Technical Lean evidence record
Checked Artifact: Kruskal–Katona Theorem (mathlib)
Proof Atlas collected build, no-sorry, axiom, and clean-source evidence directly from the pinned upstream declaration.
ProofAtlas record
What has been checked
These states distinguish upstream identity, local reproduction, review, and Atlas acceptance. This page is part of the public, read-only Mathlib landmark collection.
Mechanical evidence
- Declaration checked
Finset.kruskal_katona- Module
Mathlib.Combinatorics.SetFamily.KruskalKatona- Source file checked
Mathlib/Combinatorics/SetFamily/KruskalKatona.lean- Package commit
5e932f97dd25535344f80f9dd8da3aab83df0fe6- Build
- passed · transcript retained
- Unfinished proof steps
- None found by the recorded no-sorry scan
- Axiom closure
- Classical.choice, Quot.sound, propext
- Clean collection provenance
- Recorded
Evidence boundary
This page indexes Mathlib’s colex-initial-segment form of the Kruskal–Katona theorem for finite families of subsets of Fin n. The comparison family 𝒜 is r-uniform, 𝒞 is a colex initial segment of the r-subsets, and #𝒞 may be smaller than #𝒜. The selected endpoint compares only the cardinalities of their immediate one-element-deletion shadows. It is not the later iterated-shadow theorem, the Lovász/binomial formulation, an equality-case classification, a uniqueness theorem, or an algorithm.
This checker record is evidence for the exact formal statement only. It does not establish novelty, transfer a historical acceptance decision, or authorize publication.