Alphabeta Math
DefinitionDefinition: AI-adaptedProof: Not applicableSession-authored (Fable 5 assisted)judge pass (z-ai/glm-5.2)audited 2026-07-31 rests on unproved material (inherited)
How statement and proof provenance work

The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.

  • Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
  • AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
  • AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.

These labels describe origin, not correctness: citations and verification chips remain separate evidence.

Rests on 3 statements not proved in this library, by way of the results it cites. This item cites no such statement directly; it depends on results that do. The unproved premises it inherits are Cohen's first model: an infinite Dedekind-finite set of reals, Sierpiński 1947: the generalised continuum hypothesis implies the Axiom of Choice and The continuum hypothesis and its generalisation are independent of ZFC. Each is recorded with a citation to the literature and is not established here, because the track that would prove it has not yet been developed in this library. Everything else in this proof is proved here.

Under choice, weight w(X)w(X), density d(X)d(X), local character χ(x,X)\chi(x,X), and character χ(X)\chi(X) as raw cardinal minima and a supremum

Definition

Assume the Axiom of Choice (The Axiom of Choice) and let XX be a topological space. The weight w(X)w(X) is the least cardinality of a basis for XX, and the density d(X)d(X) is the least cardinality of a dense subset of XX (Basis and subbasis for a topology, and the topology generated by a family of sets, Dense, nowhere dense and codense subsets of a topological space, and the criterion by basic open sets, Cardinal (initial ordinal) and cardinality).

For xXx\in X, the local character χ(x,X)\chi(x,X) is the least cardinality of a neighbourhood base at xx (Neighbourhood of a point and neighbourhood base, with this library's convention that a neighbourhood need not be open). The character is the raw cardinal supremum χ(X)=sup{χ(x,X):xX}.\chi(X)=\sup\{\chi(x,X):x\in X\}.

No 0\aleph_0 normalization is imposed. In particular a one-member local base has cardinality 11, not 0\aleph_0. The forward lemmas named in justified_by establish the asserted minima and supremum.

Depends on

Used by

Dependency tree · next 3 levels

Direct dependencies and their dependencies through the next three levels: 66 results over 20 levels. An arrow runs from a result to what uses it, and this result sits at the bottom with a heavier outline. Click the chart to enlarge it.

Sources