Shape: mathematical research article

The shape of a proof-centred mathematics article on the AMS amsart class: the field's Introduction-Results genre, the main theorem stated in section 1, milestones before details, and each proof naming what it uses.

When to use it

  • A research article whose contribution is theorems and their proofs, for a journal or arXiv.
  • A thesis chapter with the same contribution; keep the institution's class for layout and take the section order from here.
  • Not for an empirical study: the research paper shape covers IMRaD.
  • Not for a survey or a monograph, whose order follows the subject rather than one main theorem.
  • Not literally for papers that fill a journal issue; Krantz 2017 says the scheme bends there.

How each part maps to the evidence

Part What it does Evidence Grade
Class and theorem styles amsart; plain, definition and remark styles from amsthm AMS 2017, amscls, amsthm convention, enforced by the publisher
Abstract before \maketitle short, no citations; under 1920 characters for arXiv AMS 2017, arXiv 2026 convention, enforced
MSC 2020 code, keywords at least one primary code; keywords optional AMS 2017, MSC2020 convention, enforced
Introduction, plain first paragraph the result in words before any definition Krantz 2017 convention, untested
Main results in section 1 self-contained one-sentence theorem, stated before its proof Kuteeva 2015 (21 of 22 openings), Halmos 1970, Tao 2026a measured, descriptive; convention for the effect
Relation to previous work what is new, and an example showing a hypothesis is needed Tao 2026a convention, untested
Idea of the proof the milestones and how they combine Krantz 2017, Tao 2026b convention, untested
Organisation paragraph one sentence per section Krantz 2017 convention, untested
Preliminaries and notation notation fixed once so statements stand alone Kuteeva 2015 (17 of 22 have such a section), Knuth 1989 measured, descriptive
Results before proofs milestones stated, then the main theorem derived from them Krantz 2017, Tao 2026b convention, untested
Uses line in each proof the results a proof depends on, so the dependency tree is explicit Massot 2026, Tao 2026b, Tao 2023 convention, untested for human readers
Proofs: sketch, then numbered steps holistic summary first, then explicit warrants Fuller 2014, Inglis 2012, Lamport 2012 measured, one study; see proof
Ending optional remarks or open questions; the field has no fixed ending Kuteeva 2015 (11 of 22 have no conclusion) measured, descriptive

Each key (Author Year) is listed in references. No part of this shape has been tested against the conventional article on reader outcomes; baseline says how it would be.

The principles it applies

Part Principle
Main theorem stated in section 1, in words before any definition overview first
Idea of the proof before its details overview first
Notation fixed once, in Preliminaries define before use, one place per fact
A Uses line in each proof; results ordered so each comes after what it uses short reference distance
Sections on at most three levels shallow outline

Skeleton

Copy this into a new file, or start from the LaTeX version, mathematical-article.tex.

# A title that names the result

Author Name, Department, Institution, City, Country.

**Abstract.** One to three sentences: what is proved, under which hypotheses, and why it matters. No citations; the AMS proceedings checklist suggests at most about 150 words for a short paper and 300 for a long one, and arXiv accepts under 1920 characters.

**MSC 2020.** Primary 00-XX; Secondary 00-XX (replace by full codes from msc2020.org).

**Keywords.** first keyword, second keyword.

## 1. Introduction

State the main result in one or two plain sentences that a reader outside the subfield can follow.

### 1.1 Main results

**Theorem 1.1.** Let $X$ be an object of the kind studied here. If $X$ satisfies condition $(\ast)$, then $X$ has property $P$.

**Corollary 1.2.** A consequence of Theorem 1.1 that a reader in a neighbouring field would use.

If Theorem 1.1 is too technical for the introduction, state an informal version labelled "informal" and point to the precise statement.

### 1.2 Relation to previous work

Say what was known, one sentence per result, with citations [1].
Say what this paper adds.
Give an example showing that condition $(\ast)$ cannot be removed.

### 1.3 Idea of the proof

The proof has three steps.
Proposition 3.1 reduces Theorem 1.1 to a statement about a simpler object.
Lemma 3.2 proves that statement in a special case, and Lemma 3.3 extends it.
The new difficulty sits in Lemma 3.3.

### 1.4 Organisation

Section 2 fixes notation and recalls known results.
Section 3 states the milestones and derives Theorem 1.1 from them.
Section 4 proves the milestones.

## 2. Preliminaries and notation

Throughout, $X$ denotes an object of the kind studied here and $n \geq 1$ an integer.

