ZMod.card

theorem ZMod.card : ∀ (n : ℕ) [inst : Fintype (ZMod n)], Fintype.card (ZMod n) = n

The theorem `ZMod.card` states that for any natural number `n`, given that the set of integers modulo `n` (denoted as `ZMod n`) is a finite set (indicated by `[inst : Fintype (ZMod n)]`), the number of elements in this set, or its 'cardinality' (given by `Fintype.card (ZMod n)`), is equal to `n` itself. In other words, the set of integers modulo `n` has exactly `n` distinct elements.

More concisely: The theorem `ZMod.card` asserts that the cardinality of the set of integers modulo a natural number `n` is equal to `n`, provided that `ZMod n` is a finite type.