[texhax] big-O, little-o notation

[John Wheeler]

Thanks to all who answered concerning Big-O, little-o notation.
Distilling the various answers, my own solution, within AMSmath,
is to put in the preamble:

\DeclareMathOperator{\BigO}{O}
\DeclareMathOperator{\littleo}{o}

which essentially defines \BigO as \mathrm{O}, etc.

and allows for the author to choose between (,); \bigl(,\bigr); or
\left(,\right) for delimiters, as needed.

Ross Moore's solution

\providecommand{\OO}[1]{\operatorname{O}\bigl(#1\bigr)}

with usage

$\OO{f(n)}$

is elegant, and has a number of nice features, but is less flexible
in allowing for really big arguments in a displayed equation.

John Wheeler
jcw at chemj2.ucsd.edu