HomeTheorem List (p. 341 of 507)
GIF version.
Mirrors > Metamath Home Page > MPE Home Page > Theorem List Contents > Recent Proofs This page: Page List
| Home |
Metamath
Proof Explorer Theorem List (p. 341 of 507) | < Previous Next > |
| Bad symbols? Try the
GIF version. |
||
|
Mirrors > Metamath Home Page > MPE Home Page > Theorem List Contents > Recent Proofs This page: Page List |
||
| Color key: | Metamath Proof Explorer
(1-31307) |
Hilbert Space Explorer
(31308-32830) |
Users' Mathboxes
(32831-50694) |
| Type | Label | Description |
|---|---|---|
| Statement | ||
| Theorem | vieta 34001* | Vieta's Formulas: Coefficients of a monic polynomial 𝐹 expressed as a product of linear polynomials of the form 𝑋 − 𝑍 can be expressed in terms of elementary symmetric polynomials. The formulas appear in Chapter 6 of [Lang], p. 190. Theorem vieta1 26510 is a special case for the complex numbers, for the case 𝐾 = 1. (Contributed by Thierry Arnoux, 15-Feb-2026.) |
| ⊢ 𝑊 = (Poly1‘𝑅) & ⊢ 𝐵 = (Base‘𝑅) & ⊢ − = (-g‘𝑊) & ⊢ 𝑀 = (mulGrp‘𝑊) & ⊢ 𝑄 = (𝐼 eval 𝑅) & ⊢ 𝐸 = (𝐼eSymPoly𝑅) & ⊢ 𝑁 = (invg‘𝑅) & ⊢ 1 = (1r‘𝑅) & ⊢ · = (.r‘𝑅) & ⊢ 𝑋 = (var1‘𝑅) & ⊢ 𝐴 = (algSc‘𝑊) & ⊢ ↑ = (.g‘(mulGrp‘𝑅)) & ⊢ 𝐻 = (♯‘𝐼) & ⊢ (𝜑 → 𝐼 ∈ Fin) & ⊢ (𝜑 → 𝑅 ∈ IDomn) & ⊢ (𝜑 → 𝑍:𝐼⟶𝐵) & ⊢ 𝐹 = (𝑀 Σg (𝑛 ∈ 𝐼 ↦ (𝑋 − (𝐴‘(𝑍‘𝑛))))) & ⊢ (𝜑 → 𝐾 ∈ (0...𝐻)) & ⊢ 𝐶 = (coe1‘𝐹) ⇒ ⊢ (𝜑 → (𝐶‘(𝐻 − 𝐾)) = ((𝐾 ↑ (𝑁‘ 1 )) · ((𝑄‘(𝐸‘𝐾))‘𝑍))) | ||
| Theorem | sra1r 34002 | The unity element of a subring algebra. (Contributed by Thierry Arnoux, 24-Jul-2023.) |
| ⊢ (𝜑 → 𝐴 = ((subringAlg ‘𝑊)‘𝑆)) & ⊢ (𝜑 → 1 = (1r‘𝑊)) & ⊢ (𝜑 → 𝑆 ⊆ (Base‘𝑊)) ⇒ ⊢ (𝜑 → 1 = (1r‘𝐴)) | ||
| Theorem | sradrng 34003 | Condition for a subring algebra to be a division ring. (Contributed by Thierry Arnoux, 29-Jul-2023.) |
| ⊢ 𝐴 = ((subringAlg ‘𝑅)‘𝑉) & ⊢ 𝐵 = (Base‘𝑅) ⇒ ⊢ ((𝑅 ∈ DivRing ∧ 𝑉 ⊆ 𝐵) → 𝐴 ∈ DivRing) | ||
| Theorem | sraidom 34004 | Condition for a subring algebra to be an integral domain. (Contributed by Thierry Arnoux, 13-Oct-2025.) |
| ⊢ 𝐴 = ((subringAlg ‘𝑅)‘𝑉) & ⊢ 𝐵 = (Base‘𝑅) & ⊢ (𝜑 → 𝑅 ∈ IDomn) & ⊢ (𝜑 → 𝑉 ⊆ 𝐵) ⇒ ⊢ (𝜑 → 𝐴 ∈ IDomn) | ||
| Theorem | srasubrg 34005 | A subring of the original structure is also a subring of the constructed subring algebra. (Contributed by Thierry Arnoux, 24-Jul-2023.) |
| ⊢ (𝜑 → 𝐴 = ((subringAlg ‘𝑊)‘𝑆)) & ⊢ (𝜑 → 𝑈 ∈ (SubRing‘𝑊)) & ⊢ (𝜑 → 𝑆 ⊆ (Base‘𝑊)) ⇒ ⊢ (𝜑 → 𝑈 ∈ (SubRing‘𝐴)) | ||
| Theorem | sralvec 34006 | Given a sub division ring 𝐹 of a division ring 𝐸, 𝐸 may be considered as a vector space over 𝐹, which becomes the field of scalars. (Contributed by Thierry Arnoux, 24-May-2023.) |
| ⊢ 𝐴 = ((subringAlg ‘𝐸)‘𝑈) & ⊢ 𝐹 = (𝐸 ↾s 𝑈) ⇒ ⊢ ((𝐸 ∈ DivRing ∧ 𝐹 ∈ DivRing ∧ 𝑈 ∈ (SubRing‘𝐸)) → 𝐴 ∈ LVec) | ||
| Theorem | srafldlvec 34007 | Given a subfield 𝐹 of a field 𝐸, 𝐸 may be considered as a vector space over 𝐹, which becomes the field of scalars. (Contributed by Thierry Arnoux, 24-May-2023.) |
| ⊢ 𝐴 = ((subringAlg ‘𝐸)‘𝑈) & ⊢ 𝐹 = (𝐸 ↾s 𝑈) ⇒ ⊢ ((𝐸 ∈ Field ∧ 𝐹 ∈ Field ∧ 𝑈 ∈ (SubRing‘𝐸)) → 𝐴 ∈ LVec) | ||
| Theorem | resssra 34008 | The subring algebra of a restricted structure is the restriction of the subring algebra. (Contributed by Thierry Arnoux, 2-Apr-2025.) |
| ⊢ 𝐴 = (Base‘𝑅) & ⊢ 𝑆 = (𝑅 ↾s 𝐵) & ⊢ (𝜑 → 𝐵 ⊆ 𝐴) & ⊢ (𝜑 → 𝐶 ⊆ 𝐵) & ⊢ (𝜑 → 𝑅 ∈ 𝑉) ⇒ ⊢ (𝜑 → ((subringAlg ‘𝑆)‘𝐶) = (((subringAlg ‘𝑅)‘𝐶) ↾s 𝐵)) | ||
| Theorem | lsssra 34009 | A subring is a subspace of the subring algebra. (Contributed by Thierry Arnoux, 2-Apr-2025.) |
| ⊢ 𝑊 = ((subringAlg ‘𝑅)‘𝐶) & ⊢ 𝐴 = (Base‘𝑅) & ⊢ 𝑆 = (𝑅 ↾s 𝐵) & ⊢ (𝜑 → 𝐵 ∈ (SubRing‘𝑅)) & ⊢ (𝜑 → 𝐶 ∈ (SubRing‘𝑆)) ⇒ ⊢ (𝜑 → 𝐵 ∈ (LSubSp‘𝑊)) | ||
| Theorem | srapwov 34010 | The "power" operation on a subring algebra. (Contributed by Thierry Arnoux, 10-Jan-2026.) |
| ⊢ 𝐴 = ((subringAlg ‘𝑊)‘𝑆) & ⊢ (𝜑 → 𝑊 ∈ Ring) & ⊢ (𝜑 → 𝑆 ⊆ (Base‘𝑊)) ⇒ ⊢ (𝜑 → (.g‘(mulGrp‘𝑊)) = (.g‘(mulGrp‘𝐴))) | ||
