\DeclareMathAlphabet {<math-alph>} {<encoding>} {<family>}
{<series>} {<shape>}
Defines <math-alph> to be a new math alphabet.
The arguments <encoding> <family> <series> <shape> are the
default values for this math alphabet in all math versions; these can
be reset later for a particular math version by a \SetMathAlphabet
command. If <shape> is empty then the <math-alph> is declared to
be invalid in all versions, unless it is set by a later
\SetMathAlphabet command.
Checks that <math-alph> can be used and that <encoding> is a valid encoding scheme.
In these examples, \foo is defined everywhere but \baz,
by default, is defined nowhere.
\DeclareMathAlphabet{\foo}{OT1}{cmtt}{m}{n}
\DeclareMathAlphabet{\baz}{OT1}{}{}{}
\SetMathAlphabet {<math-alph>} {<version-name>}
{<encoding>} {<family>} {<series>} {<shape>}
Changes, or sets, the font for the math alphabet <math-alph> in math version <version-name> to <encoding><family><series><shape>.
Checks that <math-alph> is a math alphabet, <version-name> is a math version and <encoding> is a known encoding scheme.
This example defines \baz for the `normal' math version only:
\SetMathAlphabet\baz{normal}{OT1}{cmss}{m}{n}
Note that this declaration is not used for all math alphabets:
Section 3.5 describes \DeclareSymbolFontAlphabet,
which is used to set up math alphabets contained in fonts which have
been declared as symbol fonts.