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| Type | Label | Description |
|---|---|---|
| Statement | ||
| Theorem | hlprlem 25401 | Lemma for hlpr 25403. (Contributed by Mario Carneiro, 15-Oct-2015.) |
| ⊢ 𝐹 = (Scalar‘𝑊) & ⊢ 𝐾 = (Base‘𝐹) ⇒ ⊢ (𝑊 ∈ ℂHil → (𝐾 ∈ (SubRing‘ℂfld) ∧ (ℂfld ↾s 𝐾) ∈ DivRing ∧ (ℂfld ↾s 𝐾) ∈ CMetSp)) | ||
| Theorem | hlress 25402 | The scalar field of a subcomplex Hilbert space contains ℝ. (Contributed by Mario Carneiro, 8-Oct-2015.) |
| ⊢ 𝐹 = (Scalar‘𝑊) & ⊢ 𝐾 = (Base‘𝐹) ⇒ ⊢ (𝑊 ∈ ℂHil → ℝ ⊆ 𝐾) | ||
| Theorem | hlpr 25403 | The scalar field of a subcomplex Hilbert space is either ℝ or ℂ. (Contributed by Mario Carneiro, 15-Oct-2015.) |
| ⊢ 𝐹 = (Scalar‘𝑊) & ⊢ 𝐾 = (Base‘𝐹) ⇒ ⊢ (𝑊 ∈ ℂHil → 𝐾 ∈ {ℝ, ℂ}) | ||
| Theorem | ishl2 25404 | A Hilbert space is a complete subcomplex pre-Hilbert space over ℝ or ℂ. (Contributed by Mario Carneiro, 15-Oct-2015.) |
| ⊢ 𝐹 = (Scalar‘𝑊) & ⊢ 𝐾 = (Base‘𝐹) ⇒ ⊢ (𝑊 ∈ ℂHil ↔ (𝑊 ∈ CMetSp ∧ 𝑊 ∈ ℂPreHil ∧ 𝐾 ∈ {ℝ, ℂ})) | ||
| Theorem | cphssphl 25405 | A Banach subspace of a subcomplex pre-Hilbert space is a subcomplex Hilbert space. (Contributed by NM, 11-Apr-2008.) (Revised by AV, 25-Sep-2022.) |
| ⊢ 𝑋 = (𝑊 ↾s 𝑈) & ⊢ 𝑆 = (LSubSp‘𝑊) ⇒ ⊢ ((𝑊 ∈ ℂPreHil ∧ 𝑈 ∈ 𝑆 ∧ 𝑋 ∈ Ban) → 𝑋 ∈ ℂHil) | ||
| Theorem | cmslssbn 25406 | A complete linear subspace of a normed vector space is a Banach space. We furthermore have to assume that the field of scalars is complete since this is a requirement in the current definition of Banach spaces df-bn 25370. (Contributed by AV, 8-Oct-2022.) |
| ⊢ 𝑋 = (𝑊 ↾s 𝑈) & ⊢ 𝑆 = (LSubSp‘𝑊) ⇒ ⊢ (((𝑊 ∈ NrmVec ∧ (Scalar‘𝑊) ∈ CMetSp) ∧ (𝑋 ∈ CMetSp ∧ 𝑈 ∈ 𝑆)) → 𝑋 ∈ Ban) | ||
| Theorem | cmscsscms 25407 | A closed subspace of a complete metric space which is also a subcomplex pre-Hilbert space is a complete metric space. Remark: the assumption that the Banach space must be a (subcomplex) pre-Hilbert space is required because the definition of ClSubSp is based on an inner product. If ClSubSp was generalized to arbitrary topological spaces (or at least topological modules), this assumption could be omitted. (Contributed by AV, 8-Oct-2022.) |
| ⊢ 𝑋 = (𝑊 ↾s 𝑈) & ⊢ 𝑆 = (ClSubSp‘𝑊) ⇒ ⊢ (((𝑊 ∈ CMetSp ∧ 𝑊 ∈ ℂPreHil) ∧ 𝑈 ∈ 𝑆) → 𝑋 ∈ CMetSp) | ||
| Theorem | bncssbn 25408 | A closed subspace of a Banach space which is also a subcomplex pre-Hilbert space is a Banach space. Remark: the assumption that the Banach space must be a (subcomplex) pre-Hilbert space is required because the definition of ClSubSp is based on an inner product. If ClSubSp was generalized for arbitrary topological spaces, this assuption could be omitted. (Contributed by AV, 8-Oct-2022.) |
| ⊢ 𝑋 = (𝑊 ↾s 𝑈) & ⊢ 𝑆 = (ClSubSp‘𝑊) ⇒ ⊢ (((𝑊 ∈ Ban ∧ 𝑊 ∈ ℂPreHil) ∧ 𝑈 ∈ 𝑆) → 𝑋 ∈ Ban) | ||
| Theorem | cssbn 25409 | A complete subspace of a normed vector space with a complete scalar field is a Banach space. Remark: In contrast to ClSubSp, a complete subspace is defined by "a linear subspace in which all Cauchy sequences converge to a point in the subspace". This is closer to the original, but deprecated definition Cℋ (df-ch 31240) of closed subspaces of a Hilbert space. It may be superseded by cmslssbn 25406. (Contributed by NM, 10-Apr-2008.) (Revised by AV, 6-Oct-2022.) |
| ⊢ 𝑋 = (𝑊 ↾s 𝑈) & ⊢ 𝑆 = (LSubSp‘𝑊) & ⊢ 𝐷 = ((dist‘𝑊) ↾ (𝑈 × 𝑈)) ⇒ ⊢ (((𝑊 ∈ NrmVec ∧ (Scalar‘𝑊) ∈ CMetSp ∧ 𝑈 ∈ 𝑆) ∧ (Cau‘𝐷) ⊆ dom (⇝𝑡‘(MetOpen‘𝐷))) → 𝑋 ∈ Ban) | ||
| Theorem | csschl 25410 | A complete subspace of a complex pre-Hilbert space is a complex Hilbert space. Remarks: (a) In contrast to ClSubSp, a complete subspace is defined by "a linear subspace in which all Cauchy sequences converge to a point in the subspace". This is closer to the original, but deprecated definition Cℋ (df-ch 31240) of closed subspaces of a Hilbert space. (b) This theorem does not hold for arbitrary subcomplex (pre-)Hilbert spaces, because the scalar field as restriction of the field of the complex numbers need not be closed. (Contributed by NM, 10-Apr-2008.) (Revised by AV, 6-Oct-2022.) |
| ⊢ 𝑋 = (𝑊 ↾s 𝑈) & ⊢ 𝑆 = (LSubSp‘𝑊) & ⊢ 𝐷 = ((dist‘𝑊) ↾ (𝑈 × 𝑈)) & ⊢ (Scalar‘𝑊) = ℂfld ⇒ ⊢ ((𝑊 ∈ ℂPreHil ∧ 𝑈 ∈ 𝑆 ∧ (Cau‘𝐷) ⊆ dom (⇝𝑡‘(MetOpen‘𝐷))) → (𝑋 ∈ ℂHil ∧ (Scalar‘𝑋) = ℂfld)) | ||
| Theorem | cmslsschl 25411 | A complete linear subspace of a subcomplex Hilbert space is a subcomplex Hilbert space. (Contributed by AV, 8-Oct-2022.) |
