Alphabeta Math
TheoremStatement: Literature-sourcedProof: AI-generatedSession-authored (Fable 5 assisted)precheck passjudge 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, every metrizable space has w(X)=d(X)w(X)=d(X)

Statement

Assuming choice, every metrizable space satisfies w(X)=d(X)w(X)=d(X) under the raw convention.

Facts & Assumptions

Proof

technique · direct
1.1

Suppose first that κ\kappa is infinite. The family B={B(d,q):dD, qQ, q>0}\mathcal B=\{B(d,q):d\in D,\ q\in\mathbb Q,\ q>0\} has cardinality at most κ0=κ\kappa\cdot\aleph_0=\kappa by [L2] and [L3]. It is a basis: if xUx\in U with UU open, choose ε>0\varepsilon>0 with B(x,ε)UB(x,\varepsilon)\subseteq U, choose dDd\in D with d(x,d)<ε/3d(x,d)<\varepsilon/3, and then by [L2] choose a positive rational qq with d(x,d)<q<εd(x,d)d(x,d)<q<\varepsilon-d(x,d). Thus xB(d,q)B(x,ε)Ux\in B(d,q)\subseteq B(x,\varepsilon)\subseteq U. Hence w(X)κ=d(X)w(X)\le\kappa=d(X).

givenL2L3
1.2

Suppose κ\kappa is finite. If D=D=\varnothing, density forces X=X=\varnothing and both raw invariants are 00. Otherwise X=DX=D: if xDx\notin D, the finitely many positive distances d(x,a)d(x,a) for aDa\in D have a positive minimum, and a smaller ball about xx misses DD, contradicting density. A finite metric space is discrete, since at each point a ball smaller than all distances to the other finitely many points is a singleton. The singleton family is a basis of size X|X|, and every basis of a discrete space must contain each singleton; also every dense set must contain every point. Therefore w(X)=X=d(X)=κw(X)=|X|=d(X)=\kappa.

given
2.1

Step 1.1 handles infinite density and step 1.2 handles finite density; combining the resulting upper bound with [L1] gives w(X)=d(X)w(X)=d(X) in every case.

step 1.1step 1.2L1

Depends on

Used by

Dependency tree · next 3 levels

Direct dependencies and their dependencies through the next three levels: 180 results over 31 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