| Theorem | drgext0g 34011 | The additive neutral element of a division ring extension. (Contributed by Thierry Arnoux, 17-Jul-2023.) |
| ⊢ 𝐵 = ((subringAlg ‘𝐸)‘𝑈) & ⊢ (𝜑 → 𝐸 ∈ DivRing) & ⊢ (𝜑 → 𝑈 ∈ (SubRing‘𝐸)) ⇒ ⊢ (𝜑 → (0g‘𝐸) = (0g‘𝐵)) | ||
| Theorem | drgextvsca 34012 | The scalar multiplication operation of a division ring extension. (Contributed by Thierry Arnoux, 17-Jul-2023.) |
| ⊢ 𝐵 = ((subringAlg ‘𝐸)‘𝑈) & ⊢ (𝜑 → 𝐸 ∈ DivRing) & ⊢ (𝜑 → 𝑈 ∈ (SubRing‘𝐸)) ⇒ ⊢ (𝜑 → (.r‘𝐸) = ( ·𝑠 ‘𝐵)) | ||
| Theorem | drgext0gsca 34013 | The additive neutral element of the scalar field of a division ring extension. (Contributed by Thierry Arnoux, 17-Jul-2023.) |
| ⊢ 𝐵 = ((subringAlg ‘𝐸)‘𝑈) & ⊢ (𝜑 → 𝐸 ∈ DivRing) & ⊢ (𝜑 → 𝑈 ∈ (SubRing‘𝐸)) ⇒ ⊢ (𝜑 → (0g‘𝐵) = (0g‘(Scalar‘𝐵))) | ||
| Theorem | drgextsubrg 34014 | The scalar field is a subring of a division ring extension. (Contributed by Thierry Arnoux, 17-Jul-2023.) |
| ⊢ 𝐵 = ((subringAlg ‘𝐸)‘𝑈) & ⊢ (𝜑 → 𝐸 ∈ DivRing) & ⊢ (𝜑 → 𝑈 ∈ (SubRing‘𝐸)) & ⊢ 𝐹 = (𝐸 ↾s 𝑈) & ⊢ (𝜑 → 𝐹 ∈ DivRing) ⇒ ⊢ (𝜑 → 𝑈 ∈ (SubRing‘𝐵)) | ||
| Theorem | drgextlsp 34015 | The scalar field is a subspace of a subring algebra. (Contributed by Thierry Arnoux, 17-Jul-2023.) |
| ⊢ 𝐵 = ((subringAlg ‘𝐸)‘𝑈) & ⊢ (𝜑 → 𝐸 ∈ DivRing) & ⊢ (𝜑 → 𝑈 ∈ (SubRing‘𝐸)) & ⊢ 𝐹 = (𝐸 ↾s 𝑈) & ⊢ (𝜑 → 𝐹 ∈ DivRing) ⇒ ⊢ (𝜑 → 𝑈 ∈ (LSubSp‘𝐵)) | ||
| Theorem | drgextgsum 34016* | Group sum in a division ring extension. (Contributed by Thierry Arnoux, 17-Jul-2023.) |
| ⊢ 𝐵 = ((subringAlg ‘𝐸)‘𝑈) & ⊢ (𝜑 → 𝐸 ∈ DivRing) & ⊢ (𝜑 → 𝑈 ∈ (SubRing‘𝐸)) & ⊢ 𝐹 = (𝐸 ↾s 𝑈) & ⊢ (𝜑 → 𝐹 ∈ DivRing) & ⊢ (𝜑 → 𝑋 ∈ 𝑉) ⇒ ⊢ (𝜑 → (𝐸 Σg (𝑖 ∈ 𝑋 ↦ 𝑌)) = (𝐵 Σg (𝑖 ∈ 𝑋 ↦ 𝑌))) | ||
| Theorem | lvecdimfi 34017 | Finite version of lvecdim 21318 which does not require the axiom of choice. The axiom of choice is used in acsmapd 18635, which is required in the infinite case. Suggested by Gérard Lang. (Contributed by Thierry Arnoux, 24-May-2023.) |
| ⊢ 𝐽 = (LBasis‘𝑊) & ⊢ (𝜑 → 𝑊 ∈ LVec) & ⊢ (𝜑 → 𝑆 ∈ 𝐽) & ⊢ (𝜑 → 𝑇 ∈ 𝐽) & ⊢ (𝜑 → 𝑆 ∈ Fin) ⇒ ⊢ (𝜑 → 𝑆 ≈ 𝑇) | ||
| Theorem | exsslsb 34018* | Any finite generating set 𝑆 of a vector space 𝑊 contains a basis. (Contributed by Thierry Arnoux, 13-Oct-2025.) |
| ⊢ 𝐵 = (Base‘𝑊) & ⊢ 𝐽 = (LBasis‘𝑊) & ⊢ 𝐾 = (LSpan‘𝑊) & ⊢ (𝜑 → 𝑊 ∈ LVec) & ⊢ (𝜑 → 𝑆 ∈ Fin) & ⊢ (𝜑 → 𝑆 ⊆ 𝐵) & ⊢ (𝜑 → (𝐾‘𝑆) = 𝐵) ⇒ ⊢ (𝜑 → ∃𝑠 ∈ 𝐽 𝑠 ⊆ 𝑆) | ||
| Theorem | lbslelsp 34019 | The size of a basis 𝑋 of a vector space 𝑊 is less than the size of a generating set 𝑌. (Contributed by Thierry Arnoux, 13-Oct-2025.) |
| ⊢ 𝐵 = (Base‘𝑊) & ⊢ 𝐽 = (LBasis‘𝑊) & ⊢ 𝐾 = (LSpan‘𝑊) & ⊢ (𝜑 → 𝑊 ∈ LVec) & ⊢ (𝜑 → 𝑋 ∈ 𝐽) & ⊢ (𝜑 → 𝑌 ⊆ 𝐵) & ⊢ (𝜑 → (𝐾‘𝑌) = 𝐵) ⇒ ⊢ (𝜑 → (♯‘𝑋) ≤ (♯‘𝑌)) | ||
| Syntax | cldim 34020 | Extend class notation with the dimension of a vector space. |
| class dim | ||
| Definition | df-dim 34021 | Define the dimension of a vector space as the cardinality of its bases. Note that by lvecdim 21318, all bases are equinumerous. (Contributed by Thierry Arnoux, 6-May-2023.) |
| ⊢ dim = (𝑓 ∈ V ↦ ∪ (♯ “ (LBasis‘𝑓))) | ||
| Theorem | dimval 34022 | The dimension of a vector space 𝐹 is the cardinality of one of its bases. (Contributed by Thierry Arnoux, 6-May-2023.) |
| ⊢ 𝐽 = (LBasis‘𝐹) ⇒ ⊢ ((𝐹 ∈ LVec ∧ 𝑆 ∈ 𝐽) → (dim‘𝐹) = (♯‘𝑆)) | ||
| Theorem | dimvalfi 34023 | The dimension of a vector space 𝐹 is the cardinality of one of its bases. This version of dimval 34022 does not depend on the axiom of choice, but it is limited to the case where the base 𝑆 is finite. (Contributed by Thierry Arnoux, 24-May-2023.) |
| ⊢ 𝐽 = (LBasis‘𝐹) ⇒ ⊢ ((𝐹 ∈ LVec ∧ 𝑆 ∈ 𝐽 ∧ 𝑆 ∈ Fin) → (dim‘𝐹) = (♯‘𝑆)) | ||
| Theorem | dimcl 34024 | Closure of the vector space dimension. (Contributed by Thierry Arnoux, 18-May-2023.) |
| ⊢ (𝑉 ∈ LVec → (dim‘𝑉) ∈ ℕ0*) | ||
| Theorem | lmimdim 34025 | Module isomorphisms preserve vector space dimensions. (Contributed by Thierry Arnoux, 25-Feb-2025.) |
| ⊢ (𝜑 → 𝐹 ∈ (𝑆 LMIso 𝑇)) & ⊢ (𝜑 → 𝑆 ∈ LVec) ⇒ ⊢ (𝜑 → (dim‘𝑆) = (dim‘𝑇)) | ||
