P. 320 of Theorem List - Metamath Proof Explorer

Theorem List for Metamath Proof Explorer - 31901-32000   *Has distinct variable group(s)

Type	Label	Description
Statement
Theorem	xrge0tps 31901	The extended nonnegative real numbers monoid forms a topological space. (Contributed by Thierry Arnoux, 19-Jun-2017.)
⊢ (ℝ*𝑠 ↾s (0[,]+∞)) ∈ TopSp
Theorem	xrge0topn 31902	The topology of the extended nonnegative real numbers. (Contributed by Thierry Arnoux, 20-Jun-2017.)
⊢ (TopOpen‘(ℝ*𝑠 ↾s (0[,]+∞))) = ((ordTop‘ ≤ ) ↾t (0[,]+∞))
Theorem	xrge0haus 31903	The topology of the extended nonnegative real numbers is Hausdorff. (Contributed by Thierry Arnoux, 26-Jul-2017.)
⊢ (TopOpen‘(ℝ*𝑠 ↾s (0[,]+∞))) ∈ Haus
Theorem	xrge0tmd 31904	The extended nonnegative real numbers monoid is a topological monoid. (Contributed by Thierry Arnoux, 26-Mar-2017.) (Proof Shortened by Thierry Arnoux, 21-Jun-2017.)
⊢ (ℝ*𝑠 ↾s (0[,]+∞)) ∈ TopMnd
Theorem	xrge0tmdALT 31905	Alternate proof of xrge0tmd 31904. (Contributed by Thierry Arnoux, 26-Mar-2017.) (Proof modification is discouraged.) (New usage is discouraged.)
⊢ (ℝ*𝑠 ↾s (0[,]+∞)) ∈ TopMnd
20.3.12.15  Limits - misc additions
Theorem	lmlim 31906	Relate a limit in a given topology to a complex number limit, provided that topology agrees with the common topology on ℂ on the required subset. (Contributed by Thierry Arnoux, 11-Jul-2017.)
⊢ 𝐽 ∈ (TopOn‘𝑌)    &   ⊢ (𝜑 → 𝐹:ℕ⟶𝑋)    &   ⊢ (𝜑 → 𝑃 ∈ 𝑋)    &   ⊢ (𝐽 ↾t 𝑋) = ((TopOpen‘ℂfld) ↾t 𝑋)    &   ⊢ 𝑋 ⊆ ℂ    ⇒   ⊢ (𝜑 → (𝐹(⇝𝑡‘𝐽)𝑃 ↔ 𝐹 ⇝ 𝑃))
Theorem	lmlimxrge0 31907	Relate a limit in the nonnegative extended reals to a complex limit, provided the considered function is a real function. (Contributed by Thierry Arnoux, 11-Jul-2017.)
⊢ 𝐽 = (TopOpen‘(ℝ*𝑠 ↾s (0[,]+∞)))    &   ⊢ (𝜑 → 𝐹:ℕ⟶𝑋)    &   ⊢ (𝜑 → 𝑃 ∈ 𝑋)    &   ⊢ 𝑋 ⊆ (0[,)+∞)    ⇒   ⊢ (𝜑 → (𝐹(⇝𝑡‘𝐽)𝑃 ↔ 𝐹 ⇝ 𝑃))
Theorem	rge0scvg 31908	Implication of convergence for a nonnegative series. This could be used to shorten prmreclem6 16631. (Contributed by Thierry Arnoux, 28-Jul-2017.)
⊢ ((𝐹:ℕ⟶(0[,)+∞) ∧ seq1( + , 𝐹) ∈ dom ⇝ ) → sup(ran seq1( + , 𝐹), ℝ, < ) ∈ ℝ)
Theorem	fsumcvg4 31909	A serie with finite support is a finite sum, and therefore converges. (Contributed by Thierry Arnoux, 6-Sep-2017.) (Revised by Thierry Arnoux, 1-Sep-2019.)
⊢ 𝑆 = (ℤ≥‘𝑀)    &   ⊢ (𝜑 → 𝑀 ∈ ℤ)    &   ⊢ (𝜑 → 𝐹:𝑆⟶ℂ)    &   ⊢ (𝜑 → (◡𝐹 “ (ℂ ∖ {0})) ∈ Fin)    ⇒   ⊢ (𝜑 → seq𝑀( + , 𝐹) ∈ dom ⇝ )
Theorem	pnfneige0 31910*	A neighborhood of +∞ contains an unbounded interval based at a real number. See pnfnei 22380. (Contributed by Thierry Arnoux, 31-Jul-2017.)
⊢ 𝐽 = (TopOpen‘(ℝ*𝑠 ↾s (0[,]+∞)))    ⇒   ⊢ ((𝐴 ∈ 𝐽 ∧ +∞ ∈ 𝐴) → ∃𝑥 ∈ ℝ (𝑥(,]+∞) ⊆ 𝐴)
Theorem	lmxrge0 31911*	Express "sequence 𝐹 converges to plus infinity" (i.e. diverges), for a sequence of nonnegative extended real numbers. (Contributed by Thierry Arnoux, 2-Aug-2017.)
⊢ 𝐽 = (TopOpen‘(ℝ*𝑠 ↾s (0[,]+∞)))    &   ⊢ (𝜑 → 𝐹:ℕ⟶(0[,]+∞))    &   ⊢ ((𝜑 ∧ 𝑘 ∈ ℕ) → (𝐹‘𝑘) = 𝐴)    ⇒   ⊢ (𝜑 → (𝐹(⇝𝑡‘𝐽)+∞ ↔ ∀𝑥 ∈ ℝ ∃𝑗 ∈ ℕ ∀𝑘 ∈ (ℤ≥‘𝑗)𝑥 < 𝐴))
Theorem	lmdvg 31912*	If a monotonic sequence of real numbers diverges, it is unbounded. (Contributed by Thierry Arnoux, 4-Aug-2017.)
