Arg max
The notation
arg max (or
argmax) in mathematical descriptions stands for the
argument of the maximum, that is to say, the value of the given
argument for which the value of the given expression attains its
maximum value. This is well-defined only if the maximum is reached at a single value. Thus
holds
if and only if x0 is the unique value of
x for which
f(
x) is maximized.
arg min (or argmin) is defined analogously.