Proclamations with style
6.4.2 Proclamations with style
You can choose one of three styles for your proclamations by preceding the definitions with the \theoremstyle{style} command, where style is one of the following:
plain, the most emphatic definition remark, the least emphatic
There are a few extra options, including the \newtheorem* command, an unnum- bered version of \newtheorem. The following commands set the styles in the sampart.tex article (see page 290). The typeset sample article (on pages 286–288) shows how the chosen styles affect the typeset proclamations.
\theoremstyle{plain} \newtheorem{theorem}{Theorem} \newtheorem{corollary}{Corollary} \newtheorem*{main}{Main Theorem} \newtheorem{lemma}{Lemma} \newtheorem{proposition}{Proposition}
\theoremstyle{definition} \newtheorem{definition}{Definition}
\theoremstyle{remark} \newtheorem*{notation}{Notation}
A proclamation created by a \newtheorem command has the style of the last \theoremstyle command preceding it. The default style is plain.
Three examples Here are three sets of proclamation definitions to illustrate different styles and number-
ing schemes. Example 1 \theoremstyle{plain}
\newtheorem{theorem}{Theorem} \newtheorem{lemma}[theorem]{Lemma} \newtheorem{definition}[theorem]{Definition} \newtheorem{corollary}[theorem]{Corollary}
130 Chapter 6 Text environments
In a document with this set of proclamation definitions you can use theorems, lemmas, definitions, and corollaries, typeset in the most emphatic (plain) style. They are all numbered consecutively: Definition 1, Definition 2, Theorem 3, Corollary 4, Lemma 5 , Lemma 6, Theorem 7, and so on.
Example 2 \theoremstyle{plain}
\newtheorem{theorem}{Theorem} \newtheorem*{main}{Main Theorem} \newtheorem{definition}{Definition}[section] \newtheorem{lemma}[definition]{Lemma}
\theoremstyle{definition} \newtheorem*{Rule}{Rule}
In this document you may use theorems, definitions, and lemmas in the most em- phatic (plain) style, and unnumbered rules in the less emphatic (definition) style. Definitions and lemmas are numbered consecutively within sections. You may also use the unnumbered Main Theorem. So, for example, you may have Definition 1.1, Definition 1.2 , Main Theorem, Rule, Lemma 1.3, Lemma 2.1, Theorem 1, and so on.
Example 3 \theoremstyle{plain}
\newtheorem{theorem}{Theorem} \newtheorem{corollary}{Corollary} \newtheorem*{main}{Main Theorem} \newtheorem{lemma}{Lemma} \newtheorem{proposition}{Proposition}
\theoremstyle{definition} \newtheorem{definition}{Definition}
\theoremstyle{remark} \newtheorem*{notation}{Notation}
With these proclamation definitions you can use theorems, corollaries, lemmas, and propositions in the most emphatic (plain) style, and an unnumbered Main Theo- rem. You can have definitions in the less emphatic (definition) style. All are sep-
arately numbered. So in the document you may have Definition 1, Definition 2, Main Theorem , Lemma 1, Proposition 1, Lemma 2, Theorem 1, Corollary 1, and so on. You can also have Notations which are unnumbered and typeset in the least emphatic (remark) style.
6.5 Proof environments 131
Number swapping Proclamations can be numbered on the left, as for instance, 3.2 Theorem. To ac-
complish this, type the \swapnumbers command before the \newtheorem command corresponding to the proclamation definition you want to change. This command af- fects all of the proclamation definitions that follow it, so the proclamation definitions in the preamble should be in two groups. The regular ones should be listed first, followed by the \swapnumbers command, then all the proclamations that swap numbers.
Do not swap numbers unless the publisher demands it. Custom theorem styles
You can define custom theorem styles with the \newtheoremstyle command. You should very seldom do this, the three theorem styles of the document class should suffice. For more detail, see [5].