⊢ (𝜑 → 𝐹:ℕ⟶(0[,)+∞))    &   ⊢ ((𝜑 ∧ 𝑘 ∈ ℕ) → (𝐹‘𝑘) ≤ (𝐹‘(𝑘 + 1)))    &   ⊢ (𝜑 → ¬ 𝐹 ∈ dom ⇝ )    ⇒   ⊢ (𝜑 → ∀𝑥 ∈ ℝ ∃𝑗 ∈ ℕ ∀𝑘 ∈ (ℤ≥‘𝑗)𝑥 < (𝐹‘𝑘))
Theorem	lmdvglim 31913*	If a monotonic real number sequence 𝐹 diverges, it converges in the extended real numbers and its limit is plus infinity. (Contributed by Thierry Arnoux, 3-Aug-2017.)
⊢ 𝐽 = (TopOpen‘(ℝ*𝑠 ↾s (0[,]+∞)))    &   ⊢ (𝜑 → 𝐹:ℕ⟶(0[,)+∞))    &   ⊢ ((𝜑 ∧ 𝑘 ∈ ℕ) → (𝐹‘𝑘) ≤ (𝐹‘(𝑘 + 1)))    &   ⊢ (𝜑 → ¬ 𝐹 ∈ dom ⇝ )    ⇒   ⊢ (𝜑 → 𝐹(⇝𝑡‘𝐽)+∞)
20.3.12.16  Univariate polynomials
Theorem	pl1cn 31914	A univariate polynomial is continuous. (Contributed by Thierry Arnoux, 17-Sep-2018.)
⊢ 𝑃 = (Poly1‘𝑅)    &   ⊢ 𝐸 = (eval1‘𝑅)    &   ⊢ 𝐵 = (Base‘𝑃)    &   ⊢ 𝐾 = (Base‘𝑅)    &   ⊢ 𝐽 = (TopOpen‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ CRing)    &   ⊢ (𝜑 → 𝑅 ∈ TopRing)    &   ⊢ (𝜑 → 𝐹 ∈ 𝐵)    ⇒   ⊢ (𝜑 → (𝐸‘𝐹) ∈ (𝐽 Cn 𝐽))
20.3.13  Uniform Stuctures and Spaces
20.3.13.1  Hausdorff uniform completion
Syntax	chcmp 31915	Extend class notation with the Hausdorff uniform completion relation.
class HCmp
Definition	df-hcmp 31916*	Definition of the Hausdorff completion. In this definition, a structure 𝑤 is a Hausdorff completion of a uniform structure 𝑢 if 𝑤 is a complete uniform space, in which 𝑢 is dense, and which admits the same uniform structure. Theorem 3 of [BourbakiTop1] p. II.21. states the existence and uniqueness of such a completion. (Contributed by Thierry Arnoux, 5-Mar-2018.)
⊢ HCmp = {⟨𝑢, 𝑤⟩ ∣ ((𝑢 ∈ ∪ ran UnifOn ∧ 𝑤 ∈ CUnifSp) ∧ ((UnifSt‘𝑤) ↾t dom ∪ 𝑢) = 𝑢 ∧ ((cls‘(TopOpen‘𝑤))‘dom ∪ 𝑢) = (Base‘𝑤))}
20.3.14  Topology and algebraic structures
20.3.14.1  The norm on the ring of the integer numbers
Theorem	zringnm 31917	The norm (function) for a ring of integers is the absolute value function (restricted to the integers). (Contributed by AV, 13-Jun-2019.)
⊢ (norm‘ℤring) = (abs ↾ ℤ)
Theorem	zzsnm 31918	The norm of the ring of the integers. (Contributed by Thierry Arnoux, 8-Nov-2017.) (Revised by AV, 13-Jun-2019.)
⊢ (𝑀 ∈ ℤ → (abs‘𝑀) = ((norm‘ℤring)‘𝑀))
20.3.14.2  Topological ` ZZ ` -modules
Theorem	zlm0 31919	Zero of a ℤ-module. (Contributed by Thierry Arnoux, 8-Nov-2017.)
⊢ 𝑊 = (ℤMod‘𝐺)    &   ⊢ 0 = (0g‘𝐺)    ⇒   ⊢ 0 = (0g‘𝑊)
Theorem	zlm1 31920	Unit of a ℤ-module (if present). (Contributed by Thierry Arnoux, 8-Nov-2017.)
⊢ 𝑊 = (ℤMod‘𝐺)    &   ⊢ 1 = (1r‘𝐺)    ⇒   ⊢ 1 = (1r‘𝑊)
Theorem	zlmds 31921	Distance in a ℤ-module (if present). (Contributed by Thierry Arnoux, 8-Nov-2017.) (Proof shortened by AV, 11-Nov-2024.)
⊢ 𝑊 = (ℤMod‘𝐺)    &   ⊢ 𝐷 = (dist‘𝐺)    ⇒   ⊢ (𝐺 ∈ 𝑉 → 𝐷 = (dist‘𝑊))
Theorem	zlmdsOLD 31922	Obsolete proof of zlmds 31921 as of 11-Nov-2024. Distance in a ℤ -module (if present). (Contributed by Thierry Arnoux, 8-Nov-2017.) (Proof modification is discouraged.) (New usage is discouraged.)
⊢ 𝑊 = (ℤMod‘𝐺)    &   ⊢ 𝐷 = (dist‘𝐺)    ⇒   ⊢ (𝐺 ∈ 𝑉 → 𝐷 = (dist‘𝑊))
Theorem	zlmtset 31923	Topology in a ℤ-module (if present). (Contributed by Thierry Arnoux, 8-Nov-2017.) (Proof shortened by AV, 12-Nov-2024.)
