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Version: DocBook V4.5

equation

equation — A displayed mathematical equation

Synopsis​

Content Model​

equation ::=
(blockinfo?,
 (title,titleabbrev?)?,
 (informalequation|
  (alt?,
   (graphic+|mediaobject+|mathphrase+))))

Attributes​

Common attributes

Name

Type

Default

floatstyle

CDATA

None

label

CDATA

None

Description​

An Equation is a formal mathematical equation (with an optional rather than required title).

If the MathML Module is used, Equation can also contain the mml:math element.

Processing expectations​

Formatted as a displayed block. For an inline equation, use InlineEquation.

Processing systems that number equations or build a table of equations at the beginning of a document may have difficulty correctly formatting documents that contain both Equations with Titles and Equations without Titles. You are advised to use InformalEquation for equations without titles.

Future Changes​

In some future version of DocBook, probably V5.0, even though the change has not yet been announced, the Title on Equation will be required. For equations without titles, use InformalEquation.

Parents​

These elements contain equation: answer, appendix, article, bibliodiv, bibliography, blockquote, callout, caution, chapter, constraintdef, glossary, glossdef, glossdiv, important, index, listitem, msgexplan, msgtext, note, para, partintro, preface, procedure, qandadiv, qandaset, question, refsect1, refsect2, refsect3, refsection, refsynopsisdiv, revdescription, sect1, sect2, sect3, sect4, sect5, section, setindex, sidebar, simplesect, step, taskprerequisites, taskrelated, tasksummary, tip, warning.

Children​

The following elements occur in equation: alt, blockinfo, graphic, informalequation, mathphrase, mediaobject, title, titleabbrev.

Attributes​

label

Label specifies an identifying string for presentation purposes.

Generally, an explicit Label attribute is used only if the processing system is incapable of generating the label automatically. If present, the Label is normative; it will used even if the processing system is capable of automatic labelling.

See Also​

example, figure, informalequation, informalexample, informalfigure, informaltable, inlineequation, subscript, superscript, table.

Examples​

<!DOCTYPE equation PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
          "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
<equation><title>Fermat's Last Theorem</title>
  <alt>x^n + y^n &ne; z^n &forall; n &gt; 2</alt>
  <graphic fileref="figures/fermat.png"/>
</equation>

Equation 1. Fermat's Last Theorem

Alternatively, for relatively simple equations such as Fermat's Last Theorem, mathphrase is often sufficient:

<!DOCTYPE equation PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
          "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
<equation><title>Fermat's Last Theorem</title>
  <alt>x^n + y^n &ne; z^n &forall; n &gt; 2</alt>
  <mathphrase>x<superscript>n</superscript>
+ y<superscript>n</superscript>
≠ z<superscript>n</superscript>
∀ n ≠ 2</mathphrase>
</equation>

Equation 2. Fermat's Last Theorem

xn + yn ≠ zn ∀ n ≠ 2