HTML and CSS Reference
In-Depth Information
MathML has presentational, content, and mixing markup elements. There are two types of flavor for MathML markup.
The first one focuses on the display of equations, known as Presentation MathML . The second, Content MathML ,
stresses the semantic meaning of the mathematical annotation.
Similar to XHTML, there are two types of elements in MathML: the ones with the start and end tags and the
empty elements that are self-closing. However, the ratio of empty elements is much higher in MathML than in
XHTML. Elements can have optional attributes that consist of a name and a value (the latter one is quoted in double
or single quotes). The majority of MathML attribute values must be in a predetermined format such as a positive
integer or the keyword true .
In MathML there are container elements such as mrow (a group of subexpressions) and token elements such as mi
(identifier; i.e., a name of a constant, a variable, or a function). The element mo represents an operator (e.g., + ), a fence
(e.g., { ), or a separator (e.g., , ). Numeric literals are specified by mn . The proper use of mi , mo , and mn is vital to provide
adequate information for rendering engines to apply the correct typographic rules. Containers can contain other
elements only while token elements delimit plain-text characters, special entity references, or symbols (the smallest
units with meaning). Listing 3-57 shows an example.
Listing 3-57. A Simple Example for Container and Token Elements in MathML
Entity references begin with an ampersand ( & ) and end with a semicolon ( ; ). Beyond keywords such as &alpha; ,
a numeric format referring to the Unicode codepoint of the symbol is also allowed. More than 1,800 symbols are
The MathML namespace is . It can be declared in two ways: using the
xmlns attribute or an attribute with an xmlns prefix. In the first case, the default namespace applies to the element on
which it is provided, as well as all child elements (Listing 3-58).
Listing 3-58. A Presentation MathML Document Fragment Applying the MathML Namespace
<math mode="display" xmlns=" " >
<mo>&#xB1;<!--PLUS-MINUS SIGN--></mo>
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