| ⊢ 𝑋 = (𝑊 ↾s 𝑈) & ⊢ 𝑆 = (LSubSp‘𝑊) ⇒ ⊢ ((𝑊 ∈ ℂHil ∧ 𝑋 ∈ CMetSp ∧ 𝑈 ∈ 𝑆) → 𝑋 ∈ ℂHil) | ||
| Theorem | chlcsschl 25412 | A closed subspace of a subcomplex Hilbert space is a subcomplex Hilbert space. (Contributed by NM, 10-Apr-2008.) (Revised by AV, 8-Oct-2022.) |
| ⊢ 𝑋 = (𝑊 ↾s 𝑈) & ⊢ 𝑆 = (ClSubSp‘𝑊) ⇒ ⊢ ((𝑊 ∈ ℂHil ∧ 𝑈 ∈ 𝑆) → 𝑋 ∈ ℂHil) | ||
| Theorem | retopn 25413 | The topology of the real numbers. (Contributed by Thierry Arnoux, 30-Jun-2019.) |
| ⊢ (topGen‘ran (,)) = (TopOpen‘ℝfld) | ||
| Theorem | recms 25414 | The real numbers form a complete metric space. (Contributed by Thierry Arnoux, 1-Nov-2017.) |
| ⊢ ℝfld ∈ CMetSp | ||
| Theorem | reust 25415 | The Uniform structure of the real numbers. (Contributed by Thierry Arnoux, 14-Feb-2018.) |
| ⊢ (UnifSt‘ℝfld) = (metUnif‘((dist‘ℝfld) ↾ (ℝ × ℝ))) | ||
| Theorem | recusp 25416 | The real numbers form a complete uniform space. (Contributed by Thierry Arnoux, 17-Dec-2017.) |
| ⊢ ℝfld ∈ CUnifSp | ||
| Syntax | crrx 25417 | Extend class notation with generalized real Euclidean spaces. |
| class ℝ^ | ||
| Syntax | cehl 25418 | Extend class notation with real Euclidean spaces. |
| class 𝔼hil | ||
| Definition | df-rrx 25419 | Define the function associating with a set the free real vector space on that set, equipped with the natural inner product and norm. This is the direct sum of copies of the field of real numbers indexed by that set. We call it here a "generalized real Euclidean space", but note that it need not be complete (for instance if the given set is infinite countable). (Contributed by Thierry Arnoux, 16-Jun-2019.) |
| ⊢ ℝ^ = (𝑖 ∈ V ↦ (toℂPreHil‘(ℝfld freeLMod 𝑖))) | ||
| Definition | df-ehl 25420 | Define a function generating the real Euclidean spaces of finite dimension. The case 𝑛 = 0 corresponds to a space of dimension 0, that is, limited to a neutral element (see ehl0 25451). Members of this family of spaces are Hilbert spaces, as shown in - ehlhl . (Contributed by Thierry Arnoux, 16-Jun-2019.) |
| ⊢ 𝔼hil = (𝑛 ∈ ℕ0 ↦ (ℝ^‘(1...𝑛))) | ||
| Theorem | rrxval 25421 | Value of the generalized Euclidean space. (Contributed by Thierry Arnoux, 16-Jun-2019.) |
| ⊢ 𝐻 = (ℝ^‘𝐼) ⇒ ⊢ (𝐼 ∈ 𝑉 → 𝐻 = (toℂPreHil‘(ℝfld freeLMod 𝐼))) | ||
| Theorem | rrxbase 25422* | The base of the generalized real Euclidean space is the set of functions with finite support. (Contributed by Thierry Arnoux, 16-Jun-2019.) (Proof shortened by AV, 22-Jul-2019.) |
| ⊢ 𝐻 = (ℝ^‘𝐼) & ⊢ 𝐵 = (Base‘𝐻) ⇒ ⊢ (𝐼 ∈ 𝑉 → 𝐵 = {𝑓 ∈ (ℝ ↑m 𝐼) ∣ 𝑓 finSupp 0}) | ||
| Theorem | rrxprds 25423 | Expand the definition of the generalized real Euclidean spaces. (Contributed by Thierry Arnoux, 16-Jun-2019.) |
| ⊢ 𝐻 = (ℝ^‘𝐼) & ⊢ 𝐵 = (Base‘𝐻) ⇒ ⊢ (𝐼 ∈ 𝑉 → 𝐻 = (toℂPreHil‘((ℝfldXs(𝐼 × {((subringAlg ‘ℝfld)‘ℝ)})) ↾s 𝐵))) | ||
| Theorem | rrxip 25424* | The inner product of the generalized real Euclidean spaces. (Contributed by Thierry Arnoux, 16-Jun-2019.) |
| ⊢ 𝐻 = (ℝ^‘𝐼) & ⊢ 𝐵 = (Base‘𝐻) ⇒ ⊢ (𝐼 ∈ 𝑉 → (𝑓 ∈ (ℝ ↑m 𝐼), 𝑔 ∈ (ℝ ↑m 𝐼) ↦ (ℝfld Σg (𝑥 ∈ 𝐼 ↦ ((𝑓‘𝑥) · (𝑔‘𝑥))))) = (·𝑖‘𝐻)) | ||
| Theorem | rrxnm 25425* | The norm of the generalized real Euclidean spaces. (Contributed by Thierry Arnoux, 16-Jun-2019.) |
| ⊢ 𝐻 = (ℝ^‘𝐼) & ⊢ 𝐵 = (Base‘𝐻) ⇒ ⊢ (𝐼 ∈ 𝑉 → (𝑓 ∈ 𝐵 ↦ (√‘(ℝfld Σg (𝑥 ∈ 𝐼 ↦ ((𝑓‘𝑥)↑2))))) = (norm‘𝐻)) | ||
| Theorem | rrxcph 25426 | Generalized Euclidean real spaces are subcomplex pre-Hilbert spaces. (Contributed by Thierry Arnoux, 23-Jun-2019.) (Proof shortened by AV, 22-Jul-2019.) |
| ⊢ 𝐻 = (ℝ^‘𝐼) & ⊢ 𝐵 = (Base‘𝐻) ⇒ ⊢ (𝐼 ∈ 𝑉 → 𝐻 ∈ ℂPreHil) | ||
| Theorem | rrxds 25427* | The distance over generalized Euclidean spaces. Compare with df-rrn 37833. (Contributed by Thierry Arnoux, 20-Jun-2019.) (Proof shortened by AV, 20-Jul-2019.) |
| ⊢ 𝐻 = (ℝ^‘𝐼) & ⊢ 𝐵 = (Base‘𝐻) ⇒ ⊢ (𝐼 ∈ 𝑉 → (𝑓 ∈ 𝐵, 𝑔 ∈ 𝐵 ↦ (√‘(ℝfld Σg (𝑥 ∈ 𝐼 ↦ (((𝑓‘𝑥) − (𝑔‘𝑥))↑2))))) = (dist‘𝐻)) | ||
| Theorem | rrxvsca 25428 | The scalar product over generalized Euclidean spaces is the componentwise real number multiplication. (Contributed by Thierry Arnoux, 18-Jan-2023.) |
| ⊢ 𝐻 = (ℝ^‘𝐼) & ⊢ 𝐵 = (Base‘𝐻) & ⊢ ∙ = ( ·𝑠 ‘𝐻) & ⊢ (𝜑 → 𝐼 ∈ 𝑉) & ⊢ (𝜑 → 𝐽 ∈ 𝐼) & ⊢ (𝜑 → 𝐴 ∈ ℝ) & ⊢ (𝜑 → 𝑋 ∈ (Base‘𝐻)) ⇒ ⊢ (𝜑 → ((𝐴 ∙ 𝑋)‘𝐽) = (𝐴 · (𝑋‘𝐽))) | ||
| Theorem | rrxplusgvscavalb 25429* | The result of the addition combined with scalar multiplication in a generalized Euclidean space is defined by its coordinate-wise operations. (Contributed by AV, 21-Jan-2023.) |
