9.4.4 Functional Names
Functions such as log and tan can't simply be typed in as log or tan otherwise they will come out looking like the variables l times o times g ( ) or t times a times n ( ). Instead you should use one of the commands listed in Table 9.5. The functions denoted with ^{†} can have limits by using the subscript command _ or the superscript command ^[Sub and superscript positioning for operators]. In addition, the modulo commands listed in Table 9.6 are also available.
\arccos 
\arcsin 
\arctan 

\arg 
\cos 
\cosh 

\cot 
\coth 
\csc 

\deg 
\det ^{†} 
\dim 

\exp 
\gcd ^{†} 
\hom 

\inf ^{†} 
\injlim ^{†‡} 
\ker 

\lg 
\lim ^{†} 
\liminf ^{†} 

\limsup ^{†} 
\ln 
\log 

\max ^{†} 
\min ^{†} 
\Pr ^{†} 

\projlim ^{†‡} 
\sec 
\sin 

\sinh 
\sup ^{†} 
\tan 

\tanh 
\varinjlim ^{†‡} 
\varliminf ^{†‡} 

\varlimsup ^{†‡} 
\varprojlim ^{†‡} 
Command  Example Input  Example Output 

\bmod 
$m \bmod n$ 

\pmod {<maths>} 
$m \pmod{n}$ 

\mod {<maths>}^{‡} 
$m \mod{n}$ 

\pod {<maths>}^{‡} 
$m \pod{n}$ 

Example (Trigonometric Functions):
This example uses the cos and sin functions and also the Greek letter theta.
Example (Limit):
The command \infty
is the
infinity symbol
, and the command \to
displays an
arrow pointing to the right. Note the use of _ since the
limit is a subscript.
which now displays as:
Example (With Subscript):
This is another example of a functional name using a subscript:
9.4.4.1 Defining New Functional Operators
It may be that you want a function that isn't specified in Table 9.5. In this case, the amsmath provides the preamble only command
or its starred variant
[Defining a new loglike function in LaTeX]Both versions define a command called <cmd>, which must start
with a backslash, that typesets <operator name> as a function
name. The starred version is for function names that can take
limits (like \lim
and \min
described above).
Example (Operator Without Limits):
Suppose I want a function called card, which represents the
cardinality of a set
. First I need to define the new
operator command (which I'm going to call \card
) in
the preamble:
This operator doesn't take any limits, so I have used the unstarred version.
Later in the document, I can use this new operator command:
\mathcal
is used as sets are
typically represented in a calligraphic font.
Example (Operator With Limits):
Suppose I now want a function called mode, which represents the mode of a set of numbers. First, I define the operator command in the preamble:
This operator needs to be able to have a subscript, so I have used the starred version.
Later in the document, I can use this new operator command:
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