This is a simple notation question about something I seem to have forgotten, have a complete mental block to remembering, and can't find online. I think there's an equally simple answer.
Suppose I have (for instance) a set $S$ and some injective function $f:S\rightarrow\mathbb{R}$. There's a standard notation to indicate the minimum value that $f$ takes on the elements of $S$: $$\underset{x\in S}{\rm{min}}\{f(x)\}.$$ But what if, instead, I want to indicate the element of $S$ that achieves this minimal value? I could just write $$\{x\in S\mid f(x)\text{ is minimal}\}$$ but I feel like there is a better notation, resembling the one above, that I cannot remember.