| Theorem | lmicdim 34026 | Module isomorphisms preserve vector space dimensions. (Contributed by Thierry Arnoux, 25-Mar-2025.) |
| ⊢ (𝜑 → 𝑆 ≃𝑚 𝑇) & ⊢ (𝜑 → 𝑆 ∈ LVec) ⇒ ⊢ (𝜑 → (dim‘𝑆) = (dim‘𝑇)) | ||
| Theorem | lvecdim0i 34027 | A vector space of dimension zero is reduced to its identity element. (Contributed by Thierry Arnoux, 31-Jul-2023.) |
| ⊢ 0 = (0g‘𝑉) ⇒ ⊢ ((𝑉 ∈ LVec ∧ (dim‘𝑉) = 0) → (Base‘𝑉) = { 0 }) | ||
| Theorem | lvecdim0 34028 | A vector space of dimension zero is reduced to its identity element, biconditional version. (Contributed by Thierry Arnoux, 31-Jul-2023.) |
| ⊢ 0 = (0g‘𝑉) ⇒ ⊢ (𝑉 ∈ LVec → ((dim‘𝑉) = 0 ↔ (Base‘𝑉) = { 0 })) | ||
| Theorem | lssdimle 34029 | The dimension of a linear subspace is less than or equal to the dimension of the parent vector space. This is corollary 5.4 of [Lang] p. 141. (Contributed by Thierry Arnoux, 20-May-2023.) |
| ⊢ 𝑋 = (𝑊 ↾s 𝑈) ⇒ ⊢ ((𝑊 ∈ LVec ∧ 𝑈 ∈ (LSubSp‘𝑊)) → (dim‘𝑋) ≤ (dim‘𝑊)) | ||
| Theorem | dimpropd 34030* | If two structures have the same components (properties), they have the same dimension. (Contributed by Thierry Arnoux, 18-May-2023.) |
| ⊢ (𝜑 → 𝐵 = (Base‘𝐾)) & ⊢ (𝜑 → 𝐵 = (Base‘𝐿)) & ⊢ (𝜑 → 𝐵 ⊆ 𝑊) & ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑊 ∧ 𝑦 ∈ 𝑊)) → (𝑥(+g‘𝐾)𝑦) = (𝑥(+g‘𝐿)𝑦)) & ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑃 ∧ 𝑦 ∈ 𝐵)) → (𝑥( ·𝑠 ‘𝐾)𝑦) ∈ 𝑊) & ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑃 ∧ 𝑦 ∈ 𝐵)) → (𝑥( ·𝑠 ‘𝐾)𝑦) = (𝑥( ·𝑠 ‘𝐿)𝑦)) & ⊢ 𝐹 = (Scalar‘𝐾) & ⊢ 𝐺 = (Scalar‘𝐿) & ⊢ (𝜑 → 𝑃 = (Base‘𝐹)) & ⊢ (𝜑 → 𝑃 = (Base‘𝐺)) & ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑃 ∧ 𝑦 ∈ 𝑃)) → (𝑥(+g‘𝐹)𝑦) = (𝑥(+g‘𝐺)𝑦)) & ⊢ (𝜑 → 𝐾 ∈ LVec) & ⊢ (𝜑 → 𝐿 ∈ LVec) ⇒ ⊢ (𝜑 → (dim‘𝐾) = (dim‘𝐿)) | ||
| Theorem | rlmdim 34031 | The left vector space induced by a ring over itself has dimension 1. (Contributed by Thierry Arnoux, 5-Aug-2023.) Generalize to division rings. (Revised by SN, 22-Mar-2025.) |
| ⊢ 𝑉 = (ringLMod‘𝐹) ⇒ ⊢ (𝐹 ∈ DivRing → (dim‘𝑉) = 1) | ||
| Theorem | frlmdim 34032 | Dimension of a free left module. (Contributed by Thierry Arnoux, 20-May-2023.) |
| ⊢ 𝐹 = (𝑅 freeLMod 𝐼) ⇒ ⊢ ((𝑅 ∈ DivRing ∧ 𝐼 ∈ 𝑉) → (dim‘𝐹) = (♯‘𝐼)) | ||
| Theorem | tnglvec 34033 | Augmenting a structure with a norm conserves left vector spaces. (Contributed by Thierry Arnoux, 20-May-2023.) |
| ⊢ 𝑇 = (𝐺 toNrmGrp 𝑁) ⇒ ⊢ (𝑁 ∈ 𝑉 → (𝐺 ∈ LVec ↔ 𝑇 ∈ LVec)) | ||
| Theorem | tngdim 34034 | Dimension of a left vector space augmented with a norm. (Contributed by Thierry Arnoux, 20-May-2023.) |
| ⊢ 𝑇 = (𝐺 toNrmGrp 𝑁) ⇒ ⊢ ((𝐺 ∈ LVec ∧ 𝑁 ∈ 𝑉) → (dim‘𝐺) = (dim‘𝑇)) | ||
| Theorem | rrxdim 34035 | Dimension of the generalized Euclidean space. (Contributed by Thierry Arnoux, 20-May-2023.) |
| ⊢ 𝐻 = (ℝ^‘𝐼) ⇒ ⊢ (𝐼 ∈ 𝑉 → (dim‘𝐻) = (♯‘𝐼)) | ||
| Theorem | matdim 34036 | Dimension of the space of square matrices. (Contributed by Thierry Arnoux, 20-May-2023.) |
| ⊢ 𝐴 = (𝐼 Mat 𝑅) & ⊢ 𝑁 = (♯‘𝐼) ⇒ ⊢ ((𝐼 ∈ Fin ∧ 𝑅 ∈ DivRing) → (dim‘𝐴) = (𝑁 · 𝑁)) | ||
| Theorem | lbslsat 34037 | A nonzero vector 𝑋 is a basis of a line spanned by the singleton 𝑋. Spans of nonzero singletons are sometimes called "atoms", see df-lsatoms 39791 and for example lsatlspsn 39808. (Contributed by Thierry Arnoux, 20-May-2023.) |
| ⊢ 𝑉 = (Base‘𝑊) & ⊢ 𝑁 = (LSpan‘𝑊) & ⊢ 0 = (0g‘𝑊) & ⊢ 𝑌 = (𝑊 ↾s (𝑁‘{𝑋})) ⇒ ⊢ ((𝑊 ∈ LVec ∧ 𝑋 ∈ 𝑉 ∧ 𝑋 ≠ 0 ) → {𝑋} ∈ (LBasis‘𝑌)) | ||
| Theorem | lsatdim 34038 | A line, spanned by a nonzero singleton, has dimension 1. (Contributed by Thierry Arnoux, 20-May-2023.) |
| ⊢ 𝑉 = (Base‘𝑊) & ⊢ 𝑁 = (LSpan‘𝑊) & ⊢ 0 = (0g‘𝑊) & ⊢ 𝑌 = (𝑊 ↾s (𝑁‘{𝑋})) ⇒ ⊢ ((𝑊 ∈ LVec ∧ 𝑋 ∈ 𝑉 ∧ 𝑋 ≠ 0 ) → (dim‘𝑌) = 1) | ||
| Theorem | drngdimgt0 34039 | The dimension of a vector space that is also a division ring is greater than zero. (Contributed by Thierry Arnoux, 29-Jul-2023.) |
| ⊢ ((𝐹 ∈ LVec ∧ 𝐹 ∈ DivRing) → 0 < (dim‘𝐹)) | ||
