“…Let χ 1 denote the space of equivalence classes of χ 0 1 modulo (•, •) 1 . There exist a unique isometry (which we again denote by) I 1 from χ 1 to L 2 1 obeying (1.4). Moreover, for every ϕ ∈ χ 0 1 , the process M ϕ t := I 1 (ϕ) = ϕ(x, s)1 s≤t dZ x,s is a martingale, and every L 2 1 -valued martingale can be represented in this form.…”