🏗️ $\Theta \rho ϵ\eta \Pi \alpha \tau \pi$🚧 (under construction)

Suppose that a set $A$ is in 1-1 correspondence with $A_1\times A_2\times \dots \times A_n$, then $\left|A\right|={\prod }_{i=1}^n\left|A_i\right|$