Logikai szita formula

A logikai szita formula két halmazra:

\( \mid A \cup B \mid = \mid A \mid + \mid B \mid - \mid A \cap B \mid \)

A logikai szita formula három halmazra:

\( \mid A \cup B \cup C \mid = \mid A \mid + \mid B \mid + \mid C \mid - \mid A \cap B \mid - \mid A \cap C\mid - \mid B \cap C \mid + \mid A \cap B \cap C \mid \)