Let $X$ be a D17: Finite set such that
(i) | $K : = |X| \in \mathbb{N} = \{ 0, 1, 2, 3, \ldots \}$ |
(ii) | $X^N = \prod_{n = 1}^N X$ is a D326: Cartesian product |
(iii) | $\mathcal{R} : = \{ R : R \subseteq X^N \}$ is a D5494: Set of N-ary relations on $X^N$ |
Then
\begin{equation}
|\mathcal{R}| = 2^{K^N}
\end{equation}