⊢ 𝑊 = (ℤMod‘𝐺)    &   ⊢ 𝐽 = (TopSet‘𝐺)    ⇒   ⊢ (𝐺 ∈ 𝑉 → 𝐽 = (TopSet‘𝑊))
Theorem	zlmtsetOLD 31924	Obsolete proof of zlmtset 31923 as of 11-Nov-2024. Topology in a ℤ -module (if present). (Contributed by Thierry Arnoux, 8-Nov-2017.) (Proof modification is discouraged.) (New usage is discouraged.)
⊢ 𝑊 = (ℤMod‘𝐺)    &   ⊢ 𝐽 = (TopSet‘𝐺)    ⇒   ⊢ (𝐺 ∈ 𝑉 → 𝐽 = (TopSet‘𝑊))
Theorem	zlmnm 31925	Norm of a ℤ-module (if present). (Contributed by Thierry Arnoux, 8-Nov-2017.)
⊢ 𝑊 = (ℤMod‘𝐺)    &   ⊢ 𝑁 = (norm‘𝐺)    ⇒   ⊢ (𝐺 ∈ 𝑉 → 𝑁 = (norm‘𝑊))
Theorem	zhmnrg 31926	The ℤ-module built from a normed ring is also a normed ring. (Contributed by Thierry Arnoux, 8-Nov-2017.)
⊢ 𝑊 = (ℤMod‘𝐺)    ⇒   ⊢ (𝐺 ∈ NrmRing → 𝑊 ∈ NrmRing)
Theorem	nmmulg 31927	The norm of a group product, provided the ℤ-module is normed. (Contributed by Thierry Arnoux, 8-Nov-2017.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑁 = (norm‘𝑅)    &   ⊢ 𝑍 = (ℤMod‘𝑅)    &   ⊢ · = (.g‘𝑅)    ⇒   ⊢ ((𝑍 ∈ NrmMod ∧ 𝑀 ∈ ℤ ∧ 𝑋 ∈ 𝐵) → (𝑁‘(𝑀 · 𝑋)) = ((abs‘𝑀) · (𝑁‘𝑋)))
Theorem	zrhnm 31928	The norm of the image by ℤRHom of an integer in a normed ring. (Contributed by Thierry Arnoux, 8-Nov-2017.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑁 = (norm‘𝑅)    &   ⊢ 𝑍 = (ℤMod‘𝑅)    &   ⊢ 𝐿 = (ℤRHom‘𝑅)    ⇒   ⊢ (((𝑍 ∈ NrmMod ∧ 𝑍 ∈ NrmRing ∧ 𝑅 ∈ NzRing) ∧ 𝑀 ∈ ℤ) → (𝑁‘(𝐿‘𝑀)) = (abs‘𝑀))
Theorem	cnzh 31929	The ℤ-module of ℂ is a normed module. (Contributed by Thierry Arnoux, 25-Feb-2018.)
⊢ (ℤMod‘ℂfld) ∈ NrmMod
Theorem	rezh 31930	The ℤ-module of ℝ is a normed module. (Contributed by Thierry Arnoux, 14-Feb-2018.)
⊢ (ℤMod‘ℝfld) ∈ NrmMod
20.3.14.3  Canonical embedding of the field of the rational numbers into a division ring
Syntax	cqqh 31931	Map the rationals into a field.
class ℚHom
Definition	df-qqh 31932*	Define the canonical homomorphism from the rationals into any field. (Contributed by Mario Carneiro, 22-Oct-2017.) (Revised by Thierry Arnoux, 23-Oct-2017.)
⊢ ℚHom = (𝑟 ∈ V ↦ ran (𝑥 ∈ ℤ, 𝑦 ∈ (◡(ℤRHom‘𝑟) “ (Unit‘𝑟)) ↦ ⟨(𝑥 / 𝑦), (((ℤRHom‘𝑟)‘𝑥)(/r‘𝑟)((ℤRHom‘𝑟)‘𝑦))⟩))
Theorem	qqhval 31933*	Value of the canonical homormorphism from the rational number to a field. (Contributed by Thierry Arnoux, 22-Oct-2017.)
⊢ / = (/r‘𝑅)    &   ⊢ 1 = (1r‘𝑅)    &   ⊢ 𝐿 = (ℤRHom‘𝑅)    ⇒   ⊢ (𝑅 ∈ V → (ℚHom‘𝑅) = ran (𝑥 ∈ ℤ, 𝑦 ∈ (◡𝐿 “ (Unit‘𝑅)) ↦ ⟨(𝑥 / 𝑦), ((𝐿‘𝑥) / (𝐿‘𝑦))⟩))
Theorem	zrhf1ker 31934	The kernel of the homomorphism from the integers to a ring, if it is injective. (Contributed by Thierry Arnoux, 26-Oct-2017.) (Revised by Thierry Arnoux, 23-May-2023.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝐿 = (ℤRHom‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    ⇒   ⊢ (𝑅 ∈ Ring → (𝐿:ℤ–1-1→𝐵 ↔ (◡𝐿 “ { 0 }) = {0}))
Theorem	zrhchr 31935	The kernel of the homomorphism from the integers to a ring is injective if and only if the ring has characteristic 0 . (Contributed by Thierry Arnoux, 8-Nov-2017.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝐿 = (ℤRHom‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    ⇒   ⊢ (𝑅 ∈ Ring → ((chr‘𝑅) = 0 ↔ 𝐿:ℤ–1-1→𝐵))
Theorem	zrhker 31936	The kernel of the homomorphism from the integers to a ring with characteristic 0. (Contributed by Thierry Arnoux, 8-Nov-2017.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝐿 = (ℤRHom‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    ⇒   ⊢ (𝑅 ∈ Ring → ((chr‘𝑅) = 0 ↔ (◡𝐿 “ { 0 }) = {0}))
Theorem	zrhunitpreima 31937	The preimage by ℤRHom of the unit of a division ring is (ℤ ∖ {0}). (Contributed by Thierry Arnoux, 22-Oct-2017.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝐿 = (ℤRHom‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    ⇒   ⊢ ((𝑅 ∈ DivRing ∧ (chr‘𝑅) = 0) → (◡𝐿 “ (Unit‘𝑅)) = (ℤ ∖ {0}))
Theorem	elzrhunit 31938	Condition for the image by ℤRHom to be a unit. (Contributed by Thierry Arnoux, 30-Oct-2017.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝐿 = (ℤRHom‘𝑅)    &   ⊢ 0 = (0g‘𝑅)    ⇒   ⊢ (((𝑅 ∈ DivRing ∧ (chr‘𝑅) = 0) ∧ (𝑀 ∈ ℤ ∧ 𝑀 ≠ 0)) → (𝐿‘𝑀) ∈ (Unit‘𝑅))
Theorem	elzdif0 31939	Lemma for qqhval2 31941. (Contributed by Thierry Arnoux, 29-Oct-2017.)