| Theorem | lmhmlvec2 34040 | A homomorphism of left vector spaces has a left vector space as codomain. (Contributed by Thierry Arnoux, 7-May-2023.) |
| ⊢ ((𝑉 ∈ LVec ∧ 𝐹 ∈ (𝑉 LMHom 𝑈)) → 𝑈 ∈ LVec) | ||
| Theorem | kerlmhm 34041 | The kernel of a vector space homomorphism is a vector space itself. (Contributed by Thierry Arnoux, 7-May-2023.) |
| ⊢ 0 = (0g‘𝑈) & ⊢ 𝐾 = (𝑉 ↾s (◡𝐹 “ { 0 })) ⇒ ⊢ ((𝑉 ∈ LVec ∧ 𝐹 ∈ (𝑉 LMHom 𝑈)) → 𝐾 ∈ LVec) | ||
| Theorem | imlmhm 34042 | The image of a vector space homomorphism is a vector space itself. (Contributed by Thierry Arnoux, 7-May-2023.) |
| ⊢ 𝐼 = (𝑈 ↾s ran 𝐹) ⇒ ⊢ ((𝑉 ∈ LVec ∧ 𝐹 ∈ (𝑉 LMHom 𝑈)) → 𝐼 ∈ LVec) | ||
| Theorem | ply1degltdimlem 34043* | Lemma for ply1degltdim 34044. (Contributed by Thierry Arnoux, 20-Feb-2025.) |
| ⊢ 𝑃 = (Poly1‘𝑅) & ⊢ 𝐷 = (deg1‘𝑅) & ⊢ 𝑆 = (◡𝐷 “ (-∞[,)𝑁)) & ⊢ (𝜑 → 𝑁 ∈ ℕ0) & ⊢ (𝜑 → 𝑅 ∈ DivRing) & ⊢ 𝐸 = (𝑃 ↾s 𝑆) & ⊢ 𝐹 = (𝑛 ∈ (0..^𝑁) ↦ (𝑛(.g‘(mulGrp‘𝑃))(var1‘𝑅))) ⇒ ⊢ (𝜑 → ran 𝐹 ∈ (LBasis‘𝐸)) | ||
| Theorem | ply1degltdim 34044 | The space 𝑆 of the univariate polynomials of degree less than 𝑁 has dimension 𝑁. (Contributed by Thierry Arnoux, 20-Feb-2025.) |
| ⊢ 𝑃 = (Poly1‘𝑅) & ⊢ 𝐷 = (deg1‘𝑅) & ⊢ 𝑆 = (◡𝐷 “ (-∞[,)𝑁)) & ⊢ (𝜑 → 𝑁 ∈ ℕ0) & ⊢ (𝜑 → 𝑅 ∈ DivRing) & ⊢ 𝐸 = (𝑃 ↾s 𝑆) ⇒ ⊢ (𝜑 → (dim‘𝐸) = 𝑁) | ||
| Theorem | lindsunlem 34045 | Lemma for lindsun 34046. (Contributed by Thierry Arnoux, 9-May-2023.) |
| ⊢ 𝑁 = (LSpan‘𝑊) & ⊢ 0 = (0g‘𝑊) & ⊢ (𝜑 → 𝑊 ∈ LVec) & ⊢ (𝜑 → 𝑈 ∈ (LIndS‘𝑊)) & ⊢ (𝜑 → 𝑉 ∈ (LIndS‘𝑊)) & ⊢ (𝜑 → ((𝑁‘𝑈) ∩ (𝑁‘𝑉)) = { 0 }) & ⊢ 𝑂 = (0g‘(Scalar‘𝑊)) & ⊢ 𝐹 = (Base‘(Scalar‘𝑊)) & ⊢ (𝜑 → 𝐶 ∈ 𝑈) & ⊢ (𝜑 → 𝐾 ∈ (𝐹 ∖ {𝑂})) & ⊢ (𝜑 → (𝐾( ·𝑠 ‘𝑊)𝐶) ∈ (𝑁‘((𝑈 ∪ 𝑉) ∖ {𝐶}))) ⇒ ⊢ (𝜑 → ⊥) | ||
| Theorem | lindsun 34046 | Condition for the union of two independent sets to be an independent set. (Contributed by Thierry Arnoux, 9-May-2023.) |
| ⊢ 𝑁 = (LSpan‘𝑊) & ⊢ 0 = (0g‘𝑊) & ⊢ (𝜑 → 𝑊 ∈ LVec) & ⊢ (𝜑 → 𝑈 ∈ (LIndS‘𝑊)) & ⊢ (𝜑 → 𝑉 ∈ (LIndS‘𝑊)) & ⊢ (𝜑 → ((𝑁‘𝑈) ∩ (𝑁‘𝑉)) = { 0 }) ⇒ ⊢ (𝜑 → (𝑈 ∪ 𝑉) ∈ (LIndS‘𝑊)) | ||
| Theorem | lbsdiflsp0 34047 | The linear spans of two disjunct independent sets only have a trivial intersection. This can be seen as the opposite direction of lindsun 34046. (Contributed by Thierry Arnoux, 17-May-2023.) |
| ⊢ 𝐽 = (LBasis‘𝑊) & ⊢ 𝑁 = (LSpan‘𝑊) & ⊢ 0 = (0g‘𝑊) ⇒ ⊢ ((𝑊 ∈ LVec ∧ 𝐵 ∈ 𝐽 ∧ 𝑉 ⊆ 𝐵) → ((𝑁‘(𝐵 ∖ 𝑉)) ∩ (𝑁‘𝑉)) = { 0 }) | ||
| Theorem | dimkerim 34048 | Given a linear map 𝐹 between vector spaces 𝑉 and 𝑈, the dimension of the vector space 𝑉 is the sum of the dimension of 𝐹 's kernel and the dimension of 𝐹's image. Second part of theorem 5.3 in [Lang] p. 141 This can also be described as the Rank-nullity theorem, (dim‘𝐼) being the rank of 𝐹 (the dimension of its image), and (dim‘𝐾) its nullity (the dimension of its kernel). (Contributed by Thierry Arnoux, 17-May-2023.) |
| ⊢ 0 = (0g‘𝑈) & ⊢ 𝐾 = (𝑉 ↾s (◡𝐹 “ { 0 })) & ⊢ 𝐼 = (𝑈 ↾s ran 𝐹) ⇒ ⊢ ((𝑉 ∈ LVec ∧ 𝐹 ∈ (𝑉 LMHom 𝑈)) → (dim‘𝑉) = ((dim‘𝐾) +𝑒 (dim‘𝐼))) | ||
| Theorem | qusdimsum 34049 | Let 𝑊 be a vector space, and let 𝑋 be a subspace. Then the dimension of 𝑊 is the sum of the dimension of 𝑋 and the dimension of the quotient space of 𝑋. First part of theorem 5.3 in [Lang] p. 141. (Contributed by Thierry Arnoux, 20-May-2023.) |
| ⊢ 𝑋 = (𝑊 ↾s 𝑈) & ⊢ 𝑌 = (𝑊 /s (𝑊 ~QG 𝑈)) ⇒ ⊢ ((𝑊 ∈ LVec ∧ 𝑈 ∈ (LSubSp‘𝑊)) → (dim‘𝑊) = ((dim‘𝑋) +𝑒 (dim‘𝑌))) | ||
| Theorem | fedgmullem1 34050* | Lemma for fedgmul 34052. (Contributed by Thierry Arnoux, 20-Jul-2023.) |
| ⊢ 𝐴 = ((subringAlg ‘𝐸)‘𝑉) & ⊢ 𝐵 = ((subringAlg ‘𝐸)‘𝑈) & ⊢ 𝐶 = ((subringAlg ‘𝐹)‘𝑉) & ⊢ 𝐹 = (𝐸 ↾s 𝑈) & ⊢ 𝐾 = (𝐸 ↾s 𝑉) & ⊢ (𝜑 → 𝐸 ∈ DivRing) & ⊢ (𝜑 → 𝐹 ∈ DivRing) & ⊢ (𝜑 → 𝐾 ∈ DivRing) & ⊢ (𝜑 → 𝑈 ∈ (SubRing‘𝐸)) & ⊢ (𝜑 → 𝑉 ∈ (SubRing‘𝐹)) & ⊢ 𝐷 = (𝑗 ∈ 𝑌, 𝑖 ∈ 𝑋 ↦ (𝑖(.r‘𝐸)𝑗)) & ⊢ 𝐻 = (𝑗 ∈ 𝑌, 𝑖 ∈ 𝑋 ↦ ((𝐺‘𝑗)‘𝑖)) & ⊢ (𝜑 → 𝑋 ∈ (LBasis‘𝐶)) & ⊢ (𝜑 → 𝑌 ∈ (LBasis‘𝐵)) & ⊢ (𝜑 → 𝑍 ∈ (Base‘𝐴)) & ⊢ (𝜑 → 𝐿:𝑌⟶(Base‘(Scalar‘𝐵))) & ⊢ (𝜑 → 𝐿 finSupp (0g‘(Scalar‘𝐵))) & ⊢ (𝜑 → 𝑍 = (𝐵 Σg (𝑗 ∈ 𝑌 ↦ ((𝐿‘𝑗)( ·𝑠 ‘𝐵)𝑗)))) & ⊢ (𝜑 → 𝐺:𝑌⟶((Base‘(Scalar‘𝐶)) ↑m 𝑋)) & ⊢ ((𝜑 ∧ 𝑗 ∈ 𝑌) → (𝐺‘𝑗) finSupp (0g‘(Scalar‘𝐶))) & ⊢ ((𝜑 ∧ 𝑗 ∈ 𝑌) → (𝐿‘𝑗) = (𝐶 Σg (𝑖 ∈ 𝑋 ↦ (((𝐺‘𝑗)‘𝑖)( ·𝑠 ‘𝐶)𝑖)))) ⇒ ⊢ (𝜑 → (𝐻 finSupp (0g‘(Scalar‘𝐴)) ∧ 𝑍 = (𝐴 Σg (𝐻 ∘f ( ·𝑠 ‘𝐴)𝐷)))) | ||
