equation — A displayed mathematical equation.


equation ::=


Common attributes and common linking attributes.

Additional attributes:

  • floatstyle
  • label
  • pgwide (enumeration)
    • “0”
    • “1”
  • type

Additional Constraints

  • example must not occur among the children or descendants of equation
  • figure must not occur among the children or descendants of equation
  • table must not occur among the children or descendants of equation
  • equation must not occur among the children or descendants of equation
  • If this element is the root element, it must have a version attribute.


An equation is a formal mathematical equation (with an optional rather than a 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.


Common attributes and common linking attributes.

any attribute

Any attribute in any other explicit namespace


Specifies style information to be used when rendering the float


Specifies an identifying string for presentation purposes


Indicates if the element is rendered across the column or the page

Enumerated values:

The element should be rendered in the current text flow (with the flow column width).


The element should be rendered across the full text page.


Identifies the type of equation


These elements contain equation: abstract, acknowledgements, annotation, answer, appendix, article, bibliodiv, bibliography, bibliolist, blockquote, callout, calloutlist, caption (db.caption), caution, chapter, colophon, constraintdef, danger, dedication, entry, example, figure, footnote, formalgroup, glossary, glossdef, glossdiv, glosslist, important, index, indexdiv, informalexample, informalfigure, itemizedlist, legalnotice, listitem, meta (db.meta.content), msgexplan, msgtext, note, orderedlist, para, partintro, preface, procedure, qandadiv, qandaset, question, refsect1, refsect2, refsect3, refsection, refsynopsisdiv, result, revdescription, sect1, sect2, sect3, sect4, sect5, section, setindex, sidebar, simplesect, step, taskprerequisites, taskrelated, tasksummary, td, textobject, th, tip, toc, tocdiv, topic, variablelist, warning.


The following elements occur in equation: alt, caption (db.caption), info (db.titleforbidden.info), info (db.titleonly.info), mathphrase, mediaobject, mml:*, title, titleabbrev.

See Also

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


 1 |<article xmlns='http://docbook.org/ns/docbook'>
   |<title>Example equation</title>
   |<equation xml:id="eq.fermat">
 5 |<title>Fermat's Last Theorem</title>
   |  <alt>x^n + y^n ≠ z^n ∀ n ≠ 2</alt>
   |  <mediaobject>
   |    <imageobject condition="print">
   |      <imagedata fileref="figs/print/db5d_refeqn01.pdf"/>
10 |    </imageobject>
   |    <imageobject condition="web">
   |      <imagedata fileref="figs/web/db5d_refeqn01.png"/>
   |    </imageobject>
   |  </mediaobject>
15 |</equation>
Equation 1Fermat's Last Theorem

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

 1 |<article xmlns='http://docbook.org/ns/docbook'>
   |<title>Example equation</title>
   |<equation xml:id="eq.fermat.mathphrase">
 5 |<title>Fermat's Last Theorem</title>
   |  <alt>x^n + y^n ≠ z^n ∀ n ≠ 2</alt>
   |  <mathphrase>x<superscript>n</superscript>
   |+ y<superscript>n</superscript>
   |≠ z<superscript>n</superscript>
10 |∀ n ≠ 2</mathphrase>
xn + yn ≠ zn ∀ n ≠ 2
Equation 2Fermat's Last Theorem