∧ (𝑙 ⊆ 𝐼 ∧ 𝑙 ∈ Fin)) → (𝑋 ∩ ∩ 𝑘 ∈ 𝑙 𝑆) ≠ ∅)    ⇒   ⊢ (𝜑 → (𝑋 ∩ ∩ 𝑘 ∈ 𝐼 𝑆) ≠ ∅)
21.33.4  Characterization of closure operators. Kuratowski closure axioms
Theorem	ismrcd1 43049*	Any function from the subsets of a set to itself, which is extensive (satisfies mrcssid 17552), isotone (satisfies mrcss 17551), and idempotent (satisfies mrcidm 17554) has a collection of fixed points which is a Moore collection, and itself is the closure operator for that collection. This can be taken as an alternate definition for the closure operators. This is the first half, ismrcd2 43050 is the second. (Contributed by Stefan O'Rear, 1-Feb-2015.)
⊢ (𝜑 → 𝐵 ∈ 𝑉)    &   ⊢ (𝜑 → 𝐹:𝒫 𝐵⟶𝒫 𝐵)    &   ⊢ ((𝜑 ∧ 𝑥 ⊆ 𝐵) → 𝑥 ⊆ (𝐹‘𝑥))    &   ⊢ ((𝜑 ∧ 𝑥 ⊆ 𝐵 ∧ 𝑦 ⊆ 𝑥) → (𝐹‘𝑦) ⊆ (𝐹‘𝑥))    &   ⊢ ((𝜑 ∧ 𝑥 ⊆ 𝐵) → (𝐹‘(𝐹‘𝑥)) = (𝐹‘𝑥))    ⇒   ⊢ (𝜑 → dom (𝐹 ∩ I ) ∈ (Moore‘𝐵))
Theorem	ismrcd2 43050*	Second half of ismrcd1 43049. (Contributed by Stefan O'Rear, 1-Feb-2015.)
⊢ (𝜑 → 𝐵 ∈ 𝑉)    &   ⊢ (𝜑 → 𝐹:𝒫 𝐵⟶𝒫 𝐵)    &   ⊢ ((𝜑 ∧ 𝑥 ⊆ 𝐵) → 𝑥 ⊆ (𝐹‘𝑥))    &   ⊢ ((𝜑 ∧ 𝑥 ⊆ 𝐵 ∧ 𝑦 ⊆ 𝑥) → (𝐹‘𝑦) ⊆ (𝐹‘𝑥))    &   ⊢ ((𝜑 ∧ 𝑥 ⊆ 𝐵) → (𝐹‘(𝐹‘𝑥)) = (𝐹‘𝑥))    ⇒   ⊢ (𝜑 → 𝐹 = (mrCls‘dom (𝐹 ∩ I )))
Theorem	istopclsd 43051*	A closure function which satisfies sscls 23012, clsidm 23023, cls0 23036, and clsun 36541 defines a (unique) topology which it is the closure function on. (Contributed by Stefan O'Rear, 1-Feb-2015.)
⊢ (𝜑 → 𝐵 ∈ 𝑉)    &   ⊢ (𝜑 → 𝐹:𝒫 𝐵⟶𝒫 𝐵)    &   ⊢ ((𝜑 ∧ 𝑥 ⊆ 𝐵) → 𝑥 ⊆ (𝐹‘𝑥))    &   ⊢ ((𝜑 ∧ 𝑥 ⊆ 𝐵) → (𝐹‘(𝐹‘𝑥)) = (𝐹‘𝑥))    &   ⊢ (𝜑 → (𝐹‘∅) = ∅)    &   ⊢ ((𝜑 ∧ 𝑥 ⊆ 𝐵 ∧ 𝑦 ⊆ 𝐵) → (𝐹‘(𝑥 ∪ 𝑦)) = ((𝐹‘𝑥) ∪ (𝐹‘𝑦)))    &   ⊢ 𝐽 = {𝑧 ∈ 𝒫 𝐵 ∣ (𝐹‘(𝐵 ∖ 𝑧)) = (𝐵 ∖ 𝑧)}    ⇒   ⊢ (𝜑 → (𝐽 ∈ (TopOn‘𝐵) ∧ (cls‘𝐽) = 𝐹))
Theorem	ismrc 43052*	A function is a Moore closure operator iff it satisfies mrcssid 17552, mrcss 17551, and mrcidm 17554. (Contributed by Stefan O'Rear, 1-Feb-2015.)
