Public Mathlib landmark · existing upstream theorem · read-only

Algebra · existing Mathlib declaration

Primitive Element Theorem

If E is a finite-dimensional separable extension of a field F, then one can choose an element α of E such that adjoining α to F produces all of E. The generator exists, but the theorem does not say that it is unique or canonical.

The theorem at a glance

Primitive element theorem at a glance

A source-bound editorial overview of the exact Mathlib formulation. The image is explanatory; the statement map, formal type, and pinned source remain authoritative.

A finite-dimensional separable field extension is simple: one element generates the whole extension over the base field. Generated explanation only; the exact HTML statement and pinned source are authoritative.
Detailed visual description

The poster states the finite-dimensional separable hypotheses, contrasts the cyclic-generator route for finite base fields with simple-adjoin compression over infinite base fields, brings both routes to one gold generator, and closes with the theorem's exact non-uniqueness and non-cardinality boundary.

Formal orientation

Statement map

Statement map for Primitive Element TheoremEvery finite-dimensional separable field extension is generated over its base field by a single element. The pinned upstream declaration is Field.exists_primitive_element. The exact checked statement is theorem Field.exists_primitive_element (F E : Type*) [Field F] [Field E] [Algebra F E] [FiniteDimensional F E] [Algebra.IsSeparable F E] : ∃ α : E, F⟮α⟯ = ⊤.Mathematical readingEvery finite-dimensionalseparable fieldextension is generatedover its base field by asingle element.Pinned declarationmathlib ·Field.exists_primitive_elementExact checked formtheoremField.exists_primitive_element(F E : Type*) [Field F][Field E] [Algebra F E][FiniteDimensional F E][Algebra.IsSeparable FE] : ∃ α : E, F⟮α⟯ = ⊤Statement map for Primitive Element TheoremEvery finite-dimensional separable field extension is generated over its base field by a single element. The pinned upstream declaration is Field.exists_primitive_element. The exact checked statement is theorem Field.exists_primitive_element (F E : Type*) [Field F] [Field E] [Algebra F E] [FiniteDimensional F E] [Algebra.IsSeparable F E] : ∃ α : E, F⟮α⟯ = ⊤.Mathematical readingEvery finite-dimensionalseparable fieldextension is generatedover its base field by asingle element.Pinned declarationmathlib ·Field.exists_primitive_elementExact checked formtheoremField.exists_primitive_element(F E : Type*) [Field F][Field E] [Algebra F E][FiniteDimensional F E][Algebra.IsSeparable FE] : ∃ α : E, F⟮α⟯ = ⊤

This deterministic map orients the reader from the mathematical summary to the pinned declaration and exact checked form. The HTML statement below is authoritative.

A finite-dimensional separable extension is generated by one element. Scientific diagram · explanatory, not proof evidence.
Detailed visual description

This target indexes Mathlib's existence theorem for a primitive element of a finite-dimensional separable field extension E/F: some α : E satisfies F⟮α⟯ = ⊤. Finite means finite-dimensional, not finite cardinality. The result does not assert uniqueness or canonicity of α and does not cover general inseparable extensions.

Complementary intuition

A mathematical landmark

The primitive element theorem compresses a finite-dimensional separable extension from many possible generators to one. It is a foundational bridge between abstract field extensions and the concrete study of a single minimal polynomial.

The low-text schematic gives the theorem a visual identity; it does not replace the source-bound poster or exact statement.

Authoritative formal type

Exact Mathlib statement

theorem Field.exists_primitive_element (F E : Type*) [Field F] [Field E] [Algebra F E] [FiniteDimensional F E] [Algebra.IsSeparable F E] : ∃ α : E, F⟮α⟯ = ⊤
Selected evidence declaration text
theorem Field.exists_primitive_element (F E : Type*) [Field F] [Field E] [Algebra F E] [FiniteDimensional F E] [Algebra.IsSeparable F E] : ∃ α : E, F⟮α⟯ = ⊤

ProofAtlas record

What has been checked

Upstream indexedPinned source bytes verified locally
Locally reproducedExact upstream declaration replayed
Reviewed pageCurrent public presentation reviewed
Accepted Atlas resultNot recorded for the preferred artifact

These states distinguish upstream identity, local reproduction, review, and Atlas acceptance. This page is part of the public, read-only Mathlib landmark collection.

Claim boundary

No new theorem is claimed

This target indexes Mathlib's existence theorem for a primitive element of a finite-dimensional separable field extension E/F: some α : E satisfies F⟮α⟯ = ⊤. Finite means finite-dimensional, not finite cardinality. The result does not assert uniqueness or canonicity of α and does not cover general inseparable extensions.

Provenance

Origin and evidence stay separate

Existing declaration
Field.exists_primitive_element in mathlib
Relationship
The checked artifact is the upstream declaration itself
Preferred checked artifact
artifact.library.mathlib.primitive-element-theorem.v001
Source handling
Verified upstream reference; no mirrored source package