These commands produce roman function names in math mode with proper spacing.
\arccos Inverse cosine
\arcsin Inverse sine
\arctan Inverse tangent
\arg Angle between the real axis and a point in the complex plane
\bmod Binary modulo operator, used as in \( 5\bmod 3=2 \)
\cos Cosine
\cosh Hyperbolic cosine
\cot Cotangent
\coth Hyperbolic cotangent
\csc Cosecant
\deg Degrees
\det Determinant
\dim Dimension
\exp Exponential
\gcd Greatest common divisor
\hom Homomorphism
\inf Infinum
\ker Kernel
\lg Base 2 logarithm
\lim Limit
\liminf Limit inferior
\limsup Limit superior
\ln Natural logarithm
\log Logarithm
\max Maximum
\min Minimum
\pmod Parenthesized modulus, as used in \( 5\equiv 2\pmod 3 \)
\Pr Probability
\sec Secant
\sin Sine
\sinh Hyperbolic sine
\sup sup
\tan Tangent
\tanh Hyperbolic tangent
The amsmath package adds improvements on some of these, and also allows you to define your own. The full documentation is on CTAN, but briefly, you can define an identity operator with \DeclareMathOperator{\identity}{id} that is like the ones above but prints as ‘id’. The starred form \DeclareMathOperator*{\op}{op} sets any limits above and below, as is traditional with \lim, \sup, or \max.
© 2007–2018 Karl Berry
Public Domain Software
http://latexref.xyz/Math-functions.html