Let E be a Banach space.
We prove a representation theorem for functionals on L2(E) that are additive on
weakly orthogonal elements (as defind by Beck and Warren in Pacific J. Math. in
1972) and utilize the theorem to obtain a characterization theorem for linear
Gaussian stochastic processes on L2(E) that take independent values on weakly
orthogonal functions. This enables us give a new and very natural interpretation of
the notion of weak orthogonality.