⊢ (𝐹 ∈ (mrCls “ (Moore‘𝐵)) ↔ (𝐵 ∈ V ∧ 𝐹:𝒫 𝐵⟶𝒫 𝐵 ∧ ∀𝑥∀𝑦((𝑥 ⊆ 𝐵 ∧ 𝑦 ⊆ 𝑥) → (𝑥 ⊆ (𝐹‘𝑥) ∧ (𝐹‘𝑦) ⊆ (𝐹‘𝑥) ∧ (𝐹‘(𝐹‘𝑥)) = (𝐹‘𝑥)))))
21.33.5  Algebraic closure systems
Syntax	cnacs 43053	Class of Noetherian closure systems.
class NoeACS
Definition	df-nacs 43054*	Define a closure system of Noetherian type (not standard terminology) as an algebraic system where all closed sets are finitely generated. (Contributed by Stefan O'Rear, 4-Apr-2015.)
⊢ NoeACS = (𝑥 ∈ V ↦ {𝑐 ∈ (ACS‘𝑥) ∣ ∀𝑠 ∈ 𝑐 ∃𝑔 ∈ (𝒫 𝑥 ∩ Fin)𝑠 = ((mrCls‘𝑐)‘𝑔)})
Theorem	isnacs 43055*	Expand definition of Noetherian-type closure system. (Contributed by Stefan O'Rear, 4-Apr-2015.)
⊢ 𝐹 = (mrCls‘𝐶)    ⇒   ⊢ (𝐶 ∈ (NoeACS‘𝑋) ↔ (𝐶 ∈ (ACS‘𝑋) ∧ ∀𝑠 ∈ 𝐶 ∃𝑔 ∈ (𝒫 𝑋 ∩ Fin)𝑠 = (𝐹‘𝑔)))
Theorem	nacsfg 43056*	In a Noetherian-type closure system, all closed sets are finitely generated. (Contributed by Stefan O'Rear, 4-Apr-2015.)
⊢ 𝐹 = (mrCls‘𝐶)    ⇒   ⊢ ((𝐶 ∈ (NoeACS‘𝑋) ∧ 𝑆 ∈ 𝐶) → ∃𝑔 ∈ (𝒫 𝑋 ∩ Fin)𝑆 = (𝐹‘𝑔))
Theorem	isnacs2 43057	Express Noetherian-type closure system with fewer quantifiers. (Contributed by Stefan O'Rear, 4-Apr-2015.)
⊢ 𝐹 = (mrCls‘𝐶)    ⇒   ⊢ (𝐶 ∈ (NoeACS‘𝑋) ↔ (𝐶 ∈ (ACS‘𝑋) ∧ (𝐹 “ (𝒫 𝑋 ∩ Fin)) = 𝐶))
Theorem	mrefg2 43058*	Slight variation on finite generation for closure systems. (Contributed by Stefan O'Rear, 4-Apr-2015.)
⊢ 𝐹 = (mrCls‘𝐶)    ⇒   ⊢ (𝐶 ∈ (Moore‘𝑋) → (∃𝑔 ∈ (𝒫 𝑋 ∩ Fin)𝑆 = (𝐹‘𝑔) ↔ ∃𝑔 ∈ (𝒫 𝑆 ∩ Fin)𝑆 = (𝐹‘𝑔)))
Theorem	mrefg3 43059*	Slight variation on finite generation for closure systems. (Contributed by Stefan O'Rear, 4-Apr-2015.)
⊢ 𝐹 = (mrCls‘𝐶)    ⇒   ⊢ ((𝐶 ∈ (Moore‘𝑋) ∧ 𝑆 ∈ 𝐶) → (∃𝑔 ∈ (𝒫 𝑋 ∩ Fin)𝑆 = (𝐹‘𝑔) ↔ ∃𝑔 ∈ (𝒫 𝑆 ∩ Fin)𝑆 ⊆ (𝐹‘𝑔)))
Theorem	nacsacs 43060	A closure system of Noetherian type is algebraic. (Contributed by Stefan O'Rear, 4-Apr-2015.)