⊢ (𝑀 ∈ (ℤ ∖ {0}) → (𝑀 ∈ ℕ ∨ -𝑀 ∈ ℕ))
Theorem	qqhval2lem 31940	Lemma for qqhval2 31941. (Contributed by Thierry Arnoux, 29-Oct-2017.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ / = (/r‘𝑅)    &   ⊢ 𝐿 = (ℤRHom‘𝑅)    ⇒   ⊢ (((𝑅 ∈ DivRing ∧ (chr‘𝑅) = 0) ∧ (𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ ∧ 𝑌 ≠ 0)) → ((𝐿‘(numer‘(𝑋 / 𝑌))) / (𝐿‘(denom‘(𝑋 / 𝑌)))) = ((𝐿‘𝑋) / (𝐿‘𝑌)))
Theorem	qqhval2 31941*	Value of the canonical homormorphism from the rational number when the target ring is a division ring. (Contributed by Thierry Arnoux, 26-Oct-2017.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ / = (/r‘𝑅)    &   ⊢ 𝐿 = (ℤRHom‘𝑅)    ⇒   ⊢ ((𝑅 ∈ DivRing ∧ (chr‘𝑅) = 0) → (ℚHom‘𝑅) = (𝑞 ∈ ℚ ↦ ((𝐿‘(numer‘𝑞)) / (𝐿‘(denom‘𝑞)))))
Theorem	qqhvval 31942	Value of the canonical homormorphism from the rational number when the target ring is a division ring. (Contributed by Thierry Arnoux, 30-Oct-2017.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ / = (/r‘𝑅)    &   ⊢ 𝐿 = (ℤRHom‘𝑅)    ⇒   ⊢ (((𝑅 ∈ DivRing ∧ (chr‘𝑅) = 0) ∧ 𝑄 ∈ ℚ) → ((ℚHom‘𝑅)‘𝑄) = ((𝐿‘(numer‘𝑄)) / (𝐿‘(denom‘𝑄))))
Theorem	qqh0 31943	The image of 0 by the ℚHom homomorphism is the ring's zero. (Contributed by Thierry Arnoux, 22-Oct-2017.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ / = (/r‘𝑅)    &   ⊢ 𝐿 = (ℤRHom‘𝑅)    ⇒   ⊢ ((𝑅 ∈ DivRing ∧ (chr‘𝑅) = 0) → ((ℚHom‘𝑅)‘0) = (0g‘𝑅))
Theorem	qqh1 31944	The image of 1 by the ℚHom homomorphism is the ring's unit. (Contributed by Thierry Arnoux, 22-Oct-2017.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ / = (/r‘𝑅)    &   ⊢ 𝐿 = (ℤRHom‘𝑅)    ⇒   ⊢ ((𝑅 ∈ DivRing ∧ (chr‘𝑅) = 0) → ((ℚHom‘𝑅)‘1) = (1r‘𝑅))
Theorem	qqhf 31945	ℚHom as a function. (Contributed by Thierry Arnoux, 28-Oct-2017.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ / = (/r‘𝑅)    &   ⊢ 𝐿 = (ℤRHom‘𝑅)    ⇒   ⊢ ((𝑅 ∈ DivRing ∧ (chr‘𝑅) = 0) → (ℚHom‘𝑅):ℚ⟶𝐵)
Theorem	qqhvq 31946	The image of a quotient by the ℚHom homomorphism. (Contributed by Thierry Arnoux, 28-Oct-2017.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ / = (/r‘𝑅)    &   ⊢ 𝐿 = (ℤRHom‘𝑅)    ⇒   ⊢ (((𝑅 ∈ DivRing ∧ (chr‘𝑅) = 0) ∧ (𝑋 ∈ ℤ ∧ 𝑌 ∈ ℤ ∧ 𝑌 ≠ 0)) → ((ℚHom‘𝑅)‘(𝑋 / 𝑌)) = ((𝐿‘𝑋) / (𝐿‘𝑌)))
Theorem	qqhghm 31947	The ℚHom homomorphism is a group homomorphism if the target structure is a division ring. (Contributed by Thierry Arnoux, 9-Nov-2017.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ / = (/r‘𝑅)    &   ⊢ 𝐿 = (ℤRHom‘𝑅)    &   ⊢ 𝑄 = (ℂfld ↾s ℚ)    ⇒   ⊢ ((𝑅 ∈ DivRing ∧ (chr‘𝑅) = 0) → (ℚHom‘𝑅) ∈ (𝑄 GrpHom 𝑅))
Theorem	qqhrhm 31948	The ℚHom homomorphism is a ring homomorphism if the target structure is a field. If the target structure is a division ring, it is a group homomorphism, but not a ring homomorphism, because it does not preserve the ring multiplication operation. (Contributed by Thierry Arnoux, 29-Oct-2017.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ / = (/r‘𝑅)    &   ⊢ 𝐿 = (ℤRHom‘𝑅)    &   ⊢ 𝑄 = (ℂfld ↾s ℚ)    ⇒   ⊢ ((𝑅 ∈ Field ∧ (chr‘𝑅) = 0) → (ℚHom‘𝑅) ∈ (𝑄 RingHom 𝑅))
Theorem	qqhnm 31949	The norm of the image by ℚHom of a rational number in a topological division ring. (Contributed by Thierry Arnoux, 8-Nov-2017.)