| Theorem | fedgmullem2 34051* | Lemma for fedgmul 34052. (Contributed by Thierry Arnoux, 20-Jul-2023.) |
| ⊢ 𝐴 = ((subringAlg ‘𝐸)‘𝑉) & ⊢ 𝐵 = ((subringAlg ‘𝐸)‘𝑈) & ⊢ 𝐶 = ((subringAlg ‘𝐹)‘𝑉) & ⊢ 𝐹 = (𝐸 ↾s 𝑈) & ⊢ 𝐾 = (𝐸 ↾s 𝑉) & ⊢ (𝜑 → 𝐸 ∈ DivRing) & ⊢ (𝜑 → 𝐹 ∈ DivRing) & ⊢ (𝜑 → 𝐾 ∈ DivRing) & ⊢ (𝜑 → 𝑈 ∈ (SubRing‘𝐸)) & ⊢ (𝜑 → 𝑉 ∈ (SubRing‘𝐹)) & ⊢ 𝐷 = (𝑗 ∈ 𝑌, 𝑖 ∈ 𝑋 ↦ (𝑖(.r‘𝐸)𝑗)) & ⊢ 𝐻 = (𝑗 ∈ 𝑌, 𝑖 ∈ 𝑋 ↦ ((𝐺‘𝑗)‘𝑖)) & ⊢ (𝜑 → 𝑋 ∈ (LBasis‘𝐶)) & ⊢ (𝜑 → 𝑌 ∈ (LBasis‘𝐵)) & ⊢ (𝜑 → 𝑊 ∈ (Base‘((Scalar‘𝐴) freeLMod (𝑌 × 𝑋)))) & ⊢ (𝜑 → (𝐴 Σg (𝑊 ∘f ( ·𝑠 ‘𝐴)𝐷)) = (0g‘𝐴)) ⇒ ⊢ (𝜑 → 𝑊 = ((𝑌 × 𝑋) × {(0g‘(Scalar‘𝐴))})) | ||
| Theorem | fedgmul 34052 | The multiplicativity formula for degrees of field extensions. Given 𝐸 a field extension of 𝐹, itself a field extension of 𝐾, we have [𝐸:𝐾] = [𝐸:𝐹][𝐹:𝐾]. Proposition 1.2 of [Lang], p. 224. Here (dim‘𝐴) is the degree of the extension 𝐸 of 𝐾, (dim‘𝐵) is the degree of the extension 𝐸 of 𝐹, and (dim‘𝐶) is the degree of the extension 𝐹 of 𝐾. This proof is valid for infinite dimensions, and is actually valid for division ring extensions, not just field extensions. (Contributed by Thierry Arnoux, 25-Jul-2023.) |
| ⊢ 𝐴 = ((subringAlg ‘𝐸)‘𝑉) & ⊢ 𝐵 = ((subringAlg ‘𝐸)‘𝑈) & ⊢ 𝐶 = ((subringAlg ‘𝐹)‘𝑉) & ⊢ 𝐹 = (𝐸 ↾s 𝑈) & ⊢ 𝐾 = (𝐸 ↾s 𝑉) & ⊢ (𝜑 → 𝐸 ∈ DivRing) & ⊢ (𝜑 → 𝐹 ∈ DivRing) & ⊢ (𝜑 → 𝐾 ∈ DivRing) & ⊢ (𝜑 → 𝑈 ∈ (SubRing‘𝐸)) & ⊢ (𝜑 → 𝑉 ∈ (SubRing‘𝐹)) ⇒ ⊢ (𝜑 → (dim‘𝐴) = ((dim‘𝐵) ·e (dim‘𝐶))) | ||
| Theorem | dimlssid 34053 | If the dimension of a linear subspace 𝐿 is the dimension of the whole vector space 𝐸, then 𝐿 is the whole space. (Contributed by Thierry Arnoux, 3-Aug-2025.) |
| ⊢ 𝐵 = (Base‘𝐸) & ⊢ (𝜑 → 𝐸 ∈ LVec) & ⊢ (𝜑 → (dim‘𝐸) ∈ ℕ0) & ⊢ (𝜑 → 𝐿 ∈ (LSubSp‘𝐸)) & ⊢ (𝜑 → (dim‘(𝐸 ↾s 𝐿)) = (dim‘𝐸)) ⇒ ⊢ (𝜑 → 𝐿 = 𝐵) | ||
| Theorem | lvecendof1f1o 34054 | If an endomorphism 𝑈 of a vector space 𝐸 of finite dimension is injective, then it is bijective. Item (b) of Corollary of Proposition 9 in [BourbakiAlg1] p. 298 . (Contributed by Thierry Arnoux, 3-Aug-2025.) |
| ⊢ 𝐵 = (Base‘𝐸) & ⊢ (𝜑 → 𝐸 ∈ LVec) & ⊢ (𝜑 → (dim‘𝐸) ∈ ℕ0) & ⊢ (𝜑 → 𝑈 ∈ (𝐸 LMHom 𝐸)) & ⊢ (𝜑 → 𝑈:𝐵–1-1→𝐵) ⇒ ⊢ (𝜑 → 𝑈:𝐵–1-1-onto→𝐵) | ||
| Theorem | lactlmhm 34055* | In an associative algebra 𝐴, left-multiplication by a fixed element of the algebra is a module homomorphism, analogous to ringlghm 20428. (Contributed by Thierry Arnoux, 3-Aug-2025.) |
| ⊢ 𝐵 = (Base‘𝐴) & ⊢ · = (.r‘𝐴) & ⊢ 𝐹 = (𝑥 ∈ 𝐵 ↦ (𝐶 · 𝑥)) & ⊢ (𝜑 → 𝐴 ∈ AssAlg) & ⊢ (𝜑 → 𝐶 ∈ 𝐵) ⇒ ⊢ (𝜑 → 𝐹 ∈ (𝐴 LMHom 𝐴)) | ||
| Theorem | assalactf1o 34056* | In an associative algebra 𝐴, left-multiplication by a fixed element of the algebra is bijective. See also lactlmhm 34055. (Contributed by Thierry Arnoux, 3-Aug-2025.) |
| ⊢ 𝐵 = (Base‘𝐴) & ⊢ · = (.r‘𝐴) & ⊢ 𝐹 = (𝑥 ∈ 𝐵 ↦ (𝐶 · 𝑥)) & ⊢ (𝜑 → 𝐴 ∈ AssAlg) & ⊢ 𝐸 = (RLReg‘𝐴) & ⊢ 𝐾 = (Scalar‘𝐴) & ⊢ (𝜑 → 𝐾 ∈ DivRing) & ⊢ (𝜑 → (dim‘𝐴) ∈ ℕ0) & ⊢ (𝜑 → 𝐶 ∈ 𝐸) ⇒ ⊢ (𝜑 → 𝐹:𝐵–1-1-onto→𝐵) | ||
| Theorem | assarrginv 34057 | If an element 𝑋 of an associative algebra 𝐴 over a division ring 𝐾 is regular, then it is a unit. Proposition 2. in Chapter 5. of [BourbakiAlg2] p. 113. (Contributed by Thierry Arnoux, 3-Aug-2025.) |
| ⊢ 𝐸 = (RLReg‘𝐴) & ⊢ 𝑈 = (Unit‘𝐴) & ⊢ 𝐾 = (Scalar‘𝐴) & ⊢ (𝜑 → 𝐴 ∈ AssAlg) & ⊢ (𝜑 → 𝐾 ∈ DivRing) & ⊢ (𝜑 → (dim‘𝐴) ∈ ℕ0) & ⊢ (𝜑 → 𝑋 ∈ 𝐸) ⇒ ⊢ (𝜑 → 𝑋 ∈ 𝑈) | ||
| Theorem | assafld 34058 | If an algebra 𝐴 of finite degree over a division ring 𝐾 is an integral domain, then it is a field. Corollary of Proposition 2. in Chapter 5. of [BourbakiAlg2] p. 113. (Contributed by Thierry Arnoux, 3-Aug-2025.) |
| ⊢ 𝐾 = (Scalar‘𝐴) & ⊢ (𝜑 → 𝐴 ∈ AssAlg) & ⊢ (𝜑 → 𝐴 ∈ IDomn) & ⊢ (𝜑 → 𝐾 ∈ DivRing) & ⊢ (𝜑 → (dim‘𝐴) ∈ ℕ0) ⇒ ⊢ (𝜑 → 𝐴 ∈ Field) | ||
