Theorem

One block for every kind of mathematical statement: theorem, lemma, proposition, corollary, definition, remark, example and proof. Texifine sets them in the standard styles of the amsthm package and numbers them for you.

Writing a statement

Insert a Theorem block. It opens with one empty line: type the statement there.

• Enter adds a line to the statement.
• Enter on an empty last line leaves the statement and continues below it.
• You can also type / in an empty paragraph and choose Theorem.
• To bring paragraphs, lists or equations you already wrote into a statement, drag them into it.

A statement is made of ordinary blocks. It can hold paragraphs, lists and equations, which you add, move and delete as anywhere else.

Choosing the kind

Click the heading of the block — "Theorem 2.1" — and pick a kind in the menu. The number updates on its own. The same choice is in the right column.

The heading is written in the document's language: "Théorème", "Lemme", "Démonstration" in a French document.

Naming a statement

Type a name in the field after the heading. It is printed in brackets after the number:

Theorem 2.1 (Pythagoras). In a right triangle…

For a proof, the name replaces the heading: type "Proof of Lemma 3" and the PDF prints that instead of "Proof".

Up to 200 characters, plain text.

Numbering

Theorems, lemmas, propositions, corollaries and definitions share one counter: Definition 1, Theorem 2, Lemma 3. A reader looking for "Lemma 3" finds it between 2 and 4.

The counter restarts at each chapter and carries its number: 2.1, 2.2… inside chapter 2. Before the first chapter, or without chapters, statements are numbered 1, 2, 3.

Remarks, examples and proofs are never numbered.

Adding a proof

Hover or select a theorem, lemma, proposition or corollary and click Add a proof under it. A proof block is inserted right after, ready to type in.

A proof is a block of its own: you can move it, write it later, or put a remark between a theorem and its proof.

Referring to a statement

Press Ctrl+Alt+R in any text and choose the statement. The list shows each one under its own kind and number — "Lemma 2.3" — with its name or its first words.

Only numbered kinds can be referenced. If you turn a lemma into a remark, the references to it show "?" until you choose another target.

What it cannot do

• Only paragraphs, lists and equations inside. A figure, a table, a code listing, a quote, a heading or columns dropped on a statement land beside it.
• No statement inside a statement. A proof is placed after its theorem, not in it.
• The styles are fixed. No custom colours, frames or fonts, and no custom kinds (axiom, conjecture, exercise…) yet.
• One shared counter. Numbering each kind separately (Theorem 1, Lemma 1) is not available yet.
• Numbered kinds are always numbered; remarks, examples and proofs never are.
• A proof that ends with an equation prints its □ on the line below the equation.
• A statement that starts with a list prints the first item on the same line as the heading in the PDF. Start with a sentence to avoid it.

A statement can be placed inside a column.

What it prints

\begin{theorem}[{Uniqueness of the identity}]\label{blk-…}
A group has exactly one identity element.
\end{theorem}

\begin{proof}
Let $e$ and $e'$ be two identity elements. Then $e = e \cdot e' = e'$.
\end{proof}

The preamble declares each kind you use, in the document's language:

\usepackage{amsthm}
\theoremstyle{plain}
\newtheorem{theorem}{Theorem}[chapter]
\theoremstyle{definition}
\newtheorem{definition}[theorem]{Definition}