On the real line, let the Fourier transform of kn be k'n(ξ) = k'(ξ-n