| ⊢ 𝐻 = (ℝ^‘𝐼) & ⊢ 𝐵 = (Base‘𝐻) & ⊢ ∙ = ( ·𝑠 ‘𝐻) & ⊢ (𝜑 → 𝐼 ∈ 𝑉) & ⊢ (𝜑 → 𝐴 ∈ ℝ) & ⊢ (𝜑 → 𝑋 ∈ 𝐵) & ⊢ (𝜑 → 𝑌 ∈ 𝐵) & ⊢ (𝜑 → 𝑍 ∈ 𝐵) & ⊢ ✚ = (+g‘𝐻) & ⊢ (𝜑 → 𝐶 ∈ ℝ) ⇒ ⊢ (𝜑 → (𝑍 = ((𝐴 ∙ 𝑋) ✚ (𝐶 ∙ 𝑌)) ↔ ∀𝑖 ∈ 𝐼 (𝑍‘𝑖) = ((𝐴 · (𝑋‘𝑖)) + (𝐶 · (𝑌‘𝑖))))) | ||
| Theorem | rrxsca 25430 | The field of real numbers is the scalar field of the generalized real Euclidean space. (Contributed by AV, 15-Jan-2023.) |
| ⊢ 𝐻 = (ℝ^‘𝐼) ⇒ ⊢ (𝐼 ∈ 𝑉 → (Scalar‘𝐻) = ℝfld) | ||
| Theorem | rrx0 25431 | The zero ("origin") in a generalized real Euclidean space. (Contributed by AV, 11-Feb-2023.) |
| ⊢ 𝐻 = (ℝ^‘𝐼) & ⊢ 0 = (𝐼 × {0}) ⇒ ⊢ (𝐼 ∈ 𝑉 → (0g‘𝐻) = 0 ) | ||
| Theorem | rrx0el 25432 | The zero ("origin") in a generalized real Euclidean space is an element of its base set. (Contributed by AV, 11-Feb-2023.) |
| ⊢ 0 = (𝐼 × {0}) & ⊢ 𝑃 = (ℝ ↑m 𝐼) ⇒ ⊢ (𝐼 ∈ 𝑉 → 0 ∈ 𝑃) | ||
| Theorem | csbren 25433* | Cauchy-Schwarz-Bunjakovsky inequality for R^n. (Contributed by Jeff Madsen, 2-Sep-2009.) (Revised by Mario Carneiro, 4-Jun-2014.) |
| ⊢ (𝜑 → 𝐴 ∈ Fin) & ⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → 𝐵 ∈ ℝ) & ⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → 𝐶 ∈ ℝ) ⇒ ⊢ (𝜑 → (Σ𝑘 ∈ 𝐴 (𝐵 · 𝐶)↑2) ≤ (Σ𝑘 ∈ 𝐴 (𝐵↑2) · Σ𝑘 ∈ 𝐴 (𝐶↑2))) | ||
| Theorem | trirn 25434* | Triangle inequality in R^n. (Contributed by Jeff Madsen, 2-Sep-2009.) (Revised by Mario Carneiro, 4-Jun-2014.) |
| ⊢ (𝜑 → 𝐴 ∈ Fin) & ⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → 𝐵 ∈ ℝ) & ⊢ ((𝜑 ∧ 𝑘 ∈ 𝐴) → 𝐶 ∈ ℝ) ⇒ ⊢ (𝜑 → (√‘Σ𝑘 ∈ 𝐴 ((𝐵 + 𝐶)↑2)) ≤ ((√‘Σ𝑘 ∈ 𝐴 (𝐵↑2)) + (√‘Σ𝑘 ∈ 𝐴 (𝐶↑2)))) | ||
| Theorem | rrxf 25435* | Euclidean vectors as functions. (Contributed by Thierry Arnoux, 7-Jul-2019.) |
| ⊢ 𝑋 = {ℎ ∈ (ℝ ↑m 𝐼) ∣ ℎ finSupp 0} & ⊢ (𝜑 → 𝐹 ∈ 𝑋) ⇒ ⊢ (𝜑 → 𝐹:𝐼⟶ℝ) | ||
| Theorem | rrxfsupp 25436* | Euclidean vectors are of finite support. (Contributed by Thierry Arnoux, 7-Jul-2019.) |
| ⊢ 𝑋 = {ℎ ∈ (ℝ ↑m 𝐼) ∣ ℎ finSupp 0} & ⊢ (𝜑 → 𝐹 ∈ 𝑋) ⇒ ⊢ (𝜑 → (𝐹 supp 0) ∈ Fin) | ||
| Theorem | rrxsuppss 25437* | Support of Euclidean vectors. (Contributed by Thierry Arnoux, 7-Jul-2019.) |
| ⊢ 𝑋 = {ℎ ∈ (ℝ ↑m 𝐼) ∣ ℎ finSupp 0} & ⊢ (𝜑 → 𝐹 ∈ 𝑋) ⇒ ⊢ (𝜑 → (𝐹 supp 0) ⊆ 𝐼) | ||
| Theorem | rrxmvallem 25438* | Support of the function used for building the distance . (Contributed by Thierry Arnoux, 30-Jun-2019.) |
| ⊢ 𝑋 = {ℎ ∈ (ℝ ↑m 𝐼) ∣ ℎ finSupp 0} ⇒ ⊢ ((𝐼 ∈ 𝑉 ∧ 𝐹 ∈ 𝑋 ∧ 𝐺 ∈ 𝑋) → ((𝑘 ∈ 𝐼 ↦ (((𝐹‘𝑘) − (𝐺‘𝑘))↑2)) supp 0) ⊆ ((𝐹 supp 0) ∪ (𝐺 supp 0))) | ||
| Theorem | rrxmval 25439* | The value of the Euclidean metric. Compare with rrnmval 37835. (Contributed by Thierry Arnoux, 30-Jun-2019.) |
| ⊢ 𝑋 = {ℎ ∈ (ℝ ↑m 𝐼) ∣ ℎ finSupp 0} & ⊢ 𝐷 = (dist‘(ℝ^‘𝐼)) ⇒ ⊢ ((𝐼 ∈ 𝑉 ∧ 𝐹 ∈ 𝑋 ∧ 𝐺 ∈ 𝑋) → (𝐹𝐷𝐺) = (√‘Σ𝑘 ∈ ((𝐹 supp 0) ∪ (𝐺 supp 0))(((𝐹‘𝑘) − (𝐺‘𝑘))↑2))) | ||
| Theorem | rrxmfval 25440* | The value of the Euclidean metric. Compare with rrnval 37834. (Contributed by Thierry Arnoux, 30-Jun-2019.) |
| ⊢ 𝑋 = {ℎ ∈ (ℝ ↑m 𝐼) ∣ ℎ finSupp 0} & ⊢ 𝐷 = (dist‘(ℝ^‘𝐼)) ⇒ ⊢ (𝐼 ∈ 𝑉 → 𝐷 = (𝑓 ∈ 𝑋, 𝑔 ∈ 𝑋 ↦ (√‘Σ𝑘 ∈ ((𝑓 supp 0) ∪ (𝑔 supp 0))(((𝑓‘𝑘) − (𝑔‘𝑘))↑2)))) | ||
| Theorem | rrxmetlem 25441* | Lemma for rrxmet 25442. (Contributed by Thierry Arnoux, 5-Jul-2019.) |
| ⊢ 𝑋 = {ℎ ∈ (ℝ ↑m 𝐼) ∣ ℎ finSupp 0} & ⊢ 𝐷 = (dist‘(ℝ^‘𝐼)) & ⊢ (𝜑 → 𝐼 ∈ 𝑉) & ⊢ (𝜑 → 𝐹 ∈ 𝑋) & ⊢ (𝜑 → 𝐺 ∈ 𝑋) & ⊢ (𝜑 → 𝐴 ⊆ 𝐼) & ⊢ (𝜑 → 𝐴 ∈ Fin) & ⊢ (𝜑 → ((𝐹 supp 0) ∪ (𝐺 supp 0)) ⊆ 𝐴) ⇒ ⊢ (𝜑 → Σ𝑘 ∈ ((𝐹 supp 0) ∪ (𝐺 supp 0))(((𝐹‘𝑘) − (𝐺‘𝑘))↑2) = Σ𝑘 ∈ 𝐴 (((𝐹‘𝑘) − (𝐺‘𝑘))↑2)) | ||
| Theorem | rrxmet 25442* | Euclidean space is a metric space. (Contributed by Jeff Madsen, 2-Sep-2009.) (Proof shortened by Mario Carneiro, 5-Jun-2014.) (Revised by Thierry Arnoux, 30-Jun-2019.) |
| ⊢ 𝑋 = {ℎ ∈ (ℝ ↑m 𝐼) ∣ ℎ finSupp 0} & ⊢ 𝐷 = (dist‘(ℝ^‘𝐼)) ⇒ ⊢ (𝐼 ∈ 𝑉 → 𝐷 ∈ (Met‘𝑋)) | ||
| Theorem | rrxdstprj1 25443* | The distance between two points in Euclidean space is greater than the distance between the projections onto one coordinate. (Contributed by Jeff Madsen, 2-Sep-2009.) (Revised by Mario Carneiro, 13-Sep-2015.) (Revised by Thierry Arnoux, 7-Jul-2019.) |
| ⊢ 𝑋 = {ℎ ∈ (ℝ ↑m 𝐼) ∣ ℎ finSupp 0} & ⊢ 𝐷 = (dist‘(ℝ^‘𝐼)) & ⊢ 𝑀 = ((abs ∘ − ) ↾ (ℝ × ℝ)) ⇒ ⊢ (((𝐼 ∈ 𝑉 ∧ 𝐴 ∈ 𝐼) ∧ (𝐹 ∈ 𝑋 ∧ 𝐺 ∈ 𝑋)) → ((𝐹‘𝐴)𝑀(𝐺‘𝐴)) ≤ (𝐹𝐷𝐺)) | ||
