ThmDex – An index of mathematical definitions, results, and conjectures.
Result R4147 on D2758: Cylinder set
Not all subsets of a cartesian product need be cylinder sets
Formulation 0
Let $X : = \{ 0, 1 \}$ be a D11: Set such that
(i) \begin{equation} Y : = \{ (0, 1), (1, 0) \} \end{equation}
Then
(1) \begin{equation} Y \subseteq X \times X \end{equation}
(2) \begin{equation} \forall \, E, F \subseteq X : Y \neq E \times F \end{equation}