I'm working on a project that involves that set $P = \{\{n_1, \ldots, n_k\} \mid k \in \mathbb{N}, n_i \in \mathbb{N} \text{ and } n_1 + \cdots +n_k = n\}$ of all integer partitions of a number $n$. Is there a standard notation for this?
I know that $p(n)$ is commonly used to denote the number of integer partitions of $n$, but that's not what I'm looking for and I didn't find any standard notation for $P$.