| Theorem | rrxbasefi 25444 | The base of the generalized real Euclidean space, when the dimension of the space is finite. This justifies the use of (ℝ ↑m 𝑋) for the development of the Lebesgue measure theory for n-dimensional real numbers. (Contributed by Glauco Siliprandi, 24-Dec-2020.) |
| ⊢ (𝜑 → 𝑋 ∈ Fin) & ⊢ 𝐻 = (ℝ^‘𝑋) & ⊢ 𝐵 = (Base‘𝐻) ⇒ ⊢ (𝜑 → 𝐵 = (ℝ ↑m 𝑋)) | ||
| Theorem | rrxdsfi 25445* | The distance over generalized Euclidean spaces. Finite dimensional case. (Contributed by Glauco Siliprandi, 24-Dec-2020.) |
| ⊢ 𝐻 = (ℝ^‘𝐼) & ⊢ 𝐵 = (ℝ ↑m 𝐼) ⇒ ⊢ (𝐼 ∈ Fin → (dist‘𝐻) = (𝑓 ∈ 𝐵, 𝑔 ∈ 𝐵 ↦ (√‘Σ𝑘 ∈ 𝐼 (((𝑓‘𝑘) − (𝑔‘𝑘))↑2)))) | ||
| Theorem | rrxmetfi 25446 | Euclidean space is a metric space. Finite dimensional version. (Contributed by Glauco Siliprandi, 24-Dec-2020.) |
| ⊢ 𝐷 = (dist‘(ℝ^‘𝐼)) ⇒ ⊢ (𝐼 ∈ Fin → 𝐷 ∈ (Met‘(ℝ ↑m 𝐼))) | ||
| Theorem | rrxdsfival 25447* | The value of the Euclidean distance function in a generalized real Euclidean space of finite dimension. (Contributed by AV, 15-Jan-2023.) |
| ⊢ 𝑋 = (ℝ ↑m 𝐼) & ⊢ 𝐷 = (dist‘(ℝ^‘𝐼)) ⇒ ⊢ ((𝐼 ∈ Fin ∧ 𝐹 ∈ 𝑋 ∧ 𝐺 ∈ 𝑋) → (𝐹𝐷𝐺) = (√‘Σ𝑘 ∈ 𝐼 (((𝐹‘𝑘) − (𝐺‘𝑘))↑2))) | ||
| Theorem | ehlval 25448 | Value of the Euclidean space of dimension 𝑁. (Contributed by Thierry Arnoux, 16-Jun-2019.) |
| ⊢ 𝐸 = (𝔼hil‘𝑁) ⇒ ⊢ (𝑁 ∈ ℕ0 → 𝐸 = (ℝ^‘(1...𝑁))) | ||
| Theorem | ehlbase 25449 | The base of the Euclidean space is the set of n-tuples of real numbers. (Contributed by Thierry Arnoux, 16-Jun-2019.) |
| ⊢ 𝐸 = (𝔼hil‘𝑁) ⇒ ⊢ (𝑁 ∈ ℕ0 → (ℝ ↑m (1...𝑁)) = (Base‘𝐸)) | ||
| Theorem | ehl0base 25450 | The base of the Euclidean space of dimension 0 consists only of one element, the empty set. (Contributed by AV, 12-Feb-2023.) |
| ⊢ 𝐸 = (𝔼hil‘0) ⇒ ⊢ (Base‘𝐸) = {∅} | ||
| Theorem | ehl0 25451 | The Euclidean space of dimension 0 consists of the neutral element only. (Contributed by AV, 12-Feb-2023.) |
| ⊢ 𝐸 = (𝔼hil‘0) & ⊢ 0 = (0g‘𝐸) ⇒ ⊢ (Base‘𝐸) = { 0 } | ||
| Theorem | ehleudis 25452* | The Euclidean distance function in a real Euclidean space of finite dimension. (Contributed by AV, 15-Jan-2023.) |
| ⊢ 𝐼 = (1...𝑁) & ⊢ 𝐸 = (𝔼hil‘𝑁) & ⊢ 𝑋 = (ℝ ↑m 𝐼) & ⊢ 𝐷 = (dist‘𝐸) ⇒ ⊢ (𝑁 ∈ ℕ0 → 𝐷 = (𝑓 ∈ 𝑋, 𝑔 ∈ 𝑋 ↦ (√‘Σ𝑘 ∈ 𝐼 (((𝑓‘𝑘) − (𝑔‘𝑘))↑2)))) | ||
| Theorem | ehleudisval 25453* | The value of the Euclidean distance function in a real Euclidean space of finite dimension. (Contributed by AV, 15-Jan-2023.) |
| ⊢ 𝐼 = (1...𝑁) & ⊢ 𝐸 = (𝔼hil‘𝑁) & ⊢ 𝑋 = (ℝ ↑m 𝐼) & ⊢ 𝐷 = (dist‘𝐸) ⇒ ⊢ ((𝑁 ∈ ℕ0 ∧ 𝐹 ∈ 𝑋 ∧ 𝐺 ∈ 𝑋) → (𝐹𝐷𝐺) = (√‘Σ𝑘 ∈ 𝐼 (((𝐹‘𝑘) − (𝐺‘𝑘))↑2))) | ||
| Theorem | ehl1eudis 25454* | The Euclidean distance function in a real Euclidean space of dimension 1. (Contributed by AV, 16-Jan-2023.) |
| ⊢ 𝐸 = (𝔼hil‘1) & ⊢ 𝑋 = (ℝ ↑m {1}) & ⊢ 𝐷 = (dist‘𝐸) ⇒ ⊢ 𝐷 = (𝑓 ∈ 𝑋, 𝑔 ∈ 𝑋 ↦ (abs‘((𝑓‘1) − (𝑔‘1)))) | ||
| Theorem | ehl1eudisval 25455 | The value of the Euclidean distance function in a real Euclidean space of dimension 1. (Contributed by AV, 16-Jan-2023.) |
| ⊢ 𝐸 = (𝔼hil‘1) & ⊢ 𝑋 = (ℝ ↑m {1}) & ⊢ 𝐷 = (dist‘𝐸) ⇒ ⊢ ((𝐹 ∈ 𝑋 ∧ 𝐺 ∈ 𝑋) → (𝐹𝐷𝐺) = (abs‘((𝐹‘1) − (𝐺‘1)))) | ||
| Theorem | ehl2eudis 25456* | The Euclidean distance function in a real Euclidean space of dimension 2. (Contributed by AV, 16-Jan-2023.) |
| ⊢ 𝐸 = (𝔼hil‘2) & ⊢ 𝑋 = (ℝ ↑m {1, 2}) & ⊢ 𝐷 = (dist‘𝐸) ⇒ ⊢ 𝐷 = (𝑓 ∈ 𝑋, 𝑔 ∈ 𝑋 ↦ (√‘((((𝑓‘1) − (𝑔‘1))↑2) + (((𝑓‘2) − (𝑔‘2))↑2)))) | ||
| Theorem | ehl2eudisval 25457 | The value of the Euclidean distance function in a real Euclidean space of dimension 2. (Contributed by AV, 16-Jan-2023.) |
| ⊢ 𝐸 = (𝔼hil‘2) & ⊢ 𝑋 = (ℝ ↑m {1, 2}) & ⊢ 𝐷 = (dist‘𝐸) ⇒ ⊢ ((𝐹 ∈ 𝑋 ∧ 𝐺 ∈ 𝑋) → (𝐹𝐷𝐺) = (√‘((((𝐹‘1) − (𝐺‘1))↑2) + (((𝐹‘2) − (𝐺‘2))↑2)))) | ||
| Theorem | minveclem1 25458* | Lemma for minvec 25470. The set of all distances from points of 𝑌 to 𝐴 are a nonempty set of nonnegative reals. (Contributed by Mario Carneiro, 8-May-2014.) (Revised by Mario Carneiro, 15-Oct-2015.) |
| ⊢ 𝑋 = (Base‘𝑈) & ⊢ − = (-g‘𝑈) & ⊢ 𝑁 = (norm‘𝑈) & ⊢ (𝜑 → 𝑈 ∈ ℂPreHil) & ⊢ (𝜑 → 𝑌 ∈ (LSubSp‘𝑈)) & ⊢ (𝜑 → (𝑈 ↾s 𝑌) ∈ CMetSp) & ⊢ (𝜑 → 𝐴 ∈ 𝑋) & ⊢ 𝐽 = (TopOpen‘𝑈) & ⊢ 𝑅 = ran (𝑦 ∈ 𝑌 ↦ (𝑁‘(𝐴 − 𝑦))) ⇒ ⊢ (𝜑 → (𝑅 ⊆ ℝ ∧ 𝑅 ≠ ∅ ∧ ∀𝑤 ∈ 𝑅 0 ≤ 𝑤)) | ||
| Theorem | minveclem4c 25459* | Lemma for minvec 25470. The infimum of the distances to 𝐴 is a real number. (Contributed by Mario Carneiro, 16-Jun-2014.) (Revised by Mario Carneiro, 15-Oct-2015.) (Revised by AV, 3-Oct-2020.) |
| ⊢ 𝑋 = (Base‘𝑈) & ⊢ − = (-g‘𝑈) & ⊢ 𝑁 = (norm‘𝑈) & ⊢ (𝜑 → 𝑈 ∈ ℂPreHil) & ⊢ (𝜑 → 𝑌 ∈ (LSubSp‘𝑈)) & ⊢ (𝜑 → (𝑈 ↾s 𝑌) ∈ CMetSp) & ⊢ (𝜑 → 𝐴 ∈ 𝑋) & ⊢ 𝐽 = (TopOpen‘𝑈) & ⊢ 𝑅 = ran (𝑦 ∈ 𝑌 ↦ (𝑁‘(𝐴 − 𝑦))) & ⊢ 𝑆 = inf(𝑅, ℝ, < ) ⇒ ⊢ (𝜑 → 𝑆 ∈ ℝ) | ||
