But simple formulas with one alphabet and a huge number of symbols
are not sufficient for mathematicians to expose their thoughts
properly. They tend to use every available typeface to denote
special things.
To cope with this need for special alphabets in formulas,' we introduce
the concept of 〈<#489#>#tex2html_accent_inline1455#<#489#>. These constructs are
special commands which switch to a specific typeface. They might
correspond to different typefaces in different math versions but
within one version they always select the same typeface regardless of
surrounding conditions.
A 〈<#490#>#tex2html_accent_inline1457#<#490#> can be defined according to
the users' needs but standard LATEX<#241#><#241#> already has a few of them built
in. They are described in table~#tab:math-id#242>.
<#1458#>#tex2html_accent_inline1459#<#1458#>:
<#1460#>Predefined 〈<#492#>#tex2html_accent_inline1462#<#492#> in LATEX<#1460#>
| #tablestar243# |
When using such an 〈<#493#>#tex2html_accent_inline1467#<#493#> two
syntax variants are available: one can understand a
command like 72 as a switch to a different
font, i.e. using a syntax 73 as the
old LATEX<#250#><#250#> does, but we prefer to view the
〈<#494#>#tex2html_accent_inline1469#<#494#> as a command with one
argument, i.e. to use a syntax of the form
74 To select the first alternative a
style option `<#252#>#tex2html_accent_inline1470#<#252#>' is provided. This option
is automatically selected if the `<#253#>#tex2html_accent_inline1471#<#253#>' option
is used since this option is supposed to produce
identical results for older documents.
New 〈<#495#>#tex2html_accent_inline1473#<#495#> are defined in
two steps. First the identifier is made known to the
system with the 75 command. Then
specific typefaces in some or all 〈<#496#>#tex2html_accent_inline1475#<#496#>
are assigned by means of the 76
command.
Let us discuss this process in detail. Suppose that
you want to make a sans serif typeface available as a
math alphabet. First we choose a new command name
(e.g. 77) and tell LATEX<#256#><#256#> about it with
the line
verbatim74#
Then we consult table~#tab:fonts#259> to find suitable
fonts to assign to this alphabet identifier. As you
find out, the computer modern sans serif family
consists of three series, a medium, semi bold
condensed and a bold extended one. The medium and the
bold extended series both contain a normal shape
typeface. So we add the line:
verbatim75#
Now our alphabet identifier is ready for use in these two versions.
We demonstrate this with the formula
<#458#>#tex2html_accent_inline1476#<#458#>55
which was produced by
verbatim76#
Note that we first switched back to the normal version. This was
necessary since this article is typeset with a third version (Euler)
in force. If we had tried to use 78 in this version
we would have gotten an error message stating that this
〈<#497#>#tex2html_accent_inline1478#<#497#>
isn't defined for the Euler version.#tex2html_accent_inline1481#
If we are interested in a slanted shape we have to face a
problem: there is no slanted shape in the bold extended series of the
Computer Modern sans serif family. So, if we make the identifier
known only in the normal version then it would produce an error message
when encountered in the bold (or any other) version. Of course we
can get by
56
using always
the same typeface in all
versions. To make this task a bit easier there is also a 79
variant
of the 80 command which takes three more
arguments: the default values for family, series and shape for all
math versions in which the alphabet identifier is not explicitly
defined via an 81 command. So our second example
can be set up simply by stating
verbatim77#
This would have the additional advantage that this math alphabet
identifier is also allowed in math versions which are defined in style
files or document styles (like the Euler version mentioned earlier).
Any explicit 82 command overwrites the defaults
given by 83; so, it might be a good idea always
to specify default values.
Here we show the same formula as above, but this time in the Euler
version and with 84 instead of 85:
#math81#
#tex2html_wrap_indisplay1485##tex2html_wrap_indisplay1486#Ai = tanα