⊢ (𝐶 ∈ (NoeACS‘𝑋) → 𝐶 ∈ (ACS‘𝑋))
Theorem	isnacs3 43061*	A choice-free order equivalent to the Noetherian condition on a closure system. (Contributed by Stefan O'Rear, 4-Apr-2015.)
⊢ (𝐶 ∈ (NoeACS‘𝑋) ↔ (𝐶 ∈ (Moore‘𝑋) ∧ ∀𝑠 ∈ 𝒫 𝐶((toInc‘𝑠) ∈ Dirset → ∪ 𝑠 ∈ 𝑠)))
Theorem	incssnn0 43062*	Transitivity induction of subsets, lemma for nacsfix 43063. (Contributed by Stefan O'Rear, 4-Apr-2015.)
⊢ ((∀𝑥 ∈ ℕ0 (𝐹‘𝑥) ⊆ (𝐹‘(𝑥 + 1)) ∧ 𝐴 ∈ ℕ0 ∧ 𝐵 ∈ (ℤ≥‘𝐴)) → (𝐹‘𝐴) ⊆ (𝐹‘𝐵))
Theorem	nacsfix 43063*	An increasing sequence of closed sets in a Noetherian-type closure system eventually fixates. (Contributed by Stefan O'Rear, 4-Apr-2015.)
⊢ ((𝐶 ∈ (NoeACS‘𝑋) ∧ 𝐹:ℕ0⟶𝐶 ∧ ∀𝑥 ∈ ℕ0 (𝐹‘𝑥) ⊆ (𝐹‘(𝑥 + 1))) → ∃𝑦 ∈ ℕ0 ∀𝑧 ∈ (ℤ≥‘𝑦)(𝐹‘𝑧) = (𝐹‘𝑦))
21.33.6  Miscellanea 1. Map utilities
Theorem	constmap 43064	A constant (represented without dummy variables) is an element of a function set. Note: In the following development, we will be quite often quantifying over functions and points in N-dimensional space (which are equivalent to functions from an "index set"). Many of the following theorems exist to transfer standard facts about functions to elements of function sets. (Contributed by Stefan O'Rear, 30-Aug-2014.) (Revised by Stefan O'Rear, 5-May-2015.)
⊢ 𝐴 ∈ V    &   ⊢ 𝐶 ∈ V    ⇒   ⊢ (𝐵 ∈ 𝐶 → (𝐴 × {𝐵}) ∈ (𝐶 ↑m 𝐴))
Theorem	mapco2g 43065	Renaming indices in a tuple, with sethood as antecedents. (Contributed by Stefan O'Rear, 9-Oct-2014.) (Revised by Mario Carneiro, 5-May-2015.)
⊢ ((𝐸 ∈ V ∧ 𝐴 ∈ (𝐵 ↑m 𝐶) ∧ 𝐷:𝐸⟶𝐶) → (𝐴 ∘ 𝐷) ∈ (𝐵 ↑m 𝐸))
Theorem	mapco2 43066	Post-composition (renaming indices) of a mapping viewed as a point. (Contributed by Stefan O'Rear, 5-Oct-2014.) (Revised by Stefan O'Rear, 5-May-2015.)
⊢ 𝐸 ∈ V    ⇒   ⊢ ((𝐴 ∈ (𝐵 ↑m 𝐶) ∧ 𝐷:𝐸⟶𝐶) → (𝐴 ∘ 𝐷) ∈ (𝐵 ↑m 𝐸))
Theorem	mapfzcons 43067	Extending a one-based mapping by adding a tuple at the end results in another mapping. (Contributed by Stefan O'Rear, 10-Oct-2014.) (Revised by Stefan O'Rear, 5-May-2015.)