| Theorem | minveclem2 25460* | Lemma for minvec 25470. Any two points 𝐾 and 𝐿 in 𝑌 are close to each other if they are close to the infimum of distance to 𝐴. (Contributed by Mario Carneiro, 9-May-2014.) (Revised by Mario Carneiro, 15-Oct-2015.) (Revised by AV, 3-Oct-2020.) |
| ⊢ 𝑋 = (Base‘𝑈) & ⊢ − = (-g‘𝑈) & ⊢ 𝑁 = (norm‘𝑈) & ⊢ (𝜑 → 𝑈 ∈ ℂPreHil) & ⊢ (𝜑 → 𝑌 ∈ (LSubSp‘𝑈)) & ⊢ (𝜑 → (𝑈 ↾s 𝑌) ∈ CMetSp) & ⊢ (𝜑 → 𝐴 ∈ 𝑋) & ⊢ 𝐽 = (TopOpen‘𝑈) & ⊢ 𝑅 = ran (𝑦 ∈ 𝑌 ↦ (𝑁‘(𝐴 − 𝑦))) & ⊢ 𝑆 = inf(𝑅, ℝ, < ) & ⊢ 𝐷 = ((dist‘𝑈) ↾ (𝑋 × 𝑋)) & ⊢ (𝜑 → 𝐵 ∈ ℝ) & ⊢ (𝜑 → 0 ≤ 𝐵) & ⊢ (𝜑 → 𝐾 ∈ 𝑌) & ⊢ (𝜑 → 𝐿 ∈ 𝑌) & ⊢ (𝜑 → ((𝐴𝐷𝐾)↑2) ≤ ((𝑆↑2) + 𝐵)) & ⊢ (𝜑 → ((𝐴𝐷𝐿)↑2) ≤ ((𝑆↑2) + 𝐵)) ⇒ ⊢ (𝜑 → ((𝐾𝐷𝐿)↑2) ≤ (4 · 𝐵)) | ||
| Theorem | minveclem3a 25461* | Lemma for minvec 25470. 𝐷 is a complete metric when restricted to 𝑌. (Contributed by Mario Carneiro, 7-May-2014.) (Revised by Mario Carneiro, 15-Oct-2015.) |
| ⊢ 𝑋 = (Base‘𝑈) & ⊢ − = (-g‘𝑈) & ⊢ 𝑁 = (norm‘𝑈) & ⊢ (𝜑 → 𝑈 ∈ ℂPreHil) & ⊢ (𝜑 → 𝑌 ∈ (LSubSp‘𝑈)) & ⊢ (𝜑 → (𝑈 ↾s 𝑌) ∈ CMetSp) & ⊢ (𝜑 → 𝐴 ∈ 𝑋) & ⊢ 𝐽 = (TopOpen‘𝑈) & ⊢ 𝑅 = ran (𝑦 ∈ 𝑌 ↦ (𝑁‘(𝐴 − 𝑦))) & ⊢ 𝑆 = inf(𝑅, ℝ, < ) & ⊢ 𝐷 = ((dist‘𝑈) ↾ (𝑋 × 𝑋)) ⇒ ⊢ (𝜑 → (𝐷 ↾ (𝑌 × 𝑌)) ∈ (CMet‘𝑌)) | ||
| Theorem | minveclem3b 25462* | Lemma for minvec 25470. The set of vectors within a fixed distance of the infimum forms a filter base. (Contributed by Mario Carneiro, 15-Oct-2015.) (Revised by AV, 3-Oct-2020.) |
| ⊢ 𝑋 = (Base‘𝑈) & ⊢ − = (-g‘𝑈) & ⊢ 𝑁 = (norm‘𝑈) & ⊢ (𝜑 → 𝑈 ∈ ℂPreHil) & ⊢ (𝜑 → 𝑌 ∈ (LSubSp‘𝑈)) & ⊢ (𝜑 → (𝑈 ↾s 𝑌) ∈ CMetSp) & ⊢ (𝜑 → 𝐴 ∈ 𝑋) & ⊢ 𝐽 = (TopOpen‘𝑈) & ⊢ 𝑅 = ran (𝑦 ∈ 𝑌 ↦ (𝑁‘(𝐴 − 𝑦))) & ⊢ 𝑆 = inf(𝑅, ℝ, < ) & ⊢ 𝐷 = ((dist‘𝑈) ↾ (𝑋 × 𝑋)) & ⊢ 𝐹 = ran (𝑟 ∈ ℝ+ ↦ {𝑦 ∈ 𝑌 ∣ ((𝐴𝐷𝑦)↑2) ≤ ((𝑆↑2) + 𝑟)}) ⇒ ⊢ (𝜑 → 𝐹 ∈ (fBas‘𝑌)) | ||
| Theorem | minveclem3 25463* | Lemma for minvec 25470. The filter formed by taking elements successively closer to the infimum is Cauchy. (Contributed by Mario Carneiro, 8-May-2014.) (Revised by Mario Carneiro, 15-Oct-2015.) |
| ⊢ 𝑋 = (Base‘𝑈) & ⊢ − = (-g‘𝑈) & ⊢ 𝑁 = (norm‘𝑈) & ⊢ (𝜑 → 𝑈 ∈ ℂPreHil) & ⊢ (𝜑 → 𝑌 ∈ (LSubSp‘𝑈)) & ⊢ (𝜑 → (𝑈 ↾s 𝑌) ∈ CMetSp) & ⊢ (𝜑 → 𝐴 ∈ 𝑋) & ⊢ 𝐽 = (TopOpen‘𝑈) & ⊢ 𝑅 = ran (𝑦 ∈ 𝑌 ↦ (𝑁‘(𝐴 − 𝑦))) & ⊢ 𝑆 = inf(𝑅, ℝ, < ) & ⊢ 𝐷 = ((dist‘𝑈) ↾ (𝑋 × 𝑋)) & ⊢ 𝐹 = ran (𝑟 ∈ ℝ+ ↦ {𝑦 ∈ 𝑌 ∣ ((𝐴𝐷𝑦)↑2) ≤ ((𝑆↑2) + 𝑟)}) ⇒ ⊢ (𝜑 → (𝑌filGen𝐹) ∈ (CauFil‘(𝐷 ↾ (𝑌 × 𝑌)))) | ||
| Theorem | minveclem4a 25464* | Lemma for minvec 25470. 𝐹 converges to a point 𝑃 in 𝑌. (Contributed by Mario Carneiro, 7-May-2014.) (Revised by Mario Carneiro, 15-Oct-2015.) |
| ⊢ 𝑋 = (Base‘𝑈) & ⊢ − = (-g‘𝑈) & ⊢ 𝑁 = (norm‘𝑈) & ⊢ (𝜑 → 𝑈 ∈ ℂPreHil) & ⊢ (𝜑 → 𝑌 ∈ (LSubSp‘𝑈)) & ⊢ (𝜑 → (𝑈 ↾s 𝑌) ∈ CMetSp) & ⊢ (𝜑 → 𝐴 ∈ 𝑋) & ⊢ 𝐽 = (TopOpen‘𝑈) & ⊢ 𝑅 = ran (𝑦 ∈ 𝑌 ↦ (𝑁‘(𝐴 − 𝑦))) & ⊢ 𝑆 = inf(𝑅, ℝ, < ) & ⊢ 𝐷 = ((dist‘𝑈) ↾ (𝑋 × 𝑋)) & ⊢ 𝐹 = ran (𝑟 ∈ ℝ+ ↦ {𝑦 ∈ 𝑌 ∣ ((𝐴𝐷𝑦)↑2) ≤ ((𝑆↑2) + 𝑟)}) & ⊢ 𝑃 = ∪ (𝐽 fLim (𝑋filGen𝐹)) ⇒ ⊢ (𝜑 → 𝑃 ∈ ((𝐽 fLim (𝑋filGen𝐹)) ∩ 𝑌)) | ||
| Theorem | minveclem4b 25465* | Lemma for minvec 25470. The convergent point of the Cauchy sequence 𝐹 is a member of the base space. (Contributed by Mario Carneiro, 16-Jun-2014.) (Revised by Mario Carneiro, 15-Oct-2015.) |
| ⊢ 𝑋 = (Base‘𝑈) & ⊢ − = (-g‘𝑈) & ⊢ 𝑁 = (norm‘𝑈) & ⊢ (𝜑 → 𝑈 ∈ ℂPreHil) & ⊢ (𝜑 → 𝑌 ∈ (LSubSp‘𝑈)) & ⊢ (𝜑 → (𝑈 ↾s 𝑌) ∈ CMetSp) & ⊢ (𝜑 → 𝐴 ∈ 𝑋) & ⊢ 𝐽 = (TopOpen‘𝑈) & ⊢ 𝑅 = ran (𝑦 ∈ 𝑌 ↦ (𝑁‘(𝐴 − 𝑦))) & ⊢ 𝑆 = inf(𝑅, ℝ, < ) & ⊢ 𝐷 = ((dist‘𝑈) ↾ (𝑋 × 𝑋)) & ⊢ 𝐹 = ran (𝑟 ∈ ℝ+ ↦ {𝑦 ∈ 𝑌 ∣ ((𝐴𝐷𝑦)↑2) ≤ ((𝑆↑2) + 𝑟)}) & ⊢ 𝑃 = ∪ (𝐽 fLim (𝑋filGen𝐹)) ⇒ ⊢ (𝜑 → 𝑃 ∈ 𝑋) | ||
| Theorem | minveclem4 25466* | Lemma for minvec 25470. The convergent point of the Cauchy sequence 𝐹 attains the minimum distance, and so is closer to 𝐴 than any other point in 𝑌. (Contributed by Mario Carneiro, 7-May-2014.) (Revised by Mario Carneiro, 15-Oct-2015.) (Revised by AV, 3-Oct-2020.) |
| ⊢ 𝑋 = (Base‘𝑈) & ⊢ − = (-g‘𝑈) & ⊢ 𝑁 = (norm‘𝑈) & ⊢ (𝜑 → 𝑈 ∈ ℂPreHil) & ⊢ (𝜑 → 𝑌 ∈ (LSubSp‘𝑈)) & ⊢ (𝜑 → (𝑈 ↾s 𝑌) ∈ CMetSp) & ⊢ (𝜑 → 𝐴 ∈ 𝑋) & ⊢ 𝐽 = (TopOpen‘𝑈) & ⊢ 𝑅 = ran (𝑦 ∈ 𝑌 ↦ (𝑁‘(𝐴 − 𝑦))) & ⊢ 𝑆 = inf(𝑅, ℝ, < ) & ⊢ 𝐷 = ((dist‘𝑈) ↾ (𝑋 × 𝑋)) & ⊢ 𝐹 = ran (𝑟 ∈ ℝ+ ↦ {𝑦 ∈ 𝑌 ∣ ((𝐴𝐷𝑦)↑2) ≤ ((𝑆↑2) + 𝑟)}) & ⊢ 𝑃 = ∪ (𝐽 fLim (𝑋filGen𝐹)) & ⊢ 𝑇 = (((((𝐴𝐷𝑃) + 𝑆) / 2)↑2) − (𝑆↑2)) ⇒ ⊢ (𝜑 → ∃𝑥 ∈ 𝑌 ∀𝑦 ∈ 𝑌 (𝑁‘(𝐴 − 𝑥)) ≤ (𝑁‘(𝐴 − 𝑦))) | ||
