“…. , m, that act 1 This phrase means that the discrete-time processM = (M l ) l=0,...,J , whereM0 = 0 andM l is defined like the righthand side of (2.6) but with J j=1 being replaced by l j=1 and aj,r,s byãj,r,s is a martingale, which is a straightforward calculation.…”