Public Mathlib landmark · existing upstream theorem · read-only

Combinatorics · existing Mathlib declaration

Roth’s Theorem

Among the first N natural numbers, a set that avoids every nontrivial three-term arithmetic progression must occupy a proportion that tends to zero as N grows.

The theorem at a glance

Roth’s Theorem at a glance

A source-bound editorial overview of the exact Mathlib formulation. The image is explanatory; the statement map, formal type, and pinned source remain authoritative.

The largest three-term-progression-free subset of {0,…,N−1} has density tending to zero, with no explicit rate claimed by the selected declaration. Generated explanation only; the exact HTML statement and pinned source are authoritative.
Detailed visual description

The poster defines rothNumberNat, places the qualitative little-o conclusion at the top, and follows the retained source architecture from a dense subset through a grid corner and triangle-removal/regularity motif to three exactly equally spaced points. The exact-scope footer rules out an explicit rate.

Formal orientation

Statement map

Statement map for Roth’s TheoremThe maximum size of a three-term-arithmetic-progression-free subset of {0,…,N−1} is little-o of N. The pinned upstream declaration is rothNumberNat_isLittleO_id. The exact checked statement is theorem rothNumberNat_isLittleO_id : IsLittleO atTop (fun N ↦ (rothNumberNat N : ℝ)) (fun N ↦ (N : ℝ)).Mathematical readingThe maximum size of athree-term-arithmetic-progression-freesubset of {0,…,N−1} islittle-o of N.Pinned declarationmathlib ·rothNumberNat_isLittleO_idExact checked formtheoremrothNumberNat_isLittleO_id: IsLittleO atTop (fun N↦ (rothNumberNat N : ℝ))(fun N ↦ (N : ℝ))Statement map for Roth’s TheoremThe maximum size of a three-term-arithmetic-progression-free subset of {0,…,N−1} is little-o of N. The pinned upstream declaration is rothNumberNat_isLittleO_id. The exact checked statement is theorem rothNumberNat_isLittleO_id : IsLittleO atTop (fun N ↦ (rothNumberNat N : ℝ)) (fun N ↦ (N : ℝ)).Mathematical readingThe maximum size of athree-term-arithmetic-progression-freesubset of {0,…,N−1} islittle-o of N.Pinned declarationmathlib ·rothNumberNat_isLittleO_idExact checked formtheoremrothNumberNat_isLittleO_id: IsLittleO atTop (fun N↦ (rothNumberNat N : ℝ))(fun N ↦ (N : ℝ))

This deterministic map orients the reader from the mathematical summary to the pinned declaration and exact checked form. The HTML statement below is authoritative.

For sufficiently large intervals, a subset of fixed positive density cannot avoid a nontrivial three-term arithmetic progression. Scientific diagram · explanatory, not proof evidence.
Detailed visual description

This page indexes Mathlib’s qualitative asymptotic declaration for the natural-number Roth function. Here rothNumberNat N is the maximum cardinality of a ThreeAPFree subset of Finset.range N = {0,…,N−1}, and ThreeAPFree excludes nontrivial a,b,c in the set with a+c=b+b. The exact conclusion is an IsLittleO atTop relation after coercion to ℝ. It does not state an explicit decay rate, a finite threshold, a modern quantitative bound, or a theorem about longer progressions.

Complementary intuition

A mathematical landmark

Roth’s theorem is a foundational density result in additive combinatorics. Mathlib’s retained route connects one-dimensional three-term progressions to two-dimensional corners, triangle removal, and Szemerédi regularity.

The low-text schematic gives the theorem a visual identity; it does not replace the source-bound poster or exact statement.

Authoritative formal type

Exact Mathlib statement

theorem rothNumberNat_isLittleO_id : IsLittleO atTop (fun N ↦ (rothNumberNat N : ℝ)) (fun N ↦ (N : ℝ))
Selected evidence declaration text
theorem rothNumberNat_isLittleO_id : IsLittleO atTop (fun N ↦ (rothNumberNat N : ℝ)) (fun N ↦ (N : ℝ))

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

These states distinguish upstream identity, local reproduction, review, and Atlas acceptance. This page is part of the public, read-only Mathlib landmark collection.

Claim boundary

No new theorem is claimed

This page indexes Mathlib’s qualitative asymptotic declaration for the natural-number Roth function. Here rothNumberNat N is the maximum cardinality of a ThreeAPFree subset of Finset.range N = {0,…,N−1}, and ThreeAPFree excludes nontrivial a,b,c in the set with a+c=b+b. The exact conclusion is an IsLittleO atTop relation after coercion to ℝ. It does not state an explicit decay rate, a finite threshold, a modern quantitative bound, or a theorem about longer progressions.

Provenance

Origin and evidence stay separate

Existing declaration
rothNumberNat_isLittleO_id in mathlib
Relationship
The checked artifact is the upstream declaration itself
Preferred checked artifact
artifact.library.mathlib.roth-theorem.v001
Source handling
Verified upstream reference; no mirrored source package