| Theorem | minveclem5 25467* | Lemma for minvec 25470. Discharge the assumptions in minveclem4 25466. (Contributed by Mario Carneiro, 9-May-2014.) (Revised by Mario Carneiro, 15-Oct-2015.) |
| ⊢ 𝑋 = (Base‘𝑈) & ⊢ − = (-g‘𝑈) & ⊢ 𝑁 = (norm‘𝑈) & ⊢ (𝜑 → 𝑈 ∈ ℂPreHil) & ⊢ (𝜑 → 𝑌 ∈ (LSubSp‘𝑈)) & ⊢ (𝜑 → (𝑈 ↾s 𝑌) ∈ CMetSp) & ⊢ (𝜑 → 𝐴 ∈ 𝑋) & ⊢ 𝐽 = (TopOpen‘𝑈) & ⊢ 𝑅 = ran (𝑦 ∈ 𝑌 ↦ (𝑁‘(𝐴 − 𝑦))) & ⊢ 𝑆 = inf(𝑅, ℝ, < ) & ⊢ 𝐷 = ((dist‘𝑈) ↾ (𝑋 × 𝑋)) ⇒ ⊢ (𝜑 → ∃𝑥 ∈ 𝑌 ∀𝑦 ∈ 𝑌 (𝑁‘(𝐴 − 𝑥)) ≤ (𝑁‘(𝐴 − 𝑦))) | ||
| Theorem | minveclem6 25468* | Lemma for minvec 25470. Any minimal point is less than 𝑆 away from 𝐴. (Contributed by Mario Carneiro, 9-May-2014.) (Revised by Mario Carneiro, 15-Oct-2015.) (Revised by AV, 3-Oct-2020.) |
| ⊢ 𝑋 = (Base‘𝑈) & ⊢ − = (-g‘𝑈) & ⊢ 𝑁 = (norm‘𝑈) & ⊢ (𝜑 → 𝑈 ∈ ℂPreHil) & ⊢ (𝜑 → 𝑌 ∈ (LSubSp‘𝑈)) & ⊢ (𝜑 → (𝑈 ↾s 𝑌) ∈ CMetSp) & ⊢ (𝜑 → 𝐴 ∈ 𝑋) & ⊢ 𝐽 = (TopOpen‘𝑈) & ⊢ 𝑅 = ran (𝑦 ∈ 𝑌 ↦ (𝑁‘(𝐴 − 𝑦))) & ⊢ 𝑆 = inf(𝑅, ℝ, < ) & ⊢ 𝐷 = ((dist‘𝑈) ↾ (𝑋 × 𝑋)) ⇒ ⊢ ((𝜑 ∧ 𝑥 ∈ 𝑌) → (((𝐴𝐷𝑥)↑2) ≤ ((𝑆↑2) + 0) ↔ ∀𝑦 ∈ 𝑌 (𝑁‘(𝐴 − 𝑥)) ≤ (𝑁‘(𝐴 − 𝑦)))) | ||
| Theorem | minveclem7 25469* | Lemma for minvec 25470. Since any two minimal points are distance zero away from each other, the minimal point is unique. (Contributed by Mario Carneiro, 9-May-2014.) (Revised by Mario Carneiro, 15-Oct-2015.) |
| ⊢ 𝑋 = (Base‘𝑈) & ⊢ − = (-g‘𝑈) & ⊢ 𝑁 = (norm‘𝑈) & ⊢ (𝜑 → 𝑈 ∈ ℂPreHil) & ⊢ (𝜑 → 𝑌 ∈ (LSubSp‘𝑈)) & ⊢ (𝜑 → (𝑈 ↾s 𝑌) ∈ CMetSp) & ⊢ (𝜑 → 𝐴 ∈ 𝑋) & ⊢ 𝐽 = (TopOpen‘𝑈) & ⊢ 𝑅 = ran (𝑦 ∈ 𝑌 ↦ (𝑁‘(𝐴 − 𝑦))) & ⊢ 𝑆 = inf(𝑅, ℝ, < ) & ⊢ 𝐷 = ((dist‘𝑈) ↾ (𝑋 × 𝑋)) ⇒ ⊢ (𝜑 → ∃!𝑥 ∈ 𝑌 ∀𝑦 ∈ 𝑌 (𝑁‘(𝐴 − 𝑥)) ≤ (𝑁‘(𝐴 − 𝑦))) | ||
| Theorem | minvec 25470* | Minimizing vector theorem, or the Hilbert projection theorem. There is exactly one vector in a complete subspace 𝑊 that minimizes the distance to an arbitrary vector 𝐴 in a parent inner product space. Theorem 3.3-1 of [Kreyszig] p. 144, specialized to subspaces instead of convex subsets. (Contributed by NM, 11-Apr-2008.) (Proof shortened by Mario Carneiro, 9-May-2014.) (Revised by Mario Carneiro, 15-Oct-2015.) (Proof shortened by AV, 3-Oct-2020.) |
| ⊢ 𝑋 = (Base‘𝑈) & ⊢ − = (-g‘𝑈) & ⊢ 𝑁 = (norm‘𝑈) & ⊢ (𝜑 → 𝑈 ∈ ℂPreHil) & ⊢ (𝜑 → 𝑌 ∈ (LSubSp‘𝑈)) & ⊢ (𝜑 → (𝑈 ↾s 𝑌) ∈ CMetSp) & ⊢ (𝜑 → 𝐴 ∈ 𝑋) ⇒ ⊢ (𝜑 → ∃!𝑥 ∈ 𝑌 ∀𝑦 ∈ 𝑌 (𝑁‘(𝐴 − 𝑥)) ≤ (𝑁‘(𝐴 − 𝑦))) | ||
| Theorem | pjthlem1 25471* | Lemma for pjth 25473. (Contributed by NM, 10-Oct-1999.) (Revised by Mario Carneiro, 17-Oct-2015.) (Proof shortened by AV, 10-Jul-2022.) |
| ⊢ 𝑉 = (Base‘𝑊) & ⊢ 𝑁 = (norm‘𝑊) & ⊢ + = (+g‘𝑊) & ⊢ − = (-g‘𝑊) & ⊢ , = (·𝑖‘𝑊) & ⊢ 𝐿 = (LSubSp‘𝑊) & ⊢ (𝜑 → 𝑊 ∈ ℂHil) & ⊢ (𝜑 → 𝑈 ∈ 𝐿) & ⊢ (𝜑 → 𝐴 ∈ 𝑉) & ⊢ (𝜑 → 𝐵 ∈ 𝑈) & ⊢ (𝜑 → ∀𝑥 ∈ 𝑈 (𝑁‘𝐴) ≤ (𝑁‘(𝐴 − 𝑥))) & ⊢ 𝑇 = ((𝐴 , 𝐵) / ((𝐵 , 𝐵) + 1)) ⇒ ⊢ (𝜑 → (𝐴 , 𝐵) = 0) | ||
| Theorem | pjthlem2 25472 | Lemma for pjth 25473. (Contributed by NM, 10-Oct-1999.) (Revised by Mario Carneiro, 15-May-2014.) |
| ⊢ 𝑉 = (Base‘𝑊) & ⊢ 𝑁 = (norm‘𝑊) & ⊢ + = (+g‘𝑊) & ⊢ − = (-g‘𝑊) & ⊢ , = (·𝑖‘𝑊) & ⊢ 𝐿 = (LSubSp‘𝑊) & ⊢ (𝜑 → 𝑊 ∈ ℂHil) & ⊢ (𝜑 → 𝑈 ∈ 𝐿) & ⊢ (𝜑 → 𝐴 ∈ 𝑉) & ⊢ 𝐽 = (TopOpen‘𝑊) & ⊢ ⊕ = (LSSum‘𝑊) & ⊢ 𝑂 = (ocv‘𝑊) & ⊢ (𝜑 → 𝑈 ∈ (Clsd‘𝐽)) ⇒ ⊢ (𝜑 → 𝐴 ∈ (𝑈 ⊕ (𝑂‘𝑈))) | ||
| Theorem | pjth 25473 | Projection Theorem: Any Hilbert space vector 𝐴 can be decomposed uniquely into a member 𝑥 of a closed subspace 𝐻 and a member 𝑦 of the complement of the subspace. Theorem 3.7(i) of [Beran] p. 102 (existence part). (Contributed by NM, 23-Oct-1999.) (Revised by Mario Carneiro, 14-May-2014.) |
| ⊢ 𝑉 = (Base‘𝑊) & ⊢ ⊕ = (LSSum‘𝑊) & ⊢ 𝑂 = (ocv‘𝑊) & ⊢ 𝐽 = (TopOpen‘𝑊) & ⊢ 𝐿 = (LSubSp‘𝑊) ⇒ ⊢ ((𝑊 ∈ ℂHil ∧ 𝑈 ∈ 𝐿 ∧ 𝑈 ∈ (Clsd‘𝐽)) → (𝑈 ⊕ (𝑂‘𝑈)) = 𝑉) | ||
| Theorem | pjth2 25474 | Projection Theorem with abbreviations: A topologically closed subspace is a projection subspace. (Contributed by Mario Carneiro, 17-Oct-2015.) |
| ⊢ 𝐽 = (TopOpen‘𝑊) & ⊢ 𝐿 = (LSubSp‘𝑊) & ⊢ 𝐾 = (proj‘𝑊) ⇒ ⊢ ((𝑊 ∈ ℂHil ∧ 𝑈 ∈ 𝐿 ∧ 𝑈 ∈ (Clsd‘𝐽)) → 𝑈 ∈ dom 𝐾) | ||
| Theorem | cldcss 25475 | Corollary of the Projection Theorem: A topologically closed subspace is algebraically closed in Hilbert space. (Contributed by Mario Carneiro, 17-Oct-2015.) |
| ⊢ 𝑉 = (Base‘𝑊) & ⊢ 𝐽 = (TopOpen‘𝑊) & ⊢ 𝐿 = (LSubSp‘𝑊) & ⊢ 𝐶 = (ClSubSp‘𝑊) ⇒ ⊢ (𝑊 ∈ ℂHil → (𝑈 ∈ 𝐶 ↔ (𝑈 ∈ 𝐿 ∧ 𝑈 ∈ (Clsd‘𝐽)))) | ||
| Theorem | cldcss2 25476 | Corollary of the Projection Theorem: A topologically closed subspace is algebraically closed in Hilbert space. (Contributed by Mario Carneiro, 17-Oct-2015.) |
