A Paraproduct?
نویسندگان
چکیده
The term paraproduct is nowadays used rather loosely in the literature to indicate a bilinear operator that, although noncommutative, is somehow better behaved than the usual product of functions. Paraproducts emerged in J.-M. Bony’s theory of paradifferential operators [1], which stands as a milestone on the road beyond pseudodifferential operators pioneered by R. R. Coifman and Y. Meyer in [3]. Incidentally, the Greek word παρα (para) translates as beyond in English, and au délà de in French, just as in the title of [3]. The defining properties of a paraproduct should therefore go beyond the desirable properties of the product. As a first step and to illustrate these properties, let us consider the bilinear operator
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