for r1, r2, r3, r4, r5, r6 being Real st r1 < r2 & r3 <= r4 & r5 < r6 holds
(L[01] (r1,r2,r3,r4)) * (L[01] (r5,r6,r1,r2)) = L[01] (r5,r6,r3,r4)