ExampleConstruction: Literature-sourcedVerification: AI-generatedprecheck passjudge pass (gpt-5.6-terra)audited 2026-09-05‡ rests on unproved material (inherited)

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.

‡ Rests on 3 statements not proved in this library, by way of the results it cites. This item cites no such statement directly; it depends on results that do. The unproved premises it inherits are ‡ Cohen's first model: an infinite Dedekind-finite set of reals, ‡ Sierpiński 1947: the generalised continuum hypothesis implies the Axiom of Choice and ‡ The continuum hypothesis and its generalisation are independent of ZFC. Each is recorded with a citation to the literature and is not established here, because the track that would prove it has not yet been developed in this library. Everything else in this proof is proved here.

The underlying category of a Cat-enriched category forgets the 2-cells

Example

Let $K$ be a strict 2-category with a set of objects and small hom-categories, viewed as a $C a t$ -enriched category. Then its underlying ordinary category has the same objects and the same 1-morphisms, but no nonidentity 2-cells.

Facts & Assumptions

Given: A strict 2-category $K$ with a set of objects and small hom-categories.

[L1]

Strict 2-categories and $C a t$ -enriched categories are the same data in the present size range (A Cat-enriched category is exactly a strict 2-category with a set of objects and small hom-categories).

[L2]

The underlying ordinary category of a Cat-enriched category keeps only the objects of each hom-category (The underlying category can lose genuinely enriched information).

Verification

technique · direct

1.1

Read $K$ as a $C a t$ -enriched category using [L1].

L1given

2.1

Then [L2] says that the hom-set in the underlying category is the set of objects of the corresponding hom-category of $K$ . Those objects are the 1-morphisms, while the 2-morphisms are morphisms inside the hom-category and are forgotten.

L2step 1.1∎

Depends on

Used by

Nothing in the library uses this result yet.

Dependency tree · two levels

6 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

Emily Riehl, Categorical Homotopy Theory, Sections 3.1 and 3.4 (standard reference, not scraped)