It is easily seen that for every realisation r , the term in the parentheses must be less than or equal to unity, so that the result for the average is also less than (or equal to) unity. If we have four distinct times rather than three, we have K = C 12 + C 23 + C 34 − − C 14 ≤ ≤ 2 , and so on. These are the Leggett–Garg inequalities. They express the relation between the temporal correlations of ⟨ ⟨ Q ( start ) Q ( end ) ⟩ ⟩ and the correlations between successive times in going from the start to the end.