⊢ 𝑀 = (𝑁 + 1)    ⇒   ⊢ ((𝑁 ∈ ℕ0 ∧ 𝐴 ∈ (𝐵 ↑m (1...𝑁)) ∧ 𝐶 ∈ 𝐵) → (𝐴 ∪ {⟨𝑀, 𝐶⟩}) ∈ (𝐵 ↑m (1...𝑀)))
Theorem	mapfzcons1 43068	Recover prefix mapping from an extended mapping. (Contributed by Stefan O'Rear, 10-Oct-2014.) (Revised by Stefan O'Rear, 5-May-2015.)
⊢ 𝑀 = (𝑁 + 1)    ⇒   ⊢ (𝐴 ∈ (𝐵 ↑m (1...𝑁)) → ((𝐴 ∪ {⟨𝑀, 𝐶⟩}) ↾ (1...𝑁)) = 𝐴)
Theorem	mapfzcons1cl 43069	A nonempty mapping has a prefix. (Contributed by Stefan O'Rear, 10-Oct-2014.) (Revised by Stefan O'Rear, 5-May-2015.)
⊢ 𝑀 = (𝑁 + 1)    ⇒   ⊢ (𝐴 ∈ (𝐵 ↑m (1...𝑀)) → (𝐴 ↾ (1...𝑁)) ∈ (𝐵 ↑m (1...𝑁)))
Theorem	mapfzcons2 43070	Recover added element from an extended mapping. (Contributed by Stefan O'Rear, 10-Oct-2014.) (Revised by Stefan O'Rear, 5-May-2015.)
⊢ 𝑀 = (𝑁 + 1)    ⇒   ⊢ ((𝐴 ∈ (𝐵 ↑m (1...𝑁)) ∧ 𝐶 ∈ 𝐵) → ((𝐴 ∪ {⟨𝑀, 𝐶⟩})‘𝑀) = 𝐶)
21.33.7  Miscellanea for polynomials
Theorem	mptfcl 43071*	Interpret range of a maps-to notation as a constraint on the definition. (Contributed by Stefan O'Rear, 10-Oct-2014.)
⊢ ((𝑡 ∈ 𝐴 ↦ 𝐵):𝐴⟶𝐶 → (𝑡 ∈ 𝐴 → 𝐵 ∈ 𝐶))
21.33.8  Multivariate polynomials over the integers
Syntax	cmzpcl 43072	Extend class notation to include pre-polynomial rings.
class mzPolyCld
Syntax	cmzp 43073	Extend class notation to include polynomial rings.
class mzPoly
Definition	df-mzpcl 43074*	Define the polynomially closed function rings over an arbitrary index set 𝑣. The set (mzPolyCld‘𝑣) contains all sets of functions from (ℤ ↑m 𝑣) to ℤ which include all constants and projections and are closed under addition and multiplication. This is a "temporary" set used to define the polynomial function ring itself (mzPoly‘𝑣); see df-mzp 43075. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ mzPolyCld = (𝑣 ∈ V ↦ {𝑝 ∈ 𝒫 (ℤ ↑m (ℤ ↑m 𝑣)) ∣ ((∀𝑖 ∈ ℤ ((ℤ ↑m 𝑣) × {𝑖}) ∈ 𝑝 ∧ ∀𝑗 ∈ 𝑣 (𝑥 ∈ (ℤ ↑m 𝑣) ↦ (𝑥‘𝑗)) ∈ 𝑝) ∧ ∀𝑓 ∈ 𝑝 ∀𝑔 ∈ 𝑝 ((𝑓 ∘f + 𝑔) ∈ 𝑝 ∧ (𝑓 ∘f · 𝑔) ∈ 𝑝))})
Definition	df-mzp 43075	Polynomials over ℤ with an arbitrary index set, that is, the smallest ring of functions containing all constant functions and all projections. This is almost the most general reasonable definition; to reach full generality, we would need to be able to replace ZZ with an arbitrary (semi)ring (and a coordinate subring), but rings have not been defined yet. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ mzPoly = (𝑣 ∈ V ↦ ∩ (mzPolyCld‘𝑣))
Theorem	mzpclval 43076*	Substitution lemma for mzPolyCld. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ (𝑉 ∈ V → (mzPolyCld‘𝑉) = {𝑝 ∈ 𝒫 (ℤ ↑m (ℤ ↑m 𝑉)) ∣ ((∀𝑖 ∈ ℤ ((ℤ ↑m 𝑉) × {𝑖}) ∈ 𝑝 ∧ ∀𝑗 ∈ 𝑉 (𝑥 ∈ (ℤ ↑m 𝑉) ↦ (𝑥‘𝑗)) ∈ 𝑝) ∧ ∀𝑓 ∈ 𝑝 ∀𝑔 ∈ 𝑝 ((𝑓 ∘f + 𝑔) ∈ 𝑝 ∧ (𝑓 ∘f · 𝑔) ∈ 𝑝))})