⊢ 𝑁 = (norm‘𝑅)    &   ⊢ 𝑍 = (ℤMod‘𝑅)    ⇒   ⊢ (((𝑅 ∈ (NrmRing ∩ DivRing) ∧ 𝑍 ∈ NrmMod ∧ (chr‘𝑅) = 0) ∧ 𝑄 ∈ ℚ) → (𝑁‘((ℚHom‘𝑅)‘𝑄)) = (abs‘𝑄))
Theorem	qqhcn 31950	The ℚHom homomorphism is a continuous function. (Contributed by Thierry Arnoux, 9-Nov-2017.)
⊢ 𝑄 = (ℂfld ↾s ℚ)    &   ⊢ 𝐽 = (TopOpen‘𝑄)    &   ⊢ 𝑍 = (ℤMod‘𝑅)    &   ⊢ 𝐾 = (TopOpen‘𝑅)    ⇒   ⊢ ((𝑅 ∈ (NrmRing ∩ DivRing) ∧ 𝑍 ∈ NrmMod ∧ (chr‘𝑅) = 0) → (ℚHom‘𝑅) ∈ (𝐽 Cn 𝐾))
Theorem	qqhucn 31951	The ℚHom homomorphism is uniformly continuous. (Contributed by Thierry Arnoux, 28-Jan-2018.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝑄 = (ℂfld ↾s ℚ)    &   ⊢ 𝑈 = (UnifSt‘𝑄)    &   ⊢ 𝑉 = (metUnif‘((dist‘𝑅) ↾ (𝐵 × 𝐵)))    &   ⊢ 𝑍 = (ℤMod‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ NrmRing)    &   ⊢ (𝜑 → 𝑅 ∈ DivRing)    &   ⊢ (𝜑 → 𝑍 ∈ NrmMod)    &   ⊢ (𝜑 → (chr‘𝑅) = 0)    ⇒   ⊢ (𝜑 → (ℚHom‘𝑅) ∈ (𝑈 Cnu𝑉))
20.3.14.4  Canonical embedding of the real numbers into a complete ordered field
Syntax	crrh 31952	Map the real numbers into a complete field.
class ℝHom
Syntax	crrext 31953	Extend class notation with the class of extension fields of ℝ.
class ℝExt
Definition	df-rrh 31954	Define the canonical homomorphism from the real numbers to any complete field, as the extension by continuity of the canonical homomorphism from the rational numbers. (Contributed by Mario Carneiro, 22-Oct-2017.) (Revised by Thierry Arnoux, 23-Oct-2017.)
⊢ ℝHom = (𝑟 ∈ V ↦ (((topGen‘ran (,))CnExt(TopOpen‘𝑟))‘(ℚHom‘𝑟)))
Theorem	rrhval 31955	Value of the canonical homormorphism from the real numbers to a complete space. (Contributed by Thierry Arnoux, 2-Nov-2017.)
⊢ 𝐽 = (topGen‘ran (,))    &   ⊢ 𝐾 = (TopOpen‘𝑅)    ⇒   ⊢ (𝑅 ∈ 𝑉 → (ℝHom‘𝑅) = ((𝐽CnExt𝐾)‘(ℚHom‘𝑅)))
Theorem	rrhcn 31956	If the topology of 𝑅 is Hausdorff, and 𝑅 is a complete uniform space, then the canonical homomorphism from the real numbers to 𝑅 is continuous. (Contributed by Thierry Arnoux, 17-Jan-2018.)
⊢ 𝐷 = ((dist‘𝑅) ↾ (𝐵 × 𝐵))    &   ⊢ 𝐽 = (topGen‘ran (,))    &   ⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝐾 = (TopOpen‘𝑅)    &   ⊢ 𝑍 = (ℤMod‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ DivRing)    &   ⊢ (𝜑 → 𝑅 ∈ NrmRing)    &   ⊢ (𝜑 → 𝑍 ∈ NrmMod)    &   ⊢ (𝜑 → (chr‘𝑅) = 0)    &   ⊢ (𝜑 → 𝑅 ∈ CUnifSp)    &   ⊢ (𝜑 → (UnifSt‘𝑅) = (metUnif‘𝐷))    ⇒   ⊢ (𝜑 → (ℝHom‘𝑅) ∈ (𝐽 Cn 𝐾))
Theorem	rrhf 31957	If the topology of 𝑅 is Hausdorff, Cauchy sequences have at most one limit, i.e. the canonical homomorphism of ℝ into 𝑅 is a function. (Contributed by Thierry Arnoux, 2-Nov-2017.)
⊢ 𝐷 = ((dist‘𝑅) ↾ (𝐵 × 𝐵))    &   ⊢ 𝐽 = (topGen‘ran (,))    &   ⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝐾 = (TopOpen‘𝑅)    &   ⊢ 𝑍 = (ℤMod‘𝑅)    &   ⊢ (𝜑 → 𝑅 ∈ DivRing)    &   ⊢ (𝜑 → 𝑅 ∈ NrmRing)    &   ⊢ (𝜑 → 𝑍 ∈ NrmMod)    &   ⊢ (𝜑 → (chr‘𝑅) = 0)    &   ⊢ (𝜑 → 𝑅 ∈ CUnifSp)    &   ⊢ (𝜑 → (UnifSt‘𝑅) = (metUnif‘𝐷))    ⇒   ⊢ (𝜑 → (ℝHom‘𝑅):ℝ⟶𝐵)
Definition	df-rrext 31958	Define the class of extensions of ℝ. This is a shorthand for listing the necessary conditions for a structure to admit a canonical embedding of ℝ into it. Interestingly, this is not coming from a mathematical reference, but was from the necessary conditions to build the embedding at each step (ℤ, ℚ and ℝ). It would be interesting see if this is formally treated in the literature. See isrrext 31959 for a better readable version. (Contributed by Thierry Arnoux, 2-May-2018.)