| Syntax | cfldext 34059 | Syntax for the field extension relation. |
| class /FldExt | ||
| Syntax | cfinext 34060 | Syntax for the finite field extension relation. |
| class /FinExt | ||
| Syntax | cextdg 34061 | Syntax for the field extension degree operation. |
| class [:] | ||
| Definition | df-fldext 34062* | Definition of the field extension relation. (Contributed by Thierry Arnoux, 29-Jul-2023.) |
| ⊢ /FldExt = {⟨𝑒, 𝑓⟩ ∣ ((𝑒 ∈ Field ∧ 𝑓 ∈ Field) ∧ (𝑓 = (𝑒 ↾s (Base‘𝑓)) ∧ (Base‘𝑓) ∈ (SubRing‘𝑒)))} | ||
| Definition | df-extdg 34063* | Definition of the field extension degree operation. (Contributed by Thierry Arnoux, 29-Jul-2023.) |
| ⊢ [:] = (𝑒 ∈ V, 𝑓 ∈ (/FldExt “ {𝑒}) ↦ (dim‘((subringAlg ‘𝑒)‘(Base‘𝑓)))) | ||
| Definition | df-finext 34064* | Definition of the finite field extension relation. (Contributed by Thierry Arnoux, 29-Jul-2023.) |
| ⊢ /FinExt = {⟨𝑒, 𝑓⟩ ∣ (𝑒/FldExt𝑓 ∧ (𝑒[:]𝑓) ∈ ℕ0)} | ||
| Theorem | relfldext 34065 | The field extension is a relation. (Contributed by Thierry Arnoux, 29-Jul-2023.) |
| ⊢ Rel /FldExt | ||
| Theorem | brfldext 34066 | The field extension relation explicited. (Contributed by Thierry Arnoux, 29-Jul-2023.) |
| ⊢ ((𝐸 ∈ Field ∧ 𝐹 ∈ Field) → (𝐸/FldExt𝐹 ↔ (𝐹 = (𝐸 ↾s (Base‘𝐹)) ∧ (Base‘𝐹) ∈ (SubRing‘𝐸)))) | ||
| Theorem | ccfldextrr 34067 | The field of the complex numbers is an extension of the field of the real numbers. (Contributed by Thierry Arnoux, 20-Jul-2023.) |
| ⊢ ℂfld/FldExtℝfld | ||
| Theorem | fldextfld1 34068 | A field extension is only defined if the extension is a field. (Contributed by Thierry Arnoux, 29-Jul-2023.) |
| ⊢ (𝐸/FldExt𝐹 → 𝐸 ∈ Field) | ||
| Theorem | fldextfld2 34069 | A field extension is only defined if the subfield is a field. (Contributed by Thierry Arnoux, 29-Jul-2023.) |
| ⊢ (𝐸/FldExt𝐹 → 𝐹 ∈ Field) | ||
| Theorem | fldextsubrg 34070 | Field extension implies a subring relation. (Contributed by Thierry Arnoux, 29-Jul-2023.) |
| ⊢ 𝑈 = (Base‘𝐹) ⇒ ⊢ (𝐸/FldExt𝐹 → 𝑈 ∈ (SubRing‘𝐸)) | ||
| Theorem | sdrgfldext 34071 | A field 𝐸 and any sub-division-ring 𝐹 of 𝐸 form a field extension. (Contributed by Thierry Arnoux, 26-Oct-2025.) |
| ⊢ 𝐵 = (Base‘𝐸) & ⊢ (𝜑 → 𝐸 ∈ Field) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐸)) ⇒ ⊢ (𝜑 → 𝐸/FldExt(𝐸 ↾s 𝐹)) | ||
| Theorem | fldextress 34072 | Field extension implies a structure restriction relation. (Contributed by Thierry Arnoux, 29-Jul-2023.) |
| ⊢ (𝐸/FldExt𝐹 → 𝐹 = (𝐸 ↾s (Base‘𝐹))) | ||
| Theorem | brfinext 34073 | The finite field extension relation explicited. (Contributed by Thierry Arnoux, 29-Jul-2023.) |
| ⊢ (𝐸/FldExt𝐹 → (𝐸/FinExt𝐹 ↔ (𝐸[:]𝐹) ∈ ℕ0)) | ||
| Theorem | extdgval 34074 | Value of the field extension degree operation. (Contributed by Thierry Arnoux, 29-Jul-2023.) |
| ⊢ (𝐸/FldExt𝐹 → (𝐸[:]𝐹) = (dim‘((subringAlg ‘𝐸)‘(Base‘𝐹)))) | ||
| Theorem | fldextsdrg 34075 | Deduce sub-division-ring from field extension. (Contributed by Thierry Arnoux, 26-Oct-2025.) |
| ⊢ 𝐵 = (Base‘𝐹) & ⊢ (𝜑 → 𝐸/FldExt𝐹) ⇒ ⊢ (𝜑 → 𝐵 ∈ (SubDRing‘𝐸)) | ||
| Theorem | fldextsralvec 34076 | The subring algebra associated with a field extension is a vector space. (Contributed by Thierry Arnoux, 3-Aug-2023.) |
| ⊢ (𝐸/FldExt𝐹 → ((subringAlg ‘𝐸)‘(Base‘𝐹)) ∈ LVec) | ||
| Theorem | extdgcl 34077 | Closure of the field extension degree operation. (Contributed by Thierry Arnoux, 29-Jul-2023.) |
| ⊢ (𝐸/FldExt𝐹 → (𝐸[:]𝐹) ∈ ℕ0*) | ||
| Theorem | extdggt0 34078 | Degrees of field extension are greater than zero. (Contributed by Thierry Arnoux, 30-Jul-2023.) |
| ⊢ (𝐸/FldExt𝐹 → 0 < (𝐸[:]𝐹)) | ||
| Theorem | fldexttr 34079 | Field extension is a transitive relation. (Contributed by Thierry Arnoux, 29-Jul-2023.) |
| ⊢ ((𝐸/FldExt𝐹 ∧ 𝐹/FldExt𝐾) → 𝐸/FldExt𝐾) | ||
| Theorem | fldextid 34080 | The field extension relation is reflexive. (Contributed by Thierry Arnoux, 30-Jul-2023.) |
