Alphabeta Math
TheoremStatement: Literature-sourcedProof: Literature-sourcedPipeline-generatedaudited 2026-09-22
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.

The exact equiconsistency of ZFC and the all-Baire-property model

Statement

The following theories are equiconsistent: ZFC; ZFC plus "every real set first-order definable from a real and an ordinal parameter has the Baire property"; and ZF+DC plus "every set of reals has the Baire property". In particular, Con(ZFC) is equivalent to Con(ZF+DC+all real sets have BP), with no inaccessible-cardinal hypothesis.

Facts & Assumptions

Given: Fixed arithmetizations of the three theories and of ZFC as in the formal-consistency items.

[F1]

Formal consistency of ZFC plus GCH relative to ZF: a verified proof transformation gives Con(ZF)Con(ZFC+GCH), without a transitive model assumption.

[F2]

Shelah's CH-length homogeneous sweet construction: under ZFC+CH there is a CH-length sweet construction whose final algebra is ccc and has the stated homogeneity, free-amalgamation and UM-quotient properties. This interface supplies that mathematical construction, not a uniform formal forcing verification.

[F3]

Shelah's numbered conclusion cited in the source block states exactly that ZFC, ZFC plus the real-and-ordinal-definable Baire-property assertion, and ZF+DC plus universal Baire property are equiconsistent. Its proof remark supplies both forward models: Theorem 7.16 gives the definable-set Baire property in the full forcing extension, while HOD(S) gives the ZF+DC model with universal Baire property. It invokes Gödel's L for the reverse implications. This item uses that published equiconsistency theorem directly; it does not infer a proof-code compiler from [F2].

[F4]

The Shelah inner model satisfies ZF and Dependent Choice with Every real set in the Shelah inner model has the Baire property: inside the extension, N satisfies ZF+DC and every set of reals in N has the Baire property. This interface supplies only the inner model; it is not used to transfer Baire-property witnesses or arbitrary definable sets upward to the full extension.

[F5]

Semantic and formal inner-model theorem for L with The constructible universe satisfies AC: for every model of any of the three theories, its constructible universe satisfies ZFC internally.

Proof

1.1

The exact three-way equiconsistency assertion is Shelah's cited conclusion by [F3]. We record how its two directions match the semantic interfaces developed on this page.

F3
1.2

For the forward construction, the standard L reduction and [F1] provide the CH ground assumed by [F2]. The source theorem and proof remark incorporated in [F3] give the real-and-ordinal-definable Baire-property clause in the full forcing extension. Separately, [F4] gives the inner model NZF+DC+ universal Baire property. These are the two models named in [F3]; no inference from the inner model's witnesses to the full extension is made.

F1F2F3F4
1.3

For the reverse direction, [F3] invokes Gödel's work on L; [F5] is the library's semantic counterpart: the constructible universe internally satisfies ZFC, and the Baire-property clause plays no role.

F3F5
1.4

No inaccessible cardinal is used: the forward route of [F3] is the ccc sweet construction over CH, and the reverse route is L.

F1F2F3
2.1

Thus the published equiconsistency theorem [F3], with steps 1.2--1.3 identifying its constructions with the exact semantic results proved on this page, gives the Statement. Nothing here claims that [F2] alone supplies the uniform proof-code verification required by a formal forcing compiler.

F3step 1.2step 1.3step 1.4

Depends on

Used by

Dependency tree · two levels

38 results within two dependency steps of this one, each drawn at its shortest distance from it. An arrow runs from a result to what uses it, so the chart reads left to right and ends at this result, which carries a heavier outline. Every node is a link to that result. Click elsewhere on the chart to enlarge it.

Sources