Alphabeta Math
LemmaStatement: Literature-sourcedProof: AI-generatedprecheck passjudge pass (gpt-5.6-terra)audited 2026-09-05
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.

Measurable coordinatewise functions preserve independence

Statement

Let (Xi)i∈I be an independent family of random elements Xi:(Ω,F,P)→(Si,Σi). For each i, let gi:(Si,Σi)→(Ti,Ti) be measurable. Then the family (gi∘Xi)i∈I is independent.

Facts & Assumptions

Given: Independent random elements Xi and measurable maps gi as in the Statement.

[L1]

Measurable outer maps preserve measurability under composition. (Composition with a Borel measurable outer map preserves measurability)

[L2]

Independence of random elements is equivalent to the rectangle criterion. (Independent random elements are characterized by finite rectangle probabilities)

Proof

technique · direct
1.1givenL1

By [L1], each composite gi∘Xi is again a random element.

1.2givenL2

Fix a finite list of distinct indices i0,…,in−1 and measurable sets Ck∈Tik. Then gik−1(Ck)∈Σik for every k, so [L2] applied to the independent family (Xi) gives P(gi0(Xi0)∈C0,…,gin−1(Xin−1)∈Cn−1)=∏k<nP(gik(Xik)∈Ck).

2.1step 1.1step 1.2L2∎

Step 1.2 is exactly the rectangle criterion for the family (gi∘Xi)i∈I, so [L2] shows that this family is independent.

Depends on

Used by

…and 29 more results.

Dependency tree · two levels

9 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