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.
Assuming Countable Choice, -convergent sequences have almost-everywhere convergent subsequences
Statement
Assume Countable Choice. Let . If in , then some subsequence of admits measurable representatives converging almost everywhere to a measurable representative of .
Facts & Assumptions
Given: Countable Choice (The Axiom of Countable Choice ()) and a norm-convergent sequence in .
Under Countable Choice, Riesz-Fischer completeness states that every norm-convergent sequence in has an almost-everywhere convergent subsequence of representatives (Riesz-Fischer completeness of for ). Applying that representative-selection clause in step 1.1 is the use of Countable Choice here.
Proof
The sequence is Cauchy because it converges in norm. Applying [L1] to that Cauchy sequence gives an limit together with an almost-everywhere convergent subsequence of representatives. Because metric limits are unique, the limit supplied by [L1] must be the given .
That subsequence is the required one.