 for any region \(V\) (of non-zero measure). If we now associate the glass with the phase space \(X\) and replace the scotch \(S\) and the volume \(V\) with two arbitrary subsets \(A\) and \(B\) of \(X\), then we get the general definition of what is called strong mixing (often also referred to just as ‘mixing’): a system is strong mixing iff