Alphabeta Math

Stone–Weierstrass in General

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✓ 13 results · all verified · 10 also independently AI-judged
Every result on this page is machine-checked by a proof checker and read in full and owner-audited; the judge is an additional, independent cross-model AI review of the proofs. The 3 not AI-judged were verified by owner audit (typically over a confirmed judge false positive), not failures.
1 · Prerequisites
Abstract Algebra
Combinatorics
Linear Algebra
Real Analysis
Set Theory
Topology
2 · Logical flowchart

3 · Items

Definition

The two-point duplication property of a function family relative to a target function

Definition

Unital point-separating real vector sublattices of C(X,ℝ)

Definition

Unital, point-separating, and nowhere-vanishing real function algebras on a compact Hausdorff space

Definition

Self-adjoint complex function algebras, unitality, and point separation

Proposition

The general real function-algebra definition agrees with the published compact-metric definition

Lemma

A unital separating real function lattice interpolates arbitrary values at two distinct points

Lemma

A function lattice with the two-point duplication property uniformly approximates its target

Theorem

Lattice Stone–Weierstrass theorem on a compact Hausdorff space

Lemma

The uniform closure of a real function algebra is a vector lattice

Theorem

Real Stone–Weierstrass theorem for compact Hausdorff spaces

Lemma

A nowhere-vanishing real function algebra on a compact space approximates the constant one

Theorem

A separating real function algebra is dense or its closure consists exactly of the functions vanishing at one point

Corollary

A point-separating nowhere-vanishing real function algebra is uniformly dense

Lemma

The real-valued part of a point-separating self-adjoint complex function algebra is separating and has the same common zeros

Theorem

Complex Stone–Weierstrass dichotomy for separating self-adjoint algebras; the unital case is dense

Corollary

The unital algebra generated by a separating complex family and its conjugates is dense

Definition

The quotient that identifies points indistinguishable by a real function algebra

Theorem

A closed unital real function algebra is C(Y,ℝ) on its indistinguishability quotient

Sources