Mathematical notation for distinct numbers How can I represent a set of distinct numbers in shorthand mathematical notation? In particular I am trying to write that there are 4 distinct integers $a,b,c,d$.
For three numbers, I could say:
$a,b,c \in \mathbb{Z} :a \not= b\not= c \not=a$; however, for larger sets, I need to compare every pair of numbers for a total of $\frac{n!}{2}$comparisons. 
Is there an accepted notation for distinctness? Or could I make a statement such as $a,b,c,d \in \mathbb{Z}, \{a,b,c,d\}$ is a set, bearing in mind that sets cannot have duplicates?

Hint: Recall that both representations
\begin{align*}
\{1,1,2,3\}=\{1,2,3\}
\end{align*}
are valid and denote the same set. So this is not the appropriate notation for your needs.

It's common to use the phrase pairwise distinct for instance
  
  
*
  
*Let $a,b,c,d\in\mathbb{Z}$ denote pairwise distinct integers which ...
  
  
  The idea behind this phrase is that whenever we select two of the elements under consideration then they are different.

