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.
Approximation property and bounded approximation property
Definition
Let be a Banach space. It has the approximation property (AP) if for every norm-compact set and every there is a bounded finite-rank operator such that
Here finite rank means that is finite-dimensional.
For , has the -bounded approximation property (-BAP) if the same assertion holds with the additional operator-norm bound , where the norm is that of The operator norm as the least bound and as the unit-sphere or unit-ball supremum. It has the bounded approximation property (BAP) if it has -BAP for some finite .
No sequence of approximating operators is required; this matters in nonseparable spaces. Plainly -BAP implies AP.
Depends on
Used by
- Enflo finite-expansion and localized-trace system Definition
- Enflo's quantitative localized-trace obstruction Lemma
- Enflo's space without the approximation property Remark
- Subspaces of classical spaces can fail the approximation property Remark
- A Schauder basis implies the bounded approximation property Theorem
- Reflexive approximation property implies metric approximation property Theorem
Dependency tree · two levels
8 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
- Per Enflo, A counterexample to the approximation problem in Banach spaces (standard reference, not scraped)