  In many practical situations, we know the probabilities $a$ and $b$ of two
events $A$ and $B$, and we want to estimate the joint probability ${\rm
Prob}(A\,\&\,B)$. The algorithm that estimates the joint probability based on
the known values $a$ and $b$ is called an and-operation. An important case when
such a reconstruction is possible is when we know the correlation between $A$
and $B$; we call the resulting and-operation correlation-based. On the other
hand, in statistics, there is a widely used class of and-operations known as
copulas. Empirical evidence seems to indicate that the correlation-based
and-operation derived in https://doi.org/10.1007/978-3-031-08971-8_64 is a
copula, but until now, no proof of this statement was available. In this paper,
we provide such a proof.
