B, T and BT

Permitted Context: %math
Content Model: %math

These elements are used, when feasible, to alter the default fonts used to render variables and constants. Numbers, operators, delimiters and other symbols are unaffected. B renders its contents in bold, while T renders its contents in an upright font rather than an italic font. These can be nested to combine the effects, for a bold upright font. The BT element allows you to write <BT>term</BT> rather from having to write: <B><T>term</T></B>.

Permitted Attributes

This a space separated list of SGML NAME tokens and is used to subclass tag names. By convention, the class names are interpreted hierarchically, with the most general class on the left and the most specific on the right, where classes are separated by a period.

By using CLASS to describe the term as a vector, tensor or matrix etc. user agents can do a better job when rendering to non-visual media. Further conventions for term class names are not part of this specification.

Note: Don't use B for chemical formulae. These should be handled by subclassing the MATH element with class=chem, for instance: <MATH CLASS=CHEM>