Lean verification record

Checked Artifact: Fermat's Last Theorem for Exponent Four (mathlib)

Proof Atlas collected build, no-sorry, axiom, and clean-source evidence directly from the pinned upstream declaration.

Verification result

The recorded Lean checks passed

Build replaypassed with retained transcript
Unfinished stepsNone found
Source identityPinned commit and file recorded
Dependency profileAxiom closure recorded

Reproducibility details

What the checker recorded

Declaration checked: fermatLastTheoremFour
Module: Mathlib.NumberTheory.FLT.Four
Source file checked: Mathlib/NumberTheory/FLT/Four.lean
Package commit: 5e932f97dd25535344f80f9dd8da3aab83df0fe6
Build transcript: passed · retained with this record
Unfinished proof steps: None found by the recorded no-sorry scan
Axiom closure: Classical.choice, Quot.sound, propext
Collection provenance: Clean source state recorded

ProofAtlas record

What has been checked

Upstream indexedPinned source bytes verified locally

Locally reproducedExact upstream declaration replayed

Reviewed pageCurrent public presentation reviewed

Accepted Atlas resultNot recorded for the preferred artifact

Mathlib is the source of the theorem; the local Lean replay and page review are separate.

Evidence boundary

Exact formal statement only

This target indexes Mathlib's theorem FermatLastTheoremFor 4. Unfolded, for natural numbers a, b, and c, if all three are nonzero then a ^ 4 + b ^ 4 ≠ c ^ 4. The source proves this through a stronger integer square equation and infinite descent. The declaration is the exponent-four case only, not full Fermat's Last Theorem, an exponent-general theorem, or new ProofAtlas mathematics.

This checker record does not establish novelty, transfer a historical acceptance decision, or authorize publication.