Label (of an Equation, Figure, Reference, etc.)

Number and/or prefix word placed at the beginning of display elements (for example, equation, statement, figure).


As an example, a label placed at the beginning of an equation (<disp-formula>) could be a number such as <label>Equation 3.</label>, <label>(3)</label>, or <label>3.</label>. A label before a statement such as a Proof or Lemma, could be a word such as <label>Proof</label> or <label>Hypothesis</label>.
Many objects can take explicit labels. For example, a <label> can contain the number or symbol used as a prefix character for a footnote that is placed at the point of the footnote reference. Similarly, the number and any prefix word associated with the title or the caption of a <fig> can be marked as a <label>, for example, “Figure 3.”, “Exhibit 2.”, or “3.”.
In Citations: A <label> can be used to preserve the prefix number for a reference or citation “25.” or “[Lapeyre 2010]”. This can be useful when reconstructing untagged cross-references.
Accessibility: Sometimes a <label> needs to be pronounced in a way that is not reflected in its content or its tagging. The @alt attribute can be used to record the pronunciation for screen readers and other accessibility devices. For example, the element figure that follows might be pronounced as “Figure 3”.
<label alt="figure 3">Fig&#x00A0;III.</label>


Content Model

<!ELEMENT  label        (#PCDATA %label-elements;)*                  >

Expanded Content Model

(#PCDATA | bold | fixed-case | italic | monospace | overline | roman | sans-serif | sc | strike | underline | ruby | alternatives | inline-graphic | private-char | chem-struct | inline-formula | sub | sup)*


This element may be contained in:

Example 1

For a table:
<table-wrap id="t2" orientation="portrait" position="float">
<label>Table II.</label>
<p>Models to approximate the bound frequencies as waves 
in X→M (<inline-graphic id="g1" xlink:href="d1"/>: Rotational, 
<inline-graphic id="g2" xlink:href="d2"/>: Vibrate in <italic>y</italic> 
direction, <inline-graphic id="g3" xlink:href="d3"/>: Vibrate in
<italic>x</italic> direction, <inline-graphic id="g4" xlink:href="d4"/>: 
Vibrate mainly in <italic>y</italic> direction including a small 
portion of vibration in <italic>x</italic> direction, 
<inline-graphic id="g5" xlink:href="d5"/>: Vibrate mainly in 
<italic>x</italic> direction including a small portion of vibration 
in <italic>y</italic> direction).</p>
<table border="1">...</table>

Example 2

For a figure:
<title>Outcome data</title>...
<p>Figure <xref ref-type="fig" rid="F2">2</xref> shows that
overall there was no significant difference between day hospital
and alternative forms ...</p>
<fig id="F2">
<label>Figure 2</label>
<caption><p>Odds of death or poor outcome in patients
receiving day hospital care or alternative services (random
effects model). Heterogeneity between trials is presented
as &#x03C7;<sup>2</sup></p></caption>
<graphic xmlns:xlink="http://www.w3.org/1999/xlink"
<fig id="f3" position="float">
<label>FIG. 3.</label>
<graphic specific-use="print" xlink:href="1.4821168.figures.highres.f3.zip"></graphic>
<graphic specific-use="online" xlink:href="1.4821168.figures.online.f3.jpg"></graphic>

Example 3

In a note:
<ref id="c35">
<p>The geometric optimization and electronic transport properties are 
all calculated by a developed <italic>ab-initio</italic> software package 
Atomistix ToolKit, which is based on the spin-polarized density-functional 
theory combined with the non-equilibrium Greens functions. ...</p>

Example 4

In an element-style bibliographic reference (punctuation and spacing removed):
<ref id="B8">
<element-citation publication-type="journal">
<person-group person-group-type="author">
<article-title>Effects and costs of day-care
services for the chronically ill: a randomized
<source>Medical Care</source>
<year iso-8601-date="1980">1980</year>
<pub-id pub-id-type="pmid">6772889</pub-id>

Example 5

In a mixed-style bibliographic reference (punctuation and spacing preserved):
<ref id="B1">
<mixed-citation publication-type="book">
<collab>Research Unit of the Royal College of Physicians
and British Geriatric Society</collab>.
<source>Geriatric day hospitals: their role and guidelines
for good practice</source>. <publisher-loc>London</publisher-loc>:
<year iso-8601-date="1994">1994</year>.

Example 6

For a hypothesis:
<article dtd-version="1.1">
<p>Industrial buyers categorise foreign countries
according to their level of technological achievement
and subsequently differentiate their perceptions of
these countries accordingly. ... The following
hypothesis is posited:
<statement><label>Hypothesis 1</label>
<p>Buyer preferences for companies are influenced 
by factors extrinsic to the firm attributable to, and
determined by, country-of-origin effects.</p>