 Other properties are not shared by all natural language quantifiers but single out important subclasses. We mentioned two already in  section 2  above: symmetry and monotonicity. Typical symmetric quantifiers are some, no, at least five, exactly three, an even number of, infinitely many, whereas all, most, at most one-third of the are non-symmetric. Another way to express symmetry is to say that the truth-value of \(Q(A,B)\) only depends on the set \(A\cap B\). More precisely, call Q intersective if for all M and all \(A,A',B,B' \subseteq M\):