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.
Closed graph theorem
Statement
Assume DC. For Banach spaces and an everywhere-defined linear , is bounded if and only if its graph (The graph of a linear operator with a linear domain) is closed.
Facts & Assumptions
Given: DC, Banach spaces , and an everywhere-defined linear map .
Proof
If is bounded, and , continuity gives , so the graph is closed.
Conversely, a closed graph is Banach by A closed subspace of a Banach space is Banach, since is Banach by Finite products of Banach spaces are Banach.
The first projection is a bounded linear bijection; its inverse is bounded by Bounded inverse theorem. Composing that inverse with the second projection makes bounded.
Depends on
Used by
Nothing in the library uses this result yet.
Dependency tree · two levels
12 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
- Buhler--Salamon, Functional Analysis, Theorem 2.20 (standard reference, not scraped)