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.
Boundedness does not replace pointwise relative compactness for an arbitrary metric target
Statement refuted
The pointwise-relative-compactness hypothesis in Ascoli–Arzelà cannot be weakened to pointwise boundedness for an arbitrary metric target.
Facts & Assumptions
Given: The one-point discrete space and the infinite set with for and otherwise.
The general Ascoli theorem requires pointwise relative compactness, not merely pointwise boundedness (General Ascoli theorem for locally compact Hausdorff domains and metric targets).
In a discrete topology every singleton is open (The discrete, indiscrete, cofinite, cocountable, particular-point and Sierpinski topologies).
A metric on a set is a function such that for all : (M1) if and only if ; (M2) ; (M3) (Metric space: iff , symmetry, and the triangle inequality; pseudometric and ultrametric).
Compact-open subbasic sets are (The compact-open topology on for arbitrary topological spaces).
Counterexample
The function satisfies the three axioms of [L3]: (M1) holds because was defined to mean ; (M2) holds because the defining cases are symmetric in ; and for (M3), if the inequality is trivial, while if then , so differs from at least one of and the right side is at least . So is a metric. Its metric topology is discrete because .
Every map is constant. The whole family is equicontinuous, and is bounded because it lies in the radius- ball about .
Evaluation at is a bijection . By [L4], the inverse image of each open is , so evaluation is a homeomorphism for the compact-open topology.
The open cover of the infinite discrete space has no finite subcover. Thus and hence are not compact, while the family is equicontinuous and pointwise bounded. Moreover is not compact, displaying exactly the missing hypothesis in [L1].
Depends on
- General Ascoli theorem for locally compact Hausdorff domains and metric targets
- The discrete, indiscrete, cofinite, cocountable, particular-point and Sierpinski topologies
- Metric space: $d(x,y) = 0$ iff $x = y$, symmetry, and the triangle inequality; pseudometric and ultrametric
- The compact-open topology on $C(X,Y)$ for arbitrary topological spaces
Used by
Nothing in the library uses this result yet.
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