| ⊢ (𝐹 ∈ Field → 𝐹/FldExt𝐹) | ||
| Theorem | extdgid 34081 | A trivial field extension has degree one. (Contributed by Thierry Arnoux, 4-Aug-2023.) |
| ⊢ (𝐸 ∈ Field → (𝐸[:]𝐸) = 1) | ||
| Theorem | fldsdrgfldext 34082 | A sub-division-ring of a field forms a field extension. (Contributed by Thierry Arnoux, 19-Oct-2025.) |
| ⊢ 𝐺 = (𝐹 ↾s 𝐴) & ⊢ (𝜑 → 𝐹 ∈ Field) & ⊢ (𝜑 → 𝐴 ∈ (SubDRing‘𝐹)) ⇒ ⊢ (𝜑 → 𝐹/FldExt𝐺) | ||
| Theorem | fldsdrgfldext2 34083 | A sub-sub-division-ring of a field forms a field extension. (Contributed by Thierry Arnoux, 19-Oct-2025.) |
| ⊢ 𝐺 = (𝐹 ↾s 𝐴) & ⊢ (𝜑 → 𝐹 ∈ Field) & ⊢ (𝜑 → 𝐴 ∈ (SubDRing‘𝐹)) & ⊢ (𝜑 → 𝐵 ∈ (SubDRing‘𝐺)) & ⊢ 𝐻 = (𝐹 ↾s 𝐵) ⇒ ⊢ (𝜑 → 𝐺/FldExt𝐻) | ||
| Theorem | extdgmul 34084 | The multiplicativity formula for degrees of field extensions. Given 𝐸 a field extension of 𝐹, itself a field extension of 𝐾, the degree of the extension 𝐸/FldExt𝐾 is the product of the degrees of the extensions 𝐸/FldExt𝐹 and 𝐹/FldExt𝐾. Proposition 1.2 of [Lang], p. 224. (Contributed by Thierry Arnoux, 30-Jul-2023.) |
| ⊢ ((𝐸/FldExt𝐹 ∧ 𝐹/FldExt𝐾) → (𝐸[:]𝐾) = ((𝐸[:]𝐹) ·e (𝐹[:]𝐾))) | ||
| Theorem | finextfldext 34085 | A finite field extension is a field extension. (Contributed by Thierry Arnoux, 10-Jan-2026.) |
| ⊢ (𝜑 → 𝐸/FinExt𝐹) ⇒ ⊢ (𝜑 → 𝐸/FldExt𝐹) | ||
| Theorem | finexttrb 34086 | The extension 𝐸 of 𝐾 is finite if and only if 𝐸 is finite over 𝐹 and 𝐹 is finite over 𝐾. Corollary 1.3 of [Lang] , p. 225. (Contributed by Thierry Arnoux, 30-Jul-2023.) |
| ⊢ ((𝐸/FldExt𝐹 ∧ 𝐹/FldExt𝐾) → (𝐸/FinExt𝐾 ↔ (𝐸/FinExt𝐹 ∧ 𝐹/FinExt𝐾))) | ||
| Theorem | extdg1id 34087 | If the degree of the extension 𝐸/FldExt𝐹 is 1, then 𝐸 and 𝐹 are identical. (Contributed by Thierry Arnoux, 6-Aug-2023.) |
| ⊢ ((𝐸/FldExt𝐹 ∧ (𝐸[:]𝐹) = 1) → 𝐸 = 𝐹) | ||
| Theorem | extdg1b 34088 | The degree of the extension 𝐸/FldExt𝐹 is 1 iff 𝐸 and 𝐹 are the same structure. (Contributed by Thierry Arnoux, 6-Aug-2023.) |
| ⊢ (𝐸/FldExt𝐹 → ((𝐸[:]𝐹) = 1 ↔ 𝐸 = 𝐹)) | ||
| Theorem | fldgenfldext 34089 | A subfield 𝐹 extended with a set 𝐴 forms a field extension. (Contributed by Thierry Arnoux, 22-Jun-2025.) |
| ⊢ 𝐵 = (Base‘𝐸) & ⊢ 𝐾 = (𝐸 ↾s 𝐹) & ⊢ 𝐿 = (𝐸 ↾s (𝐸 fldGen (𝐹 ∪ 𝐴))) & ⊢ (𝜑 → 𝐸 ∈ Field) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐸)) & ⊢ (𝜑 → 𝐴 ⊆ 𝐵) ⇒ ⊢ (𝜑 → 𝐿/FldExt𝐾) | ||
| Theorem | fldextchr 34090 | The characteristic of a subfield is the same as the characteristic of the larger field. (Contributed by Thierry Arnoux, 20-Aug-2023.) |
| ⊢ (𝐸/FldExt𝐹 → (chr‘𝐹) = (chr‘𝐸)) | ||
| Theorem | evls1fldgencl 34091 | Closure of the subring polynomial evaluation in the field extention. (Contributed by Thierry Arnoux, 2-Apr-2025.) |
| ⊢ 𝐵 = (Base‘𝐸) & ⊢ 𝑂 = (𝐸 evalSub1 𝐹) & ⊢ 𝑃 = (Poly1‘(𝐸 ↾s 𝐹)) & ⊢ 𝑈 = (Base‘𝑃) & ⊢ (𝜑 → 𝐸 ∈ Field) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐸)) & ⊢ (𝜑 → 𝐴 ∈ 𝐵) & ⊢ (𝜑 → 𝐺 ∈ 𝑈) ⇒ ⊢ (𝜑 → ((𝑂‘𝐺)‘𝐴) ∈ (𝐸 fldGen (𝐹 ∪ {𝐴}))) | ||
| Theorem | ccfldsrarelvec 34092 | The subring algebra of the complex numbers over the real numbers is a left vector space. (Contributed by Thierry Arnoux, 20-Aug-2023.) |
| ⊢ ((subringAlg ‘ℂfld)‘ℝ) ∈ LVec | ||
| Theorem | ccfldextdgrr 34093 | The degree of the field extension of the complex numbers over the real numbers is 2. (Suggested by GL, 4-Aug-2023.) (Contributed by Thierry Arnoux, 20-Aug-2023.) |
| ⊢ (ℂfld[:]ℝfld) = 2 | ||
| Theorem | fldextrspunlsplem 34094* | Lemma for fldextrspunlsp 34095: First direction. Part of the proof of Proposition 5, Chapter 5, of [BourbakiAlg2] p. 116. (Contributed by Thierry Arnoux, 13-Oct-2025.) |
| ⊢ 𝐾 = (𝐿 ↾s 𝐹) & ⊢ 𝐼 = (𝐿 ↾s 𝐺) & ⊢ 𝐽 = (𝐿 ↾s 𝐻) & ⊢ (𝜑 → 𝐿 ∈ Field) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐼)) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐽)) & ⊢ (𝜑 → 𝐺 ∈ (SubDRing‘𝐿)) & ⊢ (𝜑 → 𝐻 ∈ (SubDRing‘𝐿)) & ⊢ 𝑁 = (RingSpan‘𝐿) & ⊢ 𝐶 = (𝑁‘(𝐺 ∪ 𝐻)) & ⊢ 𝐸 = (𝐿 ↾s 𝐶) & ⊢ (𝜑 → 𝐵 ∈ (LBasis‘((subringAlg ‘𝐽)‘𝐹))) & ⊢ (𝜑 → 𝐵 ∈ Fin) & ⊢ (𝜑 → 𝑃:𝐻⟶𝐺) & ⊢ (𝜑 → 𝑃 finSupp (0g‘𝐿)) & ⊢ (𝜑 → 𝑋 = (𝐿 Σg (𝑓 ∈ 𝐻 ↦ ((𝑃‘𝑓)(.r‘𝐿)𝑓)))) ⇒ ⊢ (𝜑 → ∃𝑎 ∈ (𝐺 ↑m 𝐵)(𝑎 finSupp (0g‘𝐿) ∧ 𝑋 = (𝐿 Σg (𝑏 ∈ 𝐵 ↦ ((𝑎‘𝑏)(.r‘𝐿)𝑏))))) | ||
