TITLE: What does "arg inf" mean?
QUESTION [9 upvotes]: I noticed this term on this post. 
But the term arg inf is not clearly defined.

REPLY [4 votes]: It refers to the argument of the function such that the function attains its infimum (or minimum). For example, let $f(x) = x^2-x$. Then $\arg\inf f(x) = {1\over 2}$ because $f(x)$ attains its minimum at $x= {1\over 2}$.