∅ (constant)

The empty set.

Notes

When you want to denote the empty set, you may either use the standard set notation to write a set with zero elements, {}, or you may use the predefined constant ∅ which has this value: ∅ = {}.

Examples

∅ = {}

true

#∅

0

∀(∅, x ↦ even(x) ∧ odd(x))

true

∀(∅, x ↦ x.species = "elephant" ∧ x.color = color("pink") ∧ x.CanFly)

true