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.
Choice and convention ledger for paracompactness, Stone's theorem, and partitions of unity
Paracompactness here means the open-cover refinement property alone; Hausdorffness is not hidden in the word. It is therefore stated in the regularity, normality, shrinking, and partition-of-unity results that use it. The proofs of Every paracompact Hausdorff space is normal and its regularity predecessor use families of all eligible neighbourhoods, so they make no simultaneous choice. The cover-shrinking construction is recorded under the Axiom of Choice, and the partition theorem records Choice and Dependent Choice separately: Choice handles cover assignments, while the cited Urysohn construction is carried out under Dependent Choice.
The accessible primary text of Ornstein's proof has two distinct parts. Part (A) well orders the cover, removes closures of selected dyadic balls, and obtains a point-finite refinement. Part (B) renames that point-finite cover, assigns controlled-radius balls to their first containing member, and upgrades it to a locally finite refinement. Its local-finiteness test uses point-finiteness of the Part (A) output, so the locally finite lemma depends on the point-finite lemma. Stone's theorem is proved here under Choice as a sufficient assumption only; no exact-strength claim is made.
Depends on
- Paracompactness: every open cover has a locally finite open refinement, with no separation axiom built into the word
- Every paracompact Hausdorff space is normal
- Under choice and dependent choice, every open cover of a paracompact Hausdorff space admits a locally finite subordinate partition of unity
- Under choice, every open cover of a metric space has a point-finite open refinement
- Under choice, Ornstein's second construction turns a point-finite metric open cover into a locally finite open refinement
- Stone's theorem, under choice: every metric space is paracompact
Used by
Nothing in the library uses this result yet.
Dependency tree · next 3 levels
Direct dependencies and their dependencies through the next three levels: 81 results over 14 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
- D. Ornstein, A New Proof of the Paracompactness of Metric Spaces, Proc. Amer. Math. Soc. 21 (1969), 341–342 (standard reference, not scraped)
- C. Good, I. J. Tree and W. S. Watson, On Stone's theorem and the axiom of choice (standard reference, not scraped)