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?
$\endgroup$ 13 Answers
$\begingroup$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: $$\operatorname{argmax}_{j : N_j \in U_i} DA_j$$
$\endgroup$ 2 $\begingroup$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 $\max\{a,b\}$.)
$\endgroup$ 5 $\begingroup$\max which looks like "$\max$"
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