Existing in Mathlib · Linear algebra
Cayley–Hamilton Theorem
Take a linear transformation of a finite free module, form its characteristic polynomial, and substitute the transformation itself into that polynomial. The resulting endomorphism is zero.
- endomorphism
- characteristic polynomial
- polynomial evaluation
- finite free module
Exact theorem
Exact Mathlib statement
theorem LinearMap.aeval_self_charpoly {R : Type*} {M : Type*} [CommRing R] [AddCommGroup M] [Module R M] [Module.Free R M] [Module.Finite R M] (f : M →ₗ[R] M) : (Polynomial.aeval f) f.charpoly = 0The theorem at a glance
Cayley–Hamilton theorem at a glance
A visual guide to the theorem's hypotheses, structure, and conclusion; the exact statement gives the formal detail.
Cayley–Hamilton theorem at a glance

Detailed visual description
The poster distinguishes an endomorphism from the zero polynomial evaluation, shows the matrix-mediated transformation route without field-only language, and states the commutative-ring finite-free-module scope.
Statement structure
Statement and scope
Read the exact Mathlib declaration
This map summarizes the statement's structure; the exact Mathlib declaration remains authoritative.
Evaluate the characteristic polynomial at its endomorphism

Detailed visual description
The lattice M with loop arrow f leads to a blue box χ_f(T), a substitution arrow T ↦ f, and a green box χ_f(f) = 0_End(M). Below, vectors v₁, v₂, …, vₖ pass through the same polynomial-evaluation box and reach zero. This illustrates an endomorphism of a finite free module over a commutative ring. The zero belongs to the whole polynomial evaluation, not to f.
Why it matters
A mathematical landmark
Cayley–Hamilton binds the polynomial invariants of a linear transformation back to the transformation itself. It is a cornerstone of matrix theory and module-theoretic linear algebra.
ProofAtlas record
What has been checked
Mathlib is the source of the theorem; the local Lean replay and page review are separate.
Claim boundary
No new theorem is claimed
This target indexes Mathlib's theorem that a linear endomorphism of a finite free module over a commutative ring annihilates its own characteristic polynomial. It is not restricted to matrices over a field and does not claim a new proof.
- Proof Atlas did not originate the Cayley–Hamilton theorem or Mathlib's declaration.
- The conclusion says that the characteristic polynomial evaluated at f is zero; it does not say that f itself is zero.
- The generated explanation and visuals are not proof evidence.
Source and local evidence
Where the theorem comes from
- Existing declaration
LinearMap.aeval_self_charpolyin mathlib- Relationship
- The checked artifact is the upstream declaration itself
- Local Lean evidence
artifact.library.mathlib.cayley-hamilton-theorem.v001