Let $J$ be a
D11: Set such that
A
D1721: Random collection $X : J \to \mathsf{Random}(\Omega \to \Xi)$ is
exchangeable if and only if
\begin{equation}
\forall \, N \in 1, 2, 3, \ldots : \forall \, j_1, \dots, j_N \in J : \forall \, \sigma \in \mathsf{Per}(J) : (X_{j_1}, \dots, X_{j_N}) \overset{\mathsf{d}}{=} (X_{\sigma(j_1)}, \dots, X_{\sigma(j_N)})
\end{equation}