⊢ ℝExt = {𝑟 ∈ (NrmRing ∩ DivRing) ∣ (((ℤMod‘𝑟) ∈ NrmMod ∧ (chr‘𝑟) = 0) ∧ (𝑟 ∈ CUnifSp ∧ (UnifSt‘𝑟) = (metUnif‘((dist‘𝑟) ↾ ((Base‘𝑟) × (Base‘𝑟))))))}
Theorem	isrrext 31959	Express the property "𝑅 is an extension of ℝ". (Contributed by Thierry Arnoux, 2-May-2018.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝐷 = ((dist‘𝑅) ↾ (𝐵 × 𝐵))    &   ⊢ 𝑍 = (ℤMod‘𝑅)    ⇒   ⊢ (𝑅 ∈ ℝExt ↔ ((𝑅 ∈ NrmRing ∧ 𝑅 ∈ DivRing) ∧ (𝑍 ∈ NrmMod ∧ (chr‘𝑅) = 0) ∧ (𝑅 ∈ CUnifSp ∧ (UnifSt‘𝑅) = (metUnif‘𝐷))))
Theorem	rrextnrg 31960	An extension of ℝ is a normed ring. (Contributed by Thierry Arnoux, 2-May-2018.)
⊢ (𝑅 ∈ ℝExt → 𝑅 ∈ NrmRing)
Theorem	rrextdrg 31961	An extension of ℝ is a division ring. (Contributed by Thierry Arnoux, 2-May-2018.)
⊢ (𝑅 ∈ ℝExt → 𝑅 ∈ DivRing)
Theorem	rrextnlm 31962	The norm of an extension of ℝ is absolutely homogeneous. (Contributed by Thierry Arnoux, 2-May-2018.)
⊢ 𝑍 = (ℤMod‘𝑅)    ⇒   ⊢ (𝑅 ∈ ℝExt → 𝑍 ∈ NrmMod)
Theorem	rrextchr 31963	The ring characteristic of an extension of ℝ is zero. (Contributed by Thierry Arnoux, 2-May-2018.)
⊢ (𝑅 ∈ ℝExt → (chr‘𝑅) = 0)
Theorem	rrextcusp 31964	An extension of ℝ is a complete uniform space. (Contributed by Thierry Arnoux, 2-May-2018.)
⊢ (𝑅 ∈ ℝExt → 𝑅 ∈ CUnifSp)
Theorem	rrexttps 31965	An extension of ℝ is a topological space. (Contributed by Thierry Arnoux, 7-Sep-2018.)
⊢ (𝑅 ∈ ℝExt → 𝑅 ∈ TopSp)
Theorem	rrexthaus 31966	The topology of an extension of ℝ is Hausdorff. (Contributed by Thierry Arnoux, 7-Sep-2018.)
⊢ 𝐾 = (TopOpen‘𝑅)    ⇒   ⊢ (𝑅 ∈ ℝExt → 𝐾 ∈ Haus)
Theorem	rrextust 31967	The uniformity of an extension of ℝ is the uniformity generated by its distance. (Contributed by Thierry Arnoux, 2-May-2018.)
⊢ 𝐵 = (Base‘𝑅)    &   ⊢ 𝐷 = ((dist‘𝑅) ↾ (𝐵 × 𝐵))    ⇒   ⊢ (𝑅 ∈ ℝExt → (UnifSt‘𝑅) = (metUnif‘𝐷))
Theorem	rerrext 31968	The field of the real numbers is an extension of the real numbers. (Contributed by Thierry Arnoux, 2-May-2018.)
⊢ ℝfld ∈ ℝExt
Theorem	cnrrext 31969	The field of the complex numbers is an extension of the real numbers. (Contributed by Thierry Arnoux, 2-May-2018.)
⊢ ℂfld ∈ ℝExt
Theorem	qqtopn 31970	The topology of the field of the rational numbers. (Contributed by Thierry Arnoux, 29-Aug-2020.)
⊢ ((TopOpen‘ℝfld) ↾t ℚ) = (TopOpen‘(ℂfld ↾s ℚ))
Theorem	rrhfe 31971	If 𝑅 is an extension of ℝ, then the canonical homomorphism of ℝ into 𝑅 is a function. (Contributed by Thierry Arnoux, 2-May-2018.)
⊢ 𝐵 = (Base‘𝑅)    ⇒   ⊢ (𝑅 ∈ ℝExt → (ℝHom‘𝑅):ℝ⟶𝐵)
Theorem	rrhcne 31972	If 𝑅 is an extension of ℝ, then the canonical homomorphism of ℝ into 𝑅 is continuous. (Contributed by Thierry Arnoux, 2-May-2018.)
⊢ 𝐽 = (topGen‘ran (,))    &   ⊢ 𝐾 = (TopOpen‘𝑅)    ⇒   ⊢ (𝑅 ∈ ℝExt → (ℝHom‘𝑅) ∈ (𝐽 Cn 𝐾))
Theorem	rrhqima 31973	The ℝHom homomorphism leaves rational numbers unchanged. (Contributed by Thierry Arnoux, 27-Mar-2018.)
⊢ ((𝑅 ∈ ℝExt ∧ 𝑄 ∈ ℚ) → ((ℝHom‘𝑅)‘𝑄) = ((ℚHom‘𝑅)‘𝑄))
Theorem	rrh0 31974	The image of 0 by the ℝHom homomorphism is the ring's zero. (Contributed by Thierry Arnoux, 22-Oct-2017.)