**Definition 2.1.** An object $X$ satisfies *condition $(\ast)$* if it has the defining property.

**Theorem 2.2 (known, [2]).** Quote the known theorem exactly as it is used, with its source.

## 3. Results

**Proposition 3.1.** If Lemmas 3.2 and 3.3 hold, then every $X$ satisfying $(\ast)$ has property $P$.

**Lemma 3.2.** The special case of property $P$ holds.

**Lemma 3.3.** If the special case holds, then the general case holds.

*Proof of Theorem 1.1.*
Uses: Proposition 3.1, Lemmas 3.2 and 3.3.
Lemma 3.2 gives the special case, Lemma 3.3 extends it, and Proposition 3.1 concludes. $\square$

## 4. Proofs

*Proof of Proposition 3.1.*
Uses: Definition 2.1, Theorem 2.2.
A short argument stays a paragraph: say what is shown, then why, naming each result where it is used. $\square$

*Proof of Lemma 3.2.*
Uses: Definition 2.1, Theorem 2.2.

Sketch: one sentence that gives the idea, so a reader can stop here.

- ⟨1⟩1. First claim. *Proof:* by Definition 2.1.
- ⟨1⟩2. Second claim. *Proof:* by ⟨1⟩1 and Theorem 2.2.
- ⟨1⟩3. Q.E.D. *Proof:* by ⟨1⟩1 and ⟨1⟩2. $\square$

*Proof of Lemma 3.3.*
Uses: Lemma 3.2.

Sketch: one sentence that names the new difficulty and how it is overcome.

- ⟨1⟩1. Reduction to the special case. *Proof:* by Lemma 3.2.
- ⟨1⟩2. Q.E.D. *Proof:* by ⟨1⟩1. $\square$

The full proof shape, with deeper levels and when to keep a paragraph, is in [proof.md](proof.md).

## Acknowledgements

Funding and thanks.

## References

1. A. Author, *Title of the earlier result*, Journal **1** (2000), 1-10.
2. B. Author, *Title of the known theorem*, Publisher, City, 2010.

Worked example

A classical theorem written to this shape, with its proof in the structured form of proof.md.

# Every finite tournament has a Hamiltonian path

A worked example for this shape.

**Abstract.** Every tournament on $n \geq 1$ vertices has a directed path through all its vertices. The proof inserts
one vertex at a time.

**MSC 2020.** Primary 05C20; Secondary 05C38.

**Keywords.** tournament, Hamiltonian path, induction.

## 1. Introduction

In any round-robin contest with no draws, the players can be listed so that each one beat the next.

### 1.1 Main results

**Theorem 1.1.** Every tournament on $n \geq 1$ vertices has a Hamiltonian path.

### 1.2 Relation to previous work

Rédei proved this, and that the number of such paths is odd [1]; this note proves existence only. Completeness
cannot be dropped: on vertices $a, b, c$ with arcs $a \to b$ and $c \to b$ only, no path passes through all three.

### 1.3 Idea of the proof

Lemma 3.1 inserts a new vertex into any directed path; induction on $n$ then builds the whole path.

### 1.4 Organisation

Section 2 defines the terms, Section 3 states the lemma and derives the theorem, and Section 4 proves the lemma.

## 2. Preliminaries and notation

**Definition 2.1.** A *tournament* is a finite set $V$ of vertices with, for each pair of distinct vertices $u, v$,
exactly one of the arcs $u \to v$ and $v \to u$.

**Definition 2.2.** A *Hamiltonian path* is a list $v_1, \dots, v_n$ of all the vertices, each once, with
$v_i \to v_{i+1}$ for every $i < n$.

## 3. Results

**Lemma 3.1.** Let $v_1, \dots, v_k$ be a directed path in a tournament and $u$ a vertex not on it. Then $u$ can be
inserted into the path so that $v_1, \dots, v_k$ and $u$ form a directed path.

*Proof of Theorem 1.1.*
Uses: Lemma 3.1.
By induction on $n$: one vertex is a path. For $n \geq 2$, remove a vertex $u$; the rest is a tournament with a
Hamiltonian path, and Lemma 3.1 inserts $u$. $\square$

## 4. Proofs

*Proof of Lemma 3.1.*
Uses: Definition 2.1.

Sketch: put $u$ just before the first vertex it beats.

- ⟨1⟩1. If $u \to v_1$, then $u, v_1, \dots, v_k$ is a path.
- ⟨1⟩2. If $v_k \to u$, then $v_1, \dots, v_k, u$ is a path.
- ⟨1⟩3. Otherwise $v_1 \to u$ and $u \to v_k$. Let $j$ be the least index with $u \to v_j$; then $j \geq 2$,
  and $v_{j-1} \to u$, so $v_1, \dots, v_{j-1}, u, v_j, \dots, v_k$ is a path.
  *Proof:* $j$ exists since $u \to v_k$, and $j \neq 1$ since $v_1 \to u$; by the choice of $j$, $u \to v_{j-1}$
  fails, so $v_{j-1} \to u$ by Definition 2.1.
- ⟨1⟩4. Q.E.D. *Proof:* by Definition 2.1 either $u \to v_1$ or $v_1 \to u$, and either $v_k \to u$ or
  $u \to v_k$, so ⟨1⟩1 to ⟨1⟩3 cover every case. $\square$

## References

1. L. Rédei, *Ein kombinatorischer Satz*, Acta Litterarum ac Scientiarum Szeged **7** (1934), 39-43.