Existing in Mathlib · Number theory
Fundamental Theorem of Arithmetic
Prime factors are unique apart from their order: if a list contains only primes and multiplies to n, it contains exactly the same prime factors, with the same multiplicities, as n.primeFactorsList.
- prime factorization
- unique factorization
- list permutation
- natural numbers
Exact theorem
Exact Mathlib statement
theorem Nat.primeFactorsList_unique {n : ℕ} {l : List ℕ} (h₁ : l.prod = n) (h₂ : ∀ p ∈ l, Nat.Prime p) : l.Perm n.primeFactorsListThe theorem at a glance
Fundamental Theorem of Arithmetic — exact Mathlib form
A visual guide to the theorem's hypotheses, structure, and conclusion; the exact statement gives the formal detail.
Fundamental Theorem of Arithmetic — exact Mathlib form

Detailed visual description
The retained poster presents the exact hypotheses, permutation conclusion, reading sequence, and boundary of Nat.primeFactorsList_unique without adding a factorization algorithm or ordered-list claim.
Statement structure
From hypotheses to conclusion
This map summarizes the statement's structure; the exact Mathlib declaration remains authoritative.
The same prime factors, in another order

Detailed visual description
The theorem compares any finite all-prime list with the canonical prime-factor list after establishing that both multiply to the same natural number.
Why it matters
A mathematical landmark
Unique prime factorization is the organizing principle behind elementary arithmetic and much of number theory. This declaration isolates its uniqueness half in an exact finite-list form.
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 uniqueness theorem for prime-factor lists: any list of primes with product n is a permutation of n.primeFactorsList. It does not claim an ordered factorization, a factorization algorithm, a new proof, or a new mathematical result.
- This selected declaration does not provide a factorization algorithm.
- It proves uniqueness up to permutation, not equality of arbitrarily ordered lists.
- ProofAtlas is indexing an existing Mathlib theorem, not claiming new mathematics.
Source and local evidence
Where the theorem comes from
- Existing declaration
Nat.primeFactorsList_uniquein mathlib- Relationship
- The checked artifact is the upstream declaration itself
- Local Lean evidence
artifact.library.mathlib.fundamental-theorem-arithmetic.v001