Mathematics for IGCSE & O level - Sets (Section 1 - No. 14)
Which statements describe properties of the empty set, represented by the symbol {} or ∅?
The empty set is a subset of every set.
The empty set is a set containing no elements.
The empty set is equal to the universal set.
The empty set has an infinite number of elements.
Giải thích
Empty sets have no members and are a subset of every set.