| ⊢ 𝑉 = (Base‘𝑊) & ⊢ 𝐽 = (TopOpen‘𝑊) & ⊢ 𝐿 = (LSubSp‘𝑊) & ⊢ 𝐶 = (ClSubSp‘𝑊) ⇒ ⊢ (𝑊 ∈ ℂHil → 𝐶 = (𝐿 ∩ (Clsd‘𝐽))) | ||
| Theorem | hlhil 25477 | Corollary of the Projection Theorem: A subcomplex Hilbert space is a Hilbert space (in the algebraic sense, meaning that all algebraically closed subspaces have a projection decomposition). (Contributed by Mario Carneiro, 17-Oct-2015.) |
| ⊢ (𝑊 ∈ ℂHil → 𝑊 ∈ Hil) | ||
| Theorem | addcncf 25478* | The addition of two continuous complex functions is continuous. (Contributed by Glauco Siliprandi, 11-Dec-2019.) |
| ⊢ (𝜑 → (𝑥 ∈ 𝑋 ↦ 𝐴) ∈ (𝑋–cn→ℂ)) & ⊢ (𝜑 → (𝑥 ∈ 𝑋 ↦ 𝐵) ∈ (𝑋–cn→ℂ)) ⇒ ⊢ (𝜑 → (𝑥 ∈ 𝑋 ↦ (𝐴 + 𝐵)) ∈ (𝑋–cn→ℂ)) | ||
| Theorem | subcncf 25479* | The subtraction of two continuous complex functions is continuous. (Contributed by Glauco Siliprandi, 11-Dec-2019.) |
| ⊢ (𝜑 → (𝑥 ∈ 𝑋 ↦ 𝐴) ∈ (𝑋–cn→ℂ)) & ⊢ (𝜑 → (𝑥 ∈ 𝑋 ↦ 𝐵) ∈ (𝑋–cn→ℂ)) ⇒ ⊢ (𝜑 → (𝑥 ∈ 𝑋 ↦ (𝐴 − 𝐵)) ∈ (𝑋–cn→ℂ)) | ||
| Theorem | mulcncf 25480* | The multiplication of two continuous complex functions is continuous. (Contributed by Glauco Siliprandi, 29-Jun-2017.) Avoid ax-mulf 11235. (Revised by GG, 16-Mar-2025.) |
| ⊢ (𝜑 → (𝑥 ∈ 𝑋 ↦ 𝐴) ∈ (𝑋–cn→ℂ)) & ⊢ (𝜑 → (𝑥 ∈ 𝑋 ↦ 𝐵) ∈ (𝑋–cn→ℂ)) ⇒ ⊢ (𝜑 → (𝑥 ∈ 𝑋 ↦ (𝐴 · 𝐵)) ∈ (𝑋–cn→ℂ)) | ||
| Theorem | mulcncfOLD 25481* | Obsolete version of mulcncf 25480 as of 9-Apr-2025. (Contributed by Glauco Siliprandi, 29-Jun-2017.) (Proof modification is discouraged.) (New usage is discouraged.) |
| ⊢ (𝜑 → (𝑥 ∈ 𝑋 ↦ 𝐴) ∈ (𝑋–cn→ℂ)) & ⊢ (𝜑 → (𝑥 ∈ 𝑋 ↦ 𝐵) ∈ (𝑋–cn→ℂ)) ⇒ ⊢ (𝜑 → (𝑥 ∈ 𝑋 ↦ (𝐴 · 𝐵)) ∈ (𝑋–cn→ℂ)) | ||
| Theorem | divcncf 25482* | The quotient of two continuous complex functions is continuous. (Contributed by Glauco Siliprandi, 11-Dec-2019.) |
| ⊢ (𝜑 → (𝑥 ∈ 𝑋 ↦ 𝐴) ∈ (𝑋–cn→ℂ)) & ⊢ (𝜑 → (𝑥 ∈ 𝑋 ↦ 𝐵) ∈ (𝑋–cn→(ℂ ∖ {0}))) ⇒ ⊢ (𝜑 → (𝑥 ∈ 𝑋 ↦ (𝐴 / 𝐵)) ∈ (𝑋–cn→ℂ)) | ||
| Theorem | pmltpclem1 25483* | Lemma for pmltpc 25485. (Contributed by Mario Carneiro, 1-Jul-2014.) |
| ⊢ (𝜑 → 𝐴 ∈ 𝑆) & ⊢ (𝜑 → 𝐵 ∈ 𝑆) & ⊢ (𝜑 → 𝐶 ∈ 𝑆) & ⊢ (𝜑 → 𝐴 < 𝐵) & ⊢ (𝜑 → 𝐵 < 𝐶) & ⊢ (𝜑 → (((𝐹‘𝐴) < (𝐹‘𝐵) ∧ (𝐹‘𝐶) < (𝐹‘𝐵)) ∨ ((𝐹‘𝐵) < (𝐹‘𝐴) ∧ (𝐹‘𝐵) < (𝐹‘𝐶)))) ⇒ ⊢ (𝜑 → ∃𝑎 ∈ 𝑆 ∃𝑏 ∈ 𝑆 ∃𝑐 ∈ 𝑆 (𝑎 < 𝑏 ∧ 𝑏 < 𝑐 ∧ (((𝐹‘𝑎) < (𝐹‘𝑏) ∧ (𝐹‘𝑐) < (𝐹‘𝑏)) ∨ ((𝐹‘𝑏) < (𝐹‘𝑎) ∧ (𝐹‘𝑏) < (𝐹‘𝑐))))) | ||
| Theorem | pmltpclem2 25484* | Lemma for pmltpc 25485. (Contributed by Mario Carneiro, 1-Jul-2014.) |
| ⊢ (𝜑 → 𝐹 ∈ (ℝ ↑pm ℝ)) & ⊢ (𝜑 → 𝐴 ⊆ dom 𝐹) & ⊢ (𝜑 → 𝑈 ∈ 𝐴) & ⊢ (𝜑 → 𝑉 ∈ 𝐴) & ⊢ (𝜑 → 𝑊 ∈ 𝐴) & ⊢ (𝜑 → 𝑋 ∈ 𝐴) & ⊢ (𝜑 → 𝑈 ≤ 𝑉) & ⊢ (𝜑 → 𝑊 ≤ 𝑋) & ⊢ (𝜑 → ¬ (𝐹‘𝑈) ≤ (𝐹‘𝑉)) & ⊢ (𝜑 → ¬ (𝐹‘𝑋) ≤ (𝐹‘𝑊)) ⇒ ⊢ (𝜑 → ∃𝑎 ∈ 𝐴 ∃𝑏 ∈ 𝐴 ∃𝑐 ∈ 𝐴 (𝑎 < 𝑏 ∧ 𝑏 < 𝑐 ∧ (((𝐹‘𝑎) < (𝐹‘𝑏) ∧ (𝐹‘𝑐) < (𝐹‘𝑏)) ∨ ((𝐹‘𝑏) < (𝐹‘𝑎) ∧ (𝐹‘𝑏) < (𝐹‘𝑐))))) | ||
| Theorem | pmltpc 25485* | Any function on the reals is either increasing, decreasing, or has a triple of points in a vee formation. (This theorem was created on demand by Mario Carneiro for the 6PCM conference in Bialystok, 1-Jul-2014.) (Contributed by Mario Carneiro, 1-Jul-2014.) |
| ⊢ ((𝐹 ∈ (ℝ ↑pm ℝ) ∧ 𝐴 ⊆ dom 𝐹) → (∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝑥 ≤ 𝑦 → (𝐹‘𝑥) ≤ (𝐹‘𝑦)) ∨ ∀𝑥 ∈ 𝐴 ∀𝑦 ∈ 𝐴 (𝑥 ≤ 𝑦 → (𝐹‘𝑦) ≤ (𝐹‘𝑥)) ∨ ∃𝑎 ∈ 𝐴 ∃𝑏 ∈ 𝐴 ∃𝑐 ∈ 𝐴 (𝑎 < 𝑏 ∧ 𝑏 < 𝑐 ∧ (((𝐹‘𝑎) < (𝐹‘𝑏) ∧ (𝐹‘𝑐) < (𝐹‘𝑏)) ∨ ((𝐹‘𝑏) < (𝐹‘𝑎) ∧ (𝐹‘𝑏) < (𝐹‘𝑐)))))) | ||
| Theorem | ivthlem1 25486* | Lemma for ivth 25489. The set 𝑆 of all 𝑥 values with (𝐹‘𝑥) less than 𝑈 is lower bounded by 𝐴 and upper bounded by 𝐵. (Contributed by Mario Carneiro, 17-Jun-2014.) |
| ⊢ (𝜑 → 𝐴 ∈ ℝ) & ⊢ (𝜑 → 𝐵 ∈ ℝ) & ⊢ (𝜑 → 𝑈 ∈ ℝ) & ⊢ (𝜑 → 𝐴 < 𝐵) & ⊢ (𝜑 → (𝐴[,]𝐵) ⊆ 𝐷) & ⊢ (𝜑 → 𝐹 ∈ (𝐷–cn→ℂ)) & ⊢ ((𝜑 ∧ 𝑥 ∈ (𝐴[,]𝐵)) → (𝐹‘𝑥) ∈ ℝ) & ⊢ (𝜑 → ((𝐹‘𝐴) < 𝑈 ∧ 𝑈 < (𝐹‘𝐵))) & ⊢ 𝑆 = {𝑥 ∈ (𝐴[,]𝐵) ∣ (𝐹‘𝑥) ≤ 𝑈} ⇒ ⊢ (𝜑 → (𝐴 ∈ 𝑆 ∧ ∀𝑧 ∈ 𝑆 𝑧 ≤ 𝐵)) | ||
| Theorem | ivthlem2 25487* | Lemma for ivth 25489. Show that the supremum of 𝑆 cannot be less than 𝑈. If it was, continuity of 𝐹 implies that there are points just above the supremum that are also less than 𝑈, a contradiction. (Contributed by Mario Carneiro, 17-Jun-2014.) |
| ⊢ (𝜑 → 𝐴 ∈ ℝ) & ⊢ (𝜑 → 𝐵 ∈ ℝ) & ⊢ (𝜑 → 𝑈 ∈ ℝ) & ⊢ (𝜑 → 𝐴 < 𝐵) & ⊢ (𝜑 → (𝐴[,]𝐵) ⊆ 𝐷) & ⊢ (𝜑 → 𝐹 ∈ (𝐷–cn→ℂ)) & ⊢ ((𝜑 ∧ 𝑥 ∈ (𝐴[,]𝐵)) → (𝐹‘𝑥) ∈ ℝ) & ⊢ (𝜑 → ((𝐹‘𝐴) < 𝑈 ∧ 𝑈 < (𝐹‘𝐵))) & ⊢ 𝑆 = {𝑥 ∈ (𝐴[,]𝐵) ∣ (𝐹‘𝑥) ≤ 𝑈} & ⊢ 𝐶 = sup(𝑆, ℝ, < ) ⇒ ⊢ (𝜑 → ¬ (𝐹‘𝐶) < 𝑈) | ||
| Theorem | ivthlem3 25488* | Lemma for ivth 25489, the intermediate value theorem. Show that (𝐹‘𝐶) cannot be greater than 𝑈, and so establish the existence of a root of the function. (Contributed by Mario Carneiro, 30-Apr-2014.) (Revised by Mario Carneiro, 17-Jun-2014.) |
