“…Their study is also motivated by many linear and nonlinear problems in which multilinear operators naturally appear as terms of series expansions. This last point of view was pioneered and extensively pursued by Coifman and Meyer in [13], [14], [15], [16], and [47]. See also the work of Coifman, Deng, and Meyer [8], Fabes, Jerison, and Kenig [21], and Christ and Kiselev [7] where multilinear operators are used in the study of specific problems in partial differential equations.…”