⊢ (𝑅 ∈ ℝExt → ((ℝHom‘𝑅)‘0) = (0g‘𝑅))
20.3.14.5  Embedding from the extended real numbers into a complete lattice
Syntax	cxrh 31975	Map the extended real numbers into a complete lattice.
class ℝ*Hom
Definition	df-xrh 31976*	Define an embedding from the extended real number into a complete lattice. (Contributed by Thierry Arnoux, 19-Feb-2018.)
⊢ ℝ*Hom = (𝑟 ∈ V ↦ (𝑥 ∈ ℝ* ↦ if(𝑥 ∈ ℝ, ((ℝHom‘𝑟)‘𝑥), if(𝑥 = +∞, ((lub‘𝑟)‘((ℝHom‘𝑟) “ ℝ)), ((glb‘𝑟)‘((ℝHom‘𝑟) “ ℝ))))))
Theorem	xrhval 31977*	The value of the embedding from the extended real numbers into a complete lattice. (Contributed by Thierry Arnoux, 19-Feb-2018.)
⊢ 𝐵 = ((ℝHom‘𝑅) “ ℝ)    &   ⊢ 𝐿 = (glb‘𝑅)    &   ⊢ 𝑈 = (lub‘𝑅)    ⇒   ⊢ (𝑅 ∈ 𝑉 → (ℝ*Hom‘𝑅) = (𝑥 ∈ ℝ* ↦ if(𝑥 ∈ ℝ, ((ℝHom‘𝑅)‘𝑥), if(𝑥 = +∞, (𝑈‘𝐵), (𝐿‘𝐵)))))
20.3.14.6  Canonical embeddings into the ordered field of the real numbers
Theorem	zrhre 31978	The ℤRHom homomorphism for the real number structure is the identity. (Contributed by Thierry Arnoux, 31-Oct-2017.)
⊢ (ℤRHom‘ℝfld) = ( I ↾ ℤ)
Theorem	qqhre 31979	The ℚHom homomorphism for the real number structure is the identity. (Contributed by Thierry Arnoux, 31-Oct-2017.)
⊢ (ℚHom‘ℝfld) = ( I ↾ ℚ)
Theorem	rrhre 31980	The ℝHom homomorphism for the real numbers structure is the identity. (Contributed by Thierry Arnoux, 22-Oct-2017.)
⊢ (ℝHom‘ℝfld) = ( I ↾ ℝ)
20.3.14.7  Topological Manifolds Found this and was curious about how manifolds would be expressed in set.mm: https://mathoverflow.net/questions/336367/real-manifolds-in-a-theorem-prover This chapter proposes to define first manifold topologies, which characterize topological manifolds, and then to extend the structure with presentations, i.e., equivalence classes of atlases for a given topological space. We suggest to use the extensible structures to define the "topological space" aspect of topological manifolds, and then extend it with charts/presentations.
Syntax	cmntop 31981	The class of n-manifold topologies.
class ManTop
Definition	df-mntop 31982*	Define the class of 𝑁-manifold topologies, as second countable Hausdorff topologies locally homeomorphic to a ball of the Euclidean space of dimension 𝑁. (Contributed by Thierry Arnoux, 22-Dec-2019.)
⊢ ManTop = {⟨𝑛, 𝑗⟩ ∣ (𝑛 ∈ ℕ0 ∧ (𝑗 ∈ 2ndω ∧ 𝑗 ∈ Haus ∧ 𝑗 ∈ Locally [(TopOpen‘(𝔼hil‘𝑛))] ≃ ))}
Theorem	relmntop 31983	Manifold is a relation. (Contributed by Thierry Arnoux, 28-Dec-2019.)
⊢ Rel ManTop
Theorem	ismntoplly 31984	Property of being a manifold. (Contributed by Thierry Arnoux, 28-Dec-2019.)
⊢ ((𝑁 ∈ ℕ0 ∧ 𝐽 ∈ 𝑉) → (𝑁ManTop𝐽 ↔ (𝐽 ∈ 2ndω ∧ 𝐽 ∈ Haus ∧ 𝐽 ∈ Locally [(TopOpen‘(𝔼hil‘𝑁))] ≃ )))
Theorem	ismntop 31985*	Property of being a manifold. (Contributed by Thierry Arnoux, 5-Jan-2020.)
⊢ ((𝑁 ∈ ℕ0 ∧ 𝐽 ∈ 𝑉) → (𝑁ManTop𝐽 ↔ (𝐽 ∈ 2ndω ∧ 𝐽 ∈ Haus ∧ ∀𝑥 ∈ 𝐽 ∀𝑦 ∈ 𝑥 ∃𝑢 ∈ (𝐽 ∩ 𝒫 𝑥)(𝑦 ∈ 𝑢 ∧ (𝐽 ↾t 𝑢) ≃ (TopOpen‘(𝔼hil‘𝑁))))))
20.3.15  Real and complex functions
20.3.15.1  Integer powers - misc. additions
Theorem	nexple 31986	A lower bound for an exponentiation. (Contributed by Thierry Arnoux, 19-Aug-2017.)
⊢ ((𝐴 ∈ ℕ0 ∧ 𝐵 ∈ ℝ ∧ 2 ≤ 𝐵) → 𝐴 ≤ (𝐵↑𝐴))
20.3.15.2  Indicator Functions
Syntax	cind 31987	Extend class notation with the indicator function generator.
class 𝟭
Definition	df-ind 31988*	Define the indicator function generator. (Contributed by Thierry Arnoux, 20-Jan-2017.)
