I have a set $A = \{S_1, S_2,..., S_N\}$. Each $S_x$ element of set $A$ is another set, such that: $S_x = \{a\}$ or $S_x = \{a,b\}$ or $S_x = \{a,b,c\}$ or $S_x = \{a,b,c,d\}$.
I was wondering whether I could use an alternative notation for the internal sets, instead of curly brackets, without creating any confusion. For example, could I denote them as tuples (even though the order of the elements does not matter), i.e: $S_x = (a)$ or $S_x = (a,b)$ or $S_x = (a,b,c)$ or $S_x = (a,b,c,d)$.
The problem is, in case I use the above tuple notation, would it be correct to use the $\in$ operator as $a \in S_x$?
Is there a better way to tackle this?
Please note that I need to use the $\in$ operator for the elements of the internal sets, e.g. $a \in S_x$.