Index commands

17.2 Index commands

There are a few major forms of \index commands. They are discussed in this section, illustrated by the commands shown in Section 17.1.

Simple \index commands The index entry

Foo, Soo-Key, 2 was created by command 9,

\index{Foo, Soo-Key} This entry is an example of the simplest form of an index command:

\index{entry } The entry

lattice, 2 was created as command 5,

\index{lattice|textbf} Ignore, for the time being, the |textbf part. This entry has a subentry,

lattice, 2 distributive, 2

which was created by command 6,

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\index{lattice!distributive} There is also a subsubentry,

lattice, 2 distributive, 2 complete, 2

which was created by command 7, \index{lattice!distributive!complete} The form of the \index command for subentries is \index{entry !subentry } and for subsubentries it is \index{entry !subentry !subsubentry }

Modifiers Command 5 \index{lattice|textbf}

produces a bold page number in the entry lattice. The command whose name follows the symbol | (in this case, the command name is textbf) is applied to the page number. For instance, if you want a large bold page number, then define the command \LargeBold as

\newcommand{\LargeBoldB}[1]{\textbf{\Large #1}} and type the \index command as \index{entry |LargeBold}

You can also modify \index commands to indicate page ranges: Main Theorem, 1

exposition, 1–2 The latter index entry has a page range. It was created with commands 3 and 8:

\index{Main Theorem!exposition|(} \index{Main Theorem!exposition|)}

17.2 Index commands 455

Separate an entry from its modifier with |, open the page range with (, and close it with ).

Modifiers can also be combined. The index commands \index{Main Theorem!exposition|(textbf}

\index{Main Theorem!exposition|)textbf} produce a bold page range.

Sorting control Observe the \index command

\index{pistar@$\Pi^{*}$ construction} This produces the entry

Π ∗ construction, 1 To place this entry in the correct place in the index, use a sort key. The general form of

an \index command with a sort key is \index{sortkey @entry } In this example, the sortkey is pistar. When the entries are sorted, the sortkey is

used to sort the entry. A few typical examples follow: Example 1 An \index command for G.I. ˇ Zitomirski˘ı,

\index{Zitomirskii@\v{Z}itomirski\u{\i}, G.I.} sorts ˇ Zitomirski˘ı with the Z entries.

If you used the command \index{\v{Z}itomirski\u{\i}, G.I.} Zitomirski˘ı would be sorted with the v’s. ˇ

Example 2 An \index command for the ˝ Ormester lemma, \index{Ormester@\H{O}rmester lemma} would sort ˝ Ormester lemma with the O entries.

If you used the command \index{\H{O}rmester lemma} Ormester lemma would be sorted with the H’s. ˝

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Example 3 An \index command for truncated lattice, \index{truncated lattice@\emph{truncated} lattice} sorts truncated lattice with the t entries.

If you use the command \index{\emph{truncated} lattice} this would sort truncated lattice with the e’s.

Example 4 We want to place the symbol Truncat f , typed as \Trunc f (see Sec- tion 7.6.2) in the index, sorted as Trunc.

\index{$\Trunc f$} would place Truncat f near the beginning of the index, sorted with the $ symbol.

If you use the command \index{Trunc@$\Trunc f$} this would sort Truncat f with the T’s.

Sorting control and subentries If you want to place a subentry under an entry with a sort key, you must include the

sort key part of the entry as well: \index{sortkey @entry !subentry } For instance, \index{Zitomirskii@\v{Z}itomirski\u{\i}, G.I.!education}

You can also use a sort key for subentries (and subsubentries), such as \index{lattice!weakly distributive@

\emph{weakly} distributive} or, a more complicated example, \index{Zitomirskii@\v{Z}itomirski\u{\i}, G.I.!elementary

education@\textbf{elementary} education}

17.2 Index commands 457

Special characters Since the !, @, and | characters have special meanings within an \index command,

you need to quote those characters if you want them to appear as themselves. MakeIn- dex uses the double quote character (") for this purpose: "!, "@, and "|.

Because this usage makes the double quote a special character itself, it also has to

be quoted if you need to use it in an \index command: "". Example 1 To produce the entry Start here!, type the \index command as

\index{Start here"!}

Example 2 To produce the entry @ symbol, type the \index command as \index{"@ symbol}

Example 3 To produce the entry |A|, type the \index command as \index{"|A"|@$"|A"|$}

Cross-references It is easy to make a cross-reference to another index entry. For instance, to list dis-

tributive lattice by cross-referencing it to lattice, distributive, the command is \index{distributive lattice|seeonly{lattice,

distributive}} which produces the entry

distributive lattice, see lattice, distributive For non-AMS document classes, seeonly should be see.

A command of this form can be placed anywhere in the document.

Tip Put all cross-referencing \index commands in one place in your document, so they are easy to keep track of.

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Placement of \index commands The principle is simple.

Rule

Placement of \index commands An \index command should:

1. Reference the correct page

2. Not introduce unwanted space into the typeset document

For example, you should avoid placing \index commands as shown here: Let $L$ be a distributive lattice

\index{lattice} \index{distributive lattice} that is strongly complete.

This placement may result in unwanted extra space following the word lattice: Let L be a distributive lattice that is strongly complete.

Note the placement of the \index commands in Section 17.1. In each case I have placed them as close to the referenced item as I could. If you place an index entry on a separate line, use % to comment out unwanted spaces including the end-of-line character (see Section 5.5.1), as in

Let $L$ be a distributive lattice \index{lattice}% \index{distributive lattice}% that is strongly complete.

Read also Section 18.5 on page breaks and index entries. Listing the forms of the \index command

We have discussed the following forms: \index{entry }

\index{entry !subentry } \index{entry !subentry !subsubentry } \index{entry |modifier } \index{entry |open/close modifier } \index{sortkey @entry }

17.3 Processing the index entries 459

\index{sortkey @entry !subentry } \index{sortkey @entry !subsortkey @subentry }

Of course, more combinations are possible; the following may be the longest form: \index{sortkey @entry !subsortkey @subentry %

!subsubsortkey @subsubentry |open/close modifier }