⊢ 𝟭 = (𝑜 ∈ V ↦ (𝑎 ∈ 𝒫 𝑜 ↦ (𝑥 ∈ 𝑜 ↦ if(𝑥 ∈ 𝑎, 1, 0))))
Theorem	indv 31989*	Value of the indicator function generator with domain 𝑂. (Contributed by Thierry Arnoux, 23-Aug-2017.)
⊢ (𝑂 ∈ 𝑉 → (𝟭‘𝑂) = (𝑎 ∈ 𝒫 𝑂 ↦ (𝑥 ∈ 𝑂 ↦ if(𝑥 ∈ 𝑎, 1, 0))))
Theorem	indval 31990*	Value of the indicator function generator for a set 𝐴 and a domain 𝑂. (Contributed by Thierry Arnoux, 2-Feb-2017.)
⊢ ((𝑂 ∈ 𝑉 ∧ 𝐴 ⊆ 𝑂) → ((𝟭‘𝑂)‘𝐴) = (𝑥 ∈ 𝑂 ↦ if(𝑥 ∈ 𝐴, 1, 0)))
Theorem	indval2 31991	Alternate value of the indicator function generator. (Contributed by Thierry Arnoux, 2-Feb-2017.)
⊢ ((𝑂 ∈ 𝑉 ∧ 𝐴 ⊆ 𝑂) → ((𝟭‘𝑂)‘𝐴) = ((𝐴 × {1}) ∪ ((𝑂 ∖ 𝐴) × {0})))
Theorem	indf 31992	An indicator function as a function with domain and codomain. (Contributed by Thierry Arnoux, 13-Aug-2017.)
⊢ ((𝑂 ∈ 𝑉 ∧ 𝐴 ⊆ 𝑂) → ((𝟭‘𝑂)‘𝐴):𝑂⟶{0, 1})
Theorem	indfval 31993	Value of the indicator function. (Contributed by Thierry Arnoux, 13-Aug-2017.)
⊢ ((𝑂 ∈ 𝑉 ∧ 𝐴 ⊆ 𝑂 ∧ 𝑋 ∈ 𝑂) → (((𝟭‘𝑂)‘𝐴)‘𝑋) = if(𝑋 ∈ 𝐴, 1, 0))
Theorem	ind1 31994	Value of the indicator function where it is 1. (Contributed by Thierry Arnoux, 14-Aug-2017.)
⊢ ((𝑂 ∈ 𝑉 ∧ 𝐴 ⊆ 𝑂 ∧ 𝑋 ∈ 𝐴) → (((𝟭‘𝑂)‘𝐴)‘𝑋) = 1)
Theorem	ind0 31995	Value of the indicator function where it is 0. (Contributed by Thierry Arnoux, 14-Aug-2017.)
⊢ ((𝑂 ∈ 𝑉 ∧ 𝐴 ⊆ 𝑂 ∧ 𝑋 ∈ (𝑂 ∖ 𝐴)) → (((𝟭‘𝑂)‘𝐴)‘𝑋) = 0)
Theorem	ind1a 31996	Value of the indicator function where it is 1. (Contributed by Thierry Arnoux, 22-Aug-2017.)
⊢ ((𝑂 ∈ 𝑉 ∧ 𝐴 ⊆ 𝑂 ∧ 𝑋 ∈ 𝑂) → ((((𝟭‘𝑂)‘𝐴)‘𝑋) = 1 ↔ 𝑋 ∈ 𝐴))
Theorem	indpi1 31997	Preimage of the singleton {1} by the indicator function. See i1f1lem 24862. (Contributed by Thierry Arnoux, 21-Aug-2017.)
⊢ ((𝑂 ∈ 𝑉 ∧ 𝐴 ⊆ 𝑂) → (◡((𝟭‘𝑂)‘𝐴) “ {1}) = 𝐴)
Theorem	indsum 31998*	Finite sum of a product with the indicator function / Cartesian product with the indicator function. (Contributed by Thierry Arnoux, 14-Aug-2017.)
⊢ (𝜑 → 𝑂 ∈ Fin)    &   ⊢ (𝜑 → 𝐴 ⊆ 𝑂)    &   ⊢ ((𝜑 ∧ 𝑥 ∈ 𝑂) → 𝐵 ∈ ℂ)    ⇒   ⊢ (𝜑 → Σ𝑥 ∈ 𝑂 ((((𝟭‘𝑂)‘𝐴)‘𝑥) · 𝐵) = Σ𝑥 ∈ 𝐴 𝐵)
Theorem	indsumin 31999*	Finite sum of a product with the indicator function / Cartesian product with the indicator function. (Contributed by Thierry Arnoux, 11-Dec-2021.)
⊢ (𝜑 → 𝑂 ∈ 𝑉)    &   ⊢ (𝜑 → 𝐴 ∈ Fin)    &   ⊢ (𝜑 → 𝐴 ⊆ 𝑂)    &   ⊢ (𝜑 → 𝐵 ⊆ 𝑂)    &   ⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → 𝐶 ∈ ℂ)    ⇒   ⊢ (𝜑 → Σ𝑘 ∈ 𝐴 ((((𝟭‘𝑂)‘𝐵)‘𝑘) · 𝐶) = Σ𝑘 ∈ (𝐴 ∩ 𝐵)𝐶)
Theorem	prodindf 32000*	The product of indicators is one if and only if all values are in the set. (Contributed by Thierry Arnoux, 11-Dec-2021.)
⊢ (𝜑 → 𝑂 ∈ 𝑉)    &   ⊢ (𝜑 → 𝐴 ∈ Fin)    &   ⊢ (𝜑 → 𝐵 ⊆ 𝑂)    &   ⊢ (𝜑 → 𝐹:𝐴⟶𝑂)    ⇒   ⊢ (𝜑 → ∏𝑘 ∈ 𝐴 (((𝟭‘𝑂)‘𝐵)‘(𝐹‘𝑘)) = if(ran 𝐹 ⊆ 𝐵, 1, 0))