summaryrefslogtreecommitdiff
path: root/usergrps/uktug/baskervi/4_1/bailey.tex
diff options
context:
space:
mode:
Diffstat (limited to 'usergrps/uktug/baskervi/4_1/bailey.tex')
-rw-r--r--usergrps/uktug/baskervi/4_1/bailey.tex115
1 files changed, 115 insertions, 0 deletions
diff --git a/usergrps/uktug/baskervi/4_1/bailey.tex b/usergrps/uktug/baskervi/4_1/bailey.tex
new file mode 100644
index 0000000000..8897edeca4
--- /dev/null
+++ b/usergrps/uktug/baskervi/4_1/bailey.tex
@@ -0,0 +1,115 @@
+%%% An item for Topical Tips
+\title{Topical tip: Numbering theorems and corollaries in \LaTeX}
+\newtheorem{prequestion}{Question}
+\newtheorem{preanswer}{Answer}
+\renewcommand{\thepreanswer}{}
+\newenvironment{question}{\begin{prequestion}\rm}{\end{prequestion}}
+%%%
+%%% Dear Mr Editor, I should like the content of questions and answers
+%%% to come out in what all copy-editors call ROMAN, not in what
+%%% Frank Mittelbach calls roman. And this should be irrespective
+%%% of the surrounding text.
+%%%
+\newenvironment{answer}{\begin{preanswer}\rm}{\end{preanswer}}
+\author[R.~A.~Bailey]{R.~A.~Bailey\\Goldsmiths' College, University of London}
+%%%
+\newcommand{\latexword}[1]{{\ttfamily\fontshape{n}{#1}}}
+%%% and the above should be in typewriter-ordinary IRRESPECTIVE of the
+%%% surrounding fonts
+%%%
+\newcommand{\theoremheadfont}[1]{\textbf{#1}}
+%%%
+%%% editor: I have been as generic as I can, but of course you can't
+%%% put \verb inside a \newcommand. I have consistently used + as the
+%%% delimiter for \verb.
+%%%
+\newcommand{\lamport}{{\itshape \LaTeX: A Document Preparation System\/} by Leslie
+Lamport}
+\newcommand{\shortlamp}{{\itshape The Manual}}
+
+\begin{Article}
+
+\begin{question}
+We Mathematicians can't use \LaTeX. We need to be able to choose how to label
+our theorems. For example, I like to have my important theorems numbered in a
+sequence Theorem~A, Theorem~B and so on,
+and the less important theorems numbered
+Theorem~1, Theorem~2 and so on. You can't do that in \LaTeX.
+\label{sieb}
+\end{question}
+
+\begin{answer}
+Oh yes you can, and using nothing more than you can find in
+\lamport, hereafter called \shortlamp.
+
+Pages 58--59 of \shortlamp\ show how to set up a simple theorem environment.
+The command
+\begin{verbatim}
+ \newtheorem{thm}{Theorem}
+\end{verbatim}
+creates an environment called \latexword{thm}. Then each use of this
+environment produces something whose heading is \theoremheadfont{Theorem}. It
+is true that these theorems are numbered 1, 2,~3, etc. To obtain something
+numbered A, B,~C, etc., use the numbering commands given on page~92 of
+\shortlamp. Thus
+\begin{verbatim}
+ \newtheorem{main}{Theorem}
+ \renewcommand{\themain}{\Alph{main}}
+\end{verbatim}
+creates an environment called \latexword{main} whose heading is also
+\theoremheadfont{Theorem} but whose instances are numbered A, B, \ldots.
+Cross-references work correctly too: if you label the third
+\latexword{main} with
+\verb+\label{mmm}+
+and refer to it with \verb+Theorem~\ref{mmm}+ then it will be called
+Theorem~C.
+\end{answer}
+
+\begin{question}
+Journal editors are so fussy. They all want me to number my corollaries in
+different ways. The first wants corollaries numbered in the same sequence as
+theorems; the second wants them numbered in a separate sequence of their own;
+the third wants the corollaries after Theorem~7 to be numbered Corollary~7.1,
+Corollary~7.2, etc.; while the fourth also wants the corollaries to start
+renumbering after each theorem, but wants the corollaries after Theorem~7 to be
+numbered Corollary~1, Corollary~2 etc. How do I do all of this?
+\end{question}
+
+\begin{answer}
+It is not hard to do these things, because \LaTeX\ is provided with the
+\latexword{newtheorem} command. I shall assume that you have defined an
+environment \latexword{thm} as in the answer to Question~\ref{sieb}. The
+instructions on pages~58--59 of \shortlamp\ show us how to satisfy the first
+three editors. For the first, put
+\begin{verbatim}
+ \newtheorem{cor}[thm]{Corollary}
+\end{verbatim}
+and you will get an environment called \latexword{cor} whose instances are
+called \theoremheadfont{Corollary} numbered in the same sequence as the
+theorems. For the second, put
+\begin{verbatim}
+ \newtheorem{cor}{Corollary}
+\end{verbatim}
+and for the third put
+\begin{verbatim}
+ \newtheorem{cor}{Corollary}[thm]
+\end{verbatim}
+
+For the fourth editor, we need the extra information from page~92. The third
+command above makes the \latexword{cor} counter start again after each
+\latexword{thm}, but it causes the Corollary number to be printed as, say, 7.1
+rather than~1. We can cure this by putting
+\begin{verbatim}
+ \newtheorem{cor}{Corollary}[thm]
+ \renewcommand{\thecor}{\arabic{cor}}
+\end{verbatim}
+
+In each of the four cases you get an environment called \latexword{cor}
+whose instances are
+called \theoremheadfont{Corollary}.
+Only the system of numbering is different.
+
+You should now be able to work out how to make the corollaries after Theorem~5
+come out as Corollary~5a, Corollary~5b, and so on.
+\end{answer}
+\end{Article}