Technical Lean evidence 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.
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
fermatLastTheoremFour- Module
Mathlib.NumberTheory.FLT.Four- Source file checked
Mathlib/NumberTheory/FLT/Four.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 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 is evidence for the exact formal statement only. It does not establish novelty, transfer a historical acceptance decision, or authorize publication.