equation-figure

Darwin Information Typing Architecture (DITA) Version 1.3 Part 3: All-Inclusive Edition

version
1.3
author
OASIS DITA Technical Committee

Use the equation-figure element to represent an equation that functions as form of figure or display. Display equations are intended to be numbered when numbering is desired.

Since the equation-figure element is specialized from fig, display equations can have titles, descriptions, figure groups, and all other figure components. The direct children of equation-figure can be the equation content itself (for example, mathml or an image reference), or it can be one or more equation-block elements, along with other elements allowed within fig, such as paragraphs.

When an equation-figure element has multiple direct child mathml, image, or pre elements, each child represents an alternative form of the equation. Processors are free to choose the form or forms that they use in deliverables. For example, if there is both an image and MathML markup, an HTML-generating processor could output both the image reference and the MathML with appropriate HTML class or id values to enable dynamic showing or hiding of one form or the other based on browser capability. All other direct-child elements of equation-figure are treated normally.

When the intent is to have equations combined with other commentary within an equation-figure, the recommended best practice is to use child equation-block elements to contain the equations and clearly distinguish them from the commentary.

Inheritance

+ topic/fig equation-d/equation-figure

Example

In the following example, the equation-figure element contains a title and MathML:
<equation-figure>
  <title>Display equation with a MathML container</title>
  <mathml>
    <m:math display='block'>
      <m:semantics>
        <m:mrow>
          <m:mfrac>
            <m:mrow>
              <m:mi>n</m:mi><m:mo>!</m:mo>
            </m:mrow>
            <m:mrow>
              <m:mi>r</m:mi><m:mo>!</m:mo><m:mrow><m:mo>(</m:mo>
                <m:mrow>
                  <m:mi>n</m:mi><m:mo>&#x2212;</m:mo><m:mi>r</m:mi>
                </m:mrow>
                <m:mo>)</m:mo></m:mrow><m:mo>!</m:mo>
            </m:mrow>
          </m:mfrac>         
        </m:mrow>
      </m:semantics>
    </m:math>
  </mathml>
</equation-figure>
In the following example, the equation-figure element contains a title and an equation-block element that contains MathML and commentary:
<equation-figure>
  <title>Display equation with a MathML container</title>
  <equation-block>
    <mathml>
      <m:math display='block'>
        <m:semantics>
          <m:mrow>
            <m:mfrac>
              <m:mrow>
                <m:mi>n</m:mi><m:mo>!</m:mo>
              </m:mrow>
              <m:mrow>
                <m:mi>r</m:mi><m:mo>!</m:mo><m:mrow><m:mo>(</m:mo>
                  <m:mrow>
                    <m:mi>n</m:mi><m:mo>&#x2212;</m:mo><m:mi>r</m:mi>
                  </m:mrow>
                  <m:mo>)</m:mo></m:mrow><m:mo>!</m:mo>
              </m:mrow>
            </m:mfrac>            
          </m:mrow>
        </m:semantics>
      </m:math>
    </mathml>
  </equation-block>
  <p>Where 
<equation-inline><mathml><m:math><m:mi>r</m:mi></m:math></mathml></equation-inline>
is greater than 1.</p>
</equation-figure>

Attributes

The following attributes are available on this element: Universal attribute group, Display attribute group, outputclass, and spectitle.