| Theorem | fldextrspunlsp 34095 | Lemma for fldextrspunfld 34097. The subring generated by the union of two field extensions 𝐺 and 𝐻 is the vector sub- 𝐺 space generated by a basis 𝐵 of 𝐻. Part of the proof of Proposition 5, Chapter 5, of [BourbakiAlg2] p. 116. (Contributed by Thierry Arnoux, 13-Oct-2025.) |
| ⊢ 𝐾 = (𝐿 ↾s 𝐹) & ⊢ 𝐼 = (𝐿 ↾s 𝐺) & ⊢ 𝐽 = (𝐿 ↾s 𝐻) & ⊢ (𝜑 → 𝐿 ∈ Field) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐼)) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐽)) & ⊢ (𝜑 → 𝐺 ∈ (SubDRing‘𝐿)) & ⊢ (𝜑 → 𝐻 ∈ (SubDRing‘𝐿)) & ⊢ 𝑁 = (RingSpan‘𝐿) & ⊢ 𝐶 = (𝑁‘(𝐺 ∪ 𝐻)) & ⊢ 𝐸 = (𝐿 ↾s 𝐶) & ⊢ (𝜑 → 𝐵 ∈ (LBasis‘((subringAlg ‘𝐽)‘𝐹))) & ⊢ (𝜑 → 𝐵 ∈ Fin) ⇒ ⊢ (𝜑 → 𝐶 = ((LSpan‘((subringAlg ‘𝐿)‘𝐺))‘𝐵)) | ||
| Theorem | fldextrspunlem1 34096 | Lemma for fldextrspunfld 34097. Part of the proof of Proposition 5, Chapter 5, of [BourbakiAlg2] p. 116. (Contributed by Thierry Arnoux, 13-Oct-2025.) |
| ⊢ 𝐾 = (𝐿 ↾s 𝐹) & ⊢ 𝐼 = (𝐿 ↾s 𝐺) & ⊢ 𝐽 = (𝐿 ↾s 𝐻) & ⊢ (𝜑 → 𝐿 ∈ Field) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐼)) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐽)) & ⊢ (𝜑 → 𝐺 ∈ (SubDRing‘𝐿)) & ⊢ (𝜑 → 𝐻 ∈ (SubDRing‘𝐿)) & ⊢ (𝜑 → (𝐽[:]𝐾) ∈ ℕ0) & ⊢ 𝑁 = (RingSpan‘𝐿) & ⊢ 𝐶 = (𝑁‘(𝐺 ∪ 𝐻)) & ⊢ 𝐸 = (𝐿 ↾s 𝐶) ⇒ ⊢ (𝜑 → (dim‘((subringAlg ‘𝐸)‘𝐺)) ≤ (𝐽[:]𝐾)) | ||
| Theorem | fldextrspunfld 34097 | The ring generated by the union of two field extensions is a field. Part of the proof of Proposition 5, Chapter 5, of [BourbakiAlg2] p. 116. (Contributed by Thierry Arnoux, 13-Oct-2025.) |
| ⊢ 𝐾 = (𝐿 ↾s 𝐹) & ⊢ 𝐼 = (𝐿 ↾s 𝐺) & ⊢ 𝐽 = (𝐿 ↾s 𝐻) & ⊢ (𝜑 → 𝐿 ∈ Field) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐼)) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐽)) & ⊢ (𝜑 → 𝐺 ∈ (SubDRing‘𝐿)) & ⊢ (𝜑 → 𝐻 ∈ (SubDRing‘𝐿)) & ⊢ (𝜑 → (𝐽[:]𝐾) ∈ ℕ0) & ⊢ 𝑁 = (RingSpan‘𝐿) & ⊢ 𝐶 = (𝑁‘(𝐺 ∪ 𝐻)) & ⊢ 𝐸 = (𝐿 ↾s 𝐶) ⇒ ⊢ (𝜑 → 𝐸 ∈ Field) | ||
| Theorem | fldextrspunlem2 34098 | Part of the proof of Proposition 5, Chapter 5, of [BourbakiAlg2] p. 116. (Contributed by Thierry Arnoux, 13-Oct-2025.) |
| ⊢ 𝐾 = (𝐿 ↾s 𝐹) & ⊢ 𝐼 = (𝐿 ↾s 𝐺) & ⊢ 𝐽 = (𝐿 ↾s 𝐻) & ⊢ (𝜑 → 𝐿 ∈ Field) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐼)) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐽)) & ⊢ (𝜑 → 𝐺 ∈ (SubDRing‘𝐿)) & ⊢ (𝜑 → 𝐻 ∈ (SubDRing‘𝐿)) & ⊢ (𝜑 → (𝐽[:]𝐾) ∈ ℕ0) & ⊢ 𝑁 = (RingSpan‘𝐿) & ⊢ 𝐶 = (𝑁‘(𝐺 ∪ 𝐻)) & ⊢ 𝐸 = (𝐿 ↾s 𝐶) ⇒ ⊢ (𝜑 → 𝐶 = (𝐿 fldGen (𝐺 ∪ 𝐻))) | ||
| Theorem | fldextrspundgle 34099 | Inequality involving the degree of two different field extensions 𝐼 and 𝐽 of a same field 𝐹. Part of the proof of Proposition 5, Chapter 5, of [BourbakiAlg2] p. 116. (Contributed by Thierry Arnoux, 13-Oct-2025.) |
| ⊢ 𝐾 = (𝐿 ↾s 𝐹) & ⊢ 𝐼 = (𝐿 ↾s 𝐺) & ⊢ 𝐽 = (𝐿 ↾s 𝐻) & ⊢ (𝜑 → 𝐿 ∈ Field) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐼)) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐽)) & ⊢ (𝜑 → 𝐺 ∈ (SubDRing‘𝐿)) & ⊢ (𝜑 → 𝐻 ∈ (SubDRing‘𝐿)) & ⊢ (𝜑 → (𝐽[:]𝐾) ∈ ℕ0) & ⊢ 𝐸 = (𝐿 ↾s (𝐿 fldGen (𝐺 ∪ 𝐻))) ⇒ ⊢ (𝜑 → (𝐸[:]𝐼) ≤ (𝐽[:]𝐾)) | ||
| Theorem | fldextrspundglemul 34100 | Given two field extensions 𝐼 / 𝐾 and 𝐽 / 𝐾 of the same field 𝐾, 𝐽 / 𝐾 being finite, and the composiste field 𝐸 = 𝐼𝐽, the degree of the extension of the composite field 𝐸 / 𝐾 is at most the product of the field extension degrees of 𝐼 / 𝐾 and 𝐽 / 𝐾. (Contributed by Thierry Arnoux, 19-Oct-2025.) |
| ⊢ 𝐾 = (𝐿 ↾s 𝐹) & ⊢ 𝐼 = (𝐿 ↾s 𝐺) & ⊢ 𝐽 = (𝐿 ↾s 𝐻) & ⊢ (𝜑 → 𝐿 ∈ Field) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐼)) & ⊢ (𝜑 → 𝐹 ∈ (SubDRing‘𝐽)) & ⊢ (𝜑 → 𝐺 ∈ (SubDRing‘𝐿)) & ⊢ (𝜑 → 𝐻 ∈ (SubDRing‘𝐿)) & ⊢ (𝜑 → (𝐽[:]𝐾) ∈ ℕ0) & ⊢ 𝐸 = (𝐿 ↾s (𝐿 fldGen (𝐺 ∪ 𝐻))) ⇒ ⊢ (𝜑 → (𝐸[:]𝐾) ≤ ((𝐼[:]𝐾) ·e (𝐽[:]𝐾))) | ||
| < Previous Next > |
| Copyright terms: Public domain | < Previous Next > |