Theorem	elmzpcl 43077*	Double substitution lemma for mzPolyCld. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ (𝑉 ∈ V → (𝑃 ∈ (mzPolyCld‘𝑉) ↔ (𝑃 ⊆ (ℤ ↑m (ℤ ↑m 𝑉)) ∧ ((∀𝑖 ∈ ℤ ((ℤ ↑m 𝑉) × {𝑖}) ∈ 𝑃 ∧ ∀𝑗 ∈ 𝑉 (𝑥 ∈ (ℤ ↑m 𝑉) ↦ (𝑥‘𝑗)) ∈ 𝑃) ∧ ∀𝑓 ∈ 𝑃 ∀𝑔 ∈ 𝑃 ((𝑓 ∘f + 𝑔) ∈ 𝑃 ∧ (𝑓 ∘f · 𝑔) ∈ 𝑃)))))
Theorem	mzpclall 43078	The set of all functions with the signature of a polynomial is a polynomially closed set. This is a lemma to show that the intersection in df-mzp 43075 is well-defined. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ (𝑉 ∈ V → (ℤ ↑m (ℤ ↑m 𝑉)) ∈ (mzPolyCld‘𝑉))
Theorem	mzpcln0 43079	Corollary of mzpclall 43078: polynomially closed function sets are not empty. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ (𝑉 ∈ V → (mzPolyCld‘𝑉) ≠ ∅)
Theorem	mzpcl1 43080	Defining property 1 of a polynomially closed function set 𝑃: it contains all constant functions. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ ((𝑃 ∈ (mzPolyCld‘𝑉) ∧ 𝐹 ∈ ℤ) → ((ℤ ↑m 𝑉) × {𝐹}) ∈ 𝑃)
Theorem	mzpcl2 43081*	Defining property 2 of a polynomially closed function set 𝑃: it contains all projections. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ ((𝑃 ∈ (mzPolyCld‘𝑉) ∧ 𝐹 ∈ 𝑉) → (𝑔 ∈ (ℤ ↑m 𝑉) ↦ (𝑔‘𝐹)) ∈ 𝑃)
Theorem	mzpcl34 43082	Defining properties 3 and 4 of a polynomially closed function set 𝑃: it is closed under pointwise addition and multiplication. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ ((𝑃 ∈ (mzPolyCld‘𝑉) ∧ 𝐹 ∈ 𝑃 ∧ 𝐺 ∈ 𝑃) → ((𝐹 ∘f + 𝐺) ∈ 𝑃 ∧ (𝐹 ∘f · 𝐺) ∈ 𝑃))
Theorem	mzpval 43083	Value of the mzPoly function. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ (𝑉 ∈ V → (mzPoly‘𝑉) = ∩ (mzPolyCld‘𝑉))
Theorem	dmmzp 43084	mzPoly is defined for all index sets which are sets. This is used with elfvdm 6876 to eliminate sethood antecedents. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ dom mzPoly = V
Theorem	mzpincl 43085	Polynomial closedness is a universal first-order property and passes to intersections. This is where the closure properties of the polynomial ring itself are proved. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ (𝑉 ∈ V → (mzPoly‘𝑉) ∈ (mzPolyCld‘𝑉))
Theorem	mzpconst 43086	Constant functions are polynomial. See also mzpconstmpt 43091. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ ((𝑉 ∈ V ∧ 𝐶 ∈ ℤ) → ((ℤ ↑m 𝑉) × {𝐶}) ∈ (mzPoly‘𝑉))
Theorem	mzpf 43087	A polynomial function is a function from the coordinate space to the integers. (Contributed by Stefan O'Rear, 5-Oct-2014.)
