TITLE: what is the right symbol for the "max" like Pi is for product?
QUESTION [8 upvotes]: I have a set of variables that have a value, and i want to find the max of those values.  
Here is the equivalent of what I want to do with "sum"
$$\sum_{j:~N_j \in U_i}~ DA_j$$
For all j subject to $N_j \in U_i$, then sum $DA_j$.  Except I want a max.  What is the right symbol to use?

REPLY [14 votes]: If you are interested of the maximum value of $DA_j$ under the condition that $N_j \in U_i$ then you can use $\max$ as in: $$\max_{j : N_j \in U_i} DA_j$$
But if you are interested in the value of $j$ that makes $DA_j$ maximal, then you can use $\operatorname{argmax}$ as in: $$\operatorname{argmax}_{j : N_j \in U_i} DA_j$$

REPLY [11 votes]: Some people write
$$\bigvee_{j : N_j \in U_i} D A_j$$
with $\bigwedge$ for min.  I'm not convinced it's clearer than $\max$.  (The infix usage is more common, and more elegant looking: $a \vee b$ versus $\max\{a,b\}$.)