| ⊢ (𝜑 → 𝐴 ∈ ℝ) & ⊢ (𝜑 → 𝐵 ∈ ℝ) & ⊢ (𝜑 → 𝑈 ∈ ℝ) & ⊢ (𝜑 → 𝐴 < 𝐵) & ⊢ (𝜑 → (𝐴[,]𝐵) ⊆ 𝐷) & ⊢ (𝜑 → 𝐹 ∈ (𝐷–cn→ℂ)) & ⊢ ((𝜑 ∧ 𝑥 ∈ (𝐴[,]𝐵)) → (𝐹‘𝑥) ∈ ℝ) & ⊢ (𝜑 → ((𝐹‘𝐴) < 𝑈 ∧ 𝑈 < (𝐹‘𝐵))) & ⊢ 𝑆 = {𝑥 ∈ (𝐴[,]𝐵) ∣ (𝐹‘𝑥) ≤ 𝑈} & ⊢ 𝐶 = sup(𝑆, ℝ, < ) ⇒ ⊢ (𝜑 → (𝐶 ∈ (𝐴(,)𝐵) ∧ (𝐹‘𝐶) = 𝑈)) | ||
| Theorem | ivth 25489* | The intermediate value theorem, increasing case. This is Metamath 100 proof #79. (Contributed by Paul Chapman, 22-Jan-2008.) (Proof shortened by Mario Carneiro, 30-Apr-2014.) |
| ⊢ (𝜑 → 𝐴 ∈ ℝ) & ⊢ (𝜑 → 𝐵 ∈ ℝ) & ⊢ (𝜑 → 𝑈 ∈ ℝ) & ⊢ (𝜑 → 𝐴 < 𝐵) & ⊢ (𝜑 → (𝐴[,]𝐵) ⊆ 𝐷) & ⊢ (𝜑 → 𝐹 ∈ (𝐷–cn→ℂ)) & ⊢ ((𝜑 ∧ 𝑥 ∈ (𝐴[,]𝐵)) → (𝐹‘𝑥) ∈ ℝ) & ⊢ (𝜑 → ((𝐹‘𝐴) < 𝑈 ∧ 𝑈 < (𝐹‘𝐵))) ⇒ ⊢ (𝜑 → ∃𝑐 ∈ (𝐴(,)𝐵)(𝐹‘𝑐) = 𝑈) | ||
| Theorem | ivth2 25490* | The intermediate value theorem, decreasing case. (Contributed by Paul Chapman, 22-Jan-2008.) (Revised by Mario Carneiro, 30-Apr-2014.) |
| ⊢ (𝜑 → 𝐴 ∈ ℝ) & ⊢ (𝜑 → 𝐵 ∈ ℝ) & ⊢ (𝜑 → 𝑈 ∈ ℝ) & ⊢ (𝜑 → 𝐴 < 𝐵) & ⊢ (𝜑 → (𝐴[,]𝐵) ⊆ 𝐷) & ⊢ (𝜑 → 𝐹 ∈ (𝐷–cn→ℂ)) & ⊢ ((𝜑 ∧ 𝑥 ∈ (𝐴[,]𝐵)) → (𝐹‘𝑥) ∈ ℝ) & ⊢ (𝜑 → ((𝐹‘𝐵) < 𝑈 ∧ 𝑈 < (𝐹‘𝐴))) ⇒ ⊢ (𝜑 → ∃𝑐 ∈ (𝐴(,)𝐵)(𝐹‘𝑐) = 𝑈) | ||
| Theorem | ivthle 25491* | The intermediate value theorem with weak inequality, increasing case. (Contributed by Mario Carneiro, 12-Aug-2014.) |
| ⊢ (𝜑 → 𝐴 ∈ ℝ) & ⊢ (𝜑 → 𝐵 ∈ ℝ) & ⊢ (𝜑 → 𝑈 ∈ ℝ) & ⊢ (𝜑 → 𝐴 < 𝐵) & ⊢ (𝜑 → (𝐴[,]𝐵) ⊆ 𝐷) & ⊢ (𝜑 → 𝐹 ∈ (𝐷–cn→ℂ)) & ⊢ ((𝜑 ∧ 𝑥 ∈ (𝐴[,]𝐵)) → (𝐹‘𝑥) ∈ ℝ) & ⊢ (𝜑 → ((𝐹‘𝐴) ≤ 𝑈 ∧ 𝑈 ≤ (𝐹‘𝐵))) ⇒ ⊢ (𝜑 → ∃𝑐 ∈ (𝐴[,]𝐵)(𝐹‘𝑐) = 𝑈) | ||
| Theorem | ivthle2 25492* | The intermediate value theorem with weak inequality, decreasing case. (Contributed by Mario Carneiro, 12-May-2014.) |
| ⊢ (𝜑 → 𝐴 ∈ ℝ) & ⊢ (𝜑 → 𝐵 ∈ ℝ) & ⊢ (𝜑 → 𝑈 ∈ ℝ) & ⊢ (𝜑 → 𝐴 < 𝐵) & ⊢ (𝜑 → (𝐴[,]𝐵) ⊆ 𝐷) & ⊢ (𝜑 → 𝐹 ∈ (𝐷–cn→ℂ)) & ⊢ ((𝜑 ∧ 𝑥 ∈ (𝐴[,]𝐵)) → (𝐹‘𝑥) ∈ ℝ) & ⊢ (𝜑 → ((𝐹‘𝐵) ≤ 𝑈 ∧ 𝑈 ≤ (𝐹‘𝐴))) ⇒ ⊢ (𝜑 → ∃𝑐 ∈ (𝐴[,]𝐵)(𝐹‘𝑐) = 𝑈) | ||
| Theorem | ivthicc 25493* | The interval between any two points of a continuous real function is contained in the range of the function. Equivalently, the range of a continuous real function is convex. (Contributed by Mario Carneiro, 12-Aug-2014.) |
| ⊢ (𝜑 → 𝐴 ∈ ℝ) & ⊢ (𝜑 → 𝐵 ∈ ℝ) & ⊢ (𝜑 → 𝑀 ∈ (𝐴[,]𝐵)) & ⊢ (𝜑 → 𝑁 ∈ (𝐴[,]𝐵)) & ⊢ (𝜑 → (𝐴[,]𝐵) ⊆ 𝐷) & ⊢ (𝜑 → 𝐹 ∈ (𝐷–cn→ℂ)) & ⊢ ((𝜑 ∧ 𝑥 ∈ (𝐴[,]𝐵)) → (𝐹‘𝑥) ∈ ℝ) ⇒ ⊢ (𝜑 → ((𝐹‘𝑀)[,](𝐹‘𝑁)) ⊆ ran 𝐹) | ||
| Theorem | evthicc 25494* | Specialization of the Extreme Value Theorem to a closed interval of ℝ. (Contributed by Mario Carneiro, 12-Aug-2014.) |
| ⊢ (𝜑 → 𝐴 ∈ ℝ) & ⊢ (𝜑 → 𝐵 ∈ ℝ) & ⊢ (𝜑 → 𝐴 ≤ 𝐵) & ⊢ (𝜑 → 𝐹 ∈ ((𝐴[,]𝐵)–cn→ℝ)) ⇒ ⊢ (𝜑 → (∃𝑥 ∈ (𝐴[,]𝐵)∀𝑦 ∈ (𝐴[,]𝐵)(𝐹‘𝑦) ≤ (𝐹‘𝑥) ∧ ∃𝑧 ∈ (𝐴[,]𝐵)∀𝑤 ∈ (𝐴[,]𝐵)(𝐹‘𝑧) ≤ (𝐹‘𝑤))) | ||
| Theorem | evthicc2 25495* | Combine ivthicc 25493 with evthicc 25494 to exactly describe the image of a closed interval. (Contributed by Mario Carneiro, 19-Feb-2015.) |
| ⊢ (𝜑 → 𝐴 ∈ ℝ) & ⊢ (𝜑 → 𝐵 ∈ ℝ) & ⊢ (𝜑 → 𝐴 ≤ 𝐵) & ⊢ (𝜑 → 𝐹 ∈ ((𝐴[,]𝐵)–cn→ℝ)) ⇒ ⊢ (𝜑 → ∃𝑥 ∈ ℝ ∃𝑦 ∈ ℝ ran 𝐹 = (𝑥[,]𝑦)) | ||
| Theorem | cniccbdd 25496* | A continuous function on a closed interval is bounded. (Contributed by Mario Carneiro, 7-Sep-2014.) |
| ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ 𝐹 ∈ ((𝐴[,]𝐵)–cn→ℂ)) → ∃𝑥 ∈ ℝ ∀𝑦 ∈ (𝐴[,]𝐵)(abs‘(𝐹‘𝑦)) ≤ 𝑥) | ||
| Syntax | covol 25497 | Extend class notation with the outer Lebesgue measure. |
| class vol* | ||
| Syntax | cvol 25498 | Extend class notation with the Lebesgue measure. |
| class vol | ||
| Definition | df-ovol 25499* | Define the outer Lebesgue measure for subsets of the reals. Here 𝑓 is a function from the positive integers to pairs 〈𝑎, 𝑏〉 with 𝑎 ≤ 𝑏, and the outer volume of the set 𝑥 is the infimum over all such functions such that the union of the open intervals (𝑎, 𝑏) covers 𝑥 of the sum of 𝑏 − 𝑎. (Contributed by Mario Carneiro, 16-Mar-2014.) (Revised by AV, 17-Sep-2020.) |
| ⊢ vol* = (𝑥 ∈ 𝒫 ℝ ↦ inf({𝑦 ∈ ℝ* ∣ ∃𝑓 ∈ (( ≤ ∩ (ℝ × ℝ)) ↑m ℕ)(𝑥 ⊆ ∪ ran ((,) ∘ 𝑓) ∧ 𝑦 = sup(ran seq1( + , ((abs ∘ − ) ∘ 𝑓)), ℝ*, < ))}, ℝ*, < )) | ||
| Definition | df-vol 25500* | Define the Lebesgue measure, which is just the outer measure with a peculiar domain of definition. The property of being Lebesgue-measurable can be expressed as 𝐴 ∈ dom vol. (Contributed by Mario Carneiro, 17-Mar-2014.) |
| ⊢ vol = (vol* ↾ {𝑥 ∣ ∀𝑦 ∈ (◡vol* “ ℝ)(vol*‘𝑦) = ((vol*‘(𝑦 ∩ 𝑥)) + (vol*‘(𝑦 ∖ 𝑥)))}) | ||
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