⊢ (𝐹 ∈ (mzPoly‘𝑉) → 𝐹:(ℤ ↑m 𝑉)⟶ℤ)
Theorem	mzpproj 43088*	A projection function is polynomial. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ ((𝑉 ∈ V ∧ 𝑋 ∈ 𝑉) → (𝑔 ∈ (ℤ ↑m 𝑉) ↦ (𝑔‘𝑋)) ∈ (mzPoly‘𝑉))
Theorem	mzpadd 43089	The pointwise sum of two polynomial functions is a polynomial function. See also mzpaddmpt 43092. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ ((𝐴 ∈ (mzPoly‘𝑉) ∧ 𝐵 ∈ (mzPoly‘𝑉)) → (𝐴 ∘f + 𝐵) ∈ (mzPoly‘𝑉))
Theorem	mzpmul 43090	The pointwise product of two polynomial functions is a polynomial function. See also mzpmulmpt 43093. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ ((𝐴 ∈ (mzPoly‘𝑉) ∧ 𝐵 ∈ (mzPoly‘𝑉)) → (𝐴 ∘f · 𝐵) ∈ (mzPoly‘𝑉))
Theorem	mzpconstmpt 43091*	A constant function expressed in maps-to notation is polynomial. This theorem and the several that follow (mzpaddmpt 43092, mzpmulmpt 43093, mzpnegmpt 43095, mzpsubmpt 43094, mzpexpmpt 43096) can be used to build proofs that functions which are "manifestly polynomial", in the sense of being a maps-to containing constants, projections, and simple arithmetic operations, are actually polynomial functions. There is no mzpprojmpt because mzpproj 43088 is already expressed using maps-to notation. (Contributed by Stefan O'Rear, 5-Oct-2014.)
⊢ ((𝑉 ∈ V ∧ 𝐶 ∈ ℤ) → (𝑥 ∈ (ℤ ↑m 𝑉) ↦ 𝐶) ∈ (mzPoly‘𝑉))
Theorem	mzpaddmpt 43092*	Sum of polynomial functions is polynomial. Maps-to version of mzpadd 43089. (Contributed by Stefan O'Rear, 5-Oct-2014.)
⊢ (((𝑥 ∈ (ℤ ↑m 𝑉) ↦ 𝐴) ∈ (mzPoly‘𝑉) ∧ (𝑥 ∈ (ℤ ↑m 𝑉) ↦ 𝐵) ∈ (mzPoly‘𝑉)) → (𝑥 ∈ (ℤ ↑m 𝑉) ↦ (𝐴 + 𝐵)) ∈ (mzPoly‘𝑉))
Theorem	mzpmulmpt 43093*	Product of polynomial functions is polynomial. Maps-to version of mzpmulmpt 43093. (Contributed by Stefan O'Rear, 5-Oct-2014.)
⊢ (((𝑥 ∈ (ℤ ↑m 𝑉) ↦ 𝐴) ∈ (mzPoly‘𝑉) ∧ (𝑥 ∈ (ℤ ↑m 𝑉) ↦ 𝐵) ∈ (mzPoly‘𝑉)) → (𝑥 ∈ (ℤ ↑m 𝑉) ↦ (𝐴 · 𝐵)) ∈ (mzPoly‘𝑉))
Theorem	mzpsubmpt 43094*	The difference of two polynomial functions is polynomial. (Contributed by Stefan O'Rear, 10-Oct-2014.)
⊢ (((𝑥 ∈ (ℤ ↑m 𝑉) ↦ 𝐴) ∈ (mzPoly‘𝑉) ∧ (𝑥 ∈ (ℤ ↑m 𝑉) ↦ 𝐵) ∈ (mzPoly‘𝑉)) → (𝑥 ∈ (ℤ ↑m 𝑉) ↦ (𝐴 − 𝐵)) ∈ (mzPoly‘𝑉))
Theorem	mzpnegmpt 43095*	Negation of a polynomial function. (Contributed by Stefan O'Rear, 11-Oct-2014.)
⊢ ((𝑥 ∈ (ℤ ↑m 𝑉) ↦ 𝐴) ∈ (mzPoly‘𝑉) → (𝑥 ∈ (ℤ ↑m 𝑉) ↦ -𝐴) ∈ (mzPoly‘𝑉))
Theorem	mzpexpmpt 43096*	Raise a polynomial function to a (fixed) exponent. (Contributed by Stefan O'Rear, 5-Oct-2014.)
⊢ (((𝑥 ∈ (ℤ ↑m 𝑉) ↦ 𝐴) ∈ (mzPoly‘𝑉) ∧ 𝐷 ∈ ℕ0) → (𝑥 ∈ (ℤ ↑m 𝑉) ↦ (𝐴↑𝐷)) ∈ (mzPoly‘𝑉))
Theorem	mzpindd 43097*	"Structural" induction to prove properties of all polynomial functions. (Contributed by Stefan O'Rear, 4-Oct-2014.)
⊢ ((𝜑 ∧ 𝑓 ∈ ℤ) → 𝜒)    &   ⊢ ((𝜑 ∧ 𝑓 ∈ 𝑉) → 𝜃)    &   ⊢ ((𝜑 ∧ (𝑓:(ℤ ↑m 𝑉)⟶ℤ ∧ 𝜏) ∧ (𝑔:(ℤ ↑m 𝑉)⟶ℤ ∧ 𝜂)) → 𝜁)    &   ⊢ ((𝜑 ∧ (𝑓:(ℤ ↑m 𝑉)⟶ℤ ∧ 𝜏) ∧ (𝑔:(ℤ ↑m 𝑉)⟶ℤ ∧ 𝜂)) → 𝜎)    &   ⊢ (𝑥 = ((ℤ ↑m 𝑉) × {𝑓}) → (𝜓 ↔ 𝜒))    &   ⊢ (𝑥 = (𝑔 ∈ (ℤ ↑m 𝑉) ↦ (𝑔‘𝑓)) → (𝜓 ↔ 𝜃))    &   ⊢ (𝑥 = 𝑓 → (𝜓 ↔ 𝜏))    &   ⊢ (𝑥 = 𝑔 → (𝜓 ↔ 𝜂))    &   ⊢ (𝑥 = (𝑓 ∘f + 𝑔) → (𝜓 ↔ 𝜁))    &   ⊢ (𝑥 = (𝑓 ∘f · 𝑔) → (𝜓 ↔ 𝜎))    &   ⊢ (𝑥 = 𝐴 → (𝜓 ↔ 𝜌))    ⇒   ⊢ ((𝜑 ∧ 𝐴 ∈ (mzPoly‘𝑉)) → 𝜌)
Theorem	mzpmfp 43098	Relationship between multivariate Z-polynomials and general multivariate polynomial functions. (Contributed by Stefan O'Rear, 20-Mar-2015.) (Revised by AV, 13-Jun-2019.)
⊢ (mzPoly‘𝐼) = ran (𝐼 eval ℤring)
Theorem	mzpsubst 43099*	Substituting polynomials for the variables of a polynomial results in a polynomial. 𝐺 is expected to depend on 𝑦 and provide the polynomials which are being substituted. (Contributed by Stefan O'Rear, 5-Oct-2014.)
⊢ ((𝑊 ∈ V ∧ 𝐹 ∈ (mzPoly‘𝑉) ∧ ∀𝑦 ∈ 𝑉 𝐺 ∈ (mzPoly‘𝑊)) → (𝑥 ∈ (ℤ ↑m 𝑊) ↦ (𝐹‘(𝑦 ∈ 𝑉 ↦ (𝐺‘𝑥)))) ∈ (mzPoly‘𝑊))
Theorem	mzprename 43100*	Simplified version of mzpsubst 43099 to simply relabel variables in a polynomial. (Contributed by Stefan O'Rear, 5-Oct-2014.)
⊢ ((𝑊 ∈ V ∧ 𝐹 ∈ (mzPoly‘𝑉) ∧ 𝑅:𝑉⟶𝑊) → (𝑥 ∈ (ℤ ↑m 𝑊) ↦ (𝐹‘(𝑥 ∘ 𝑅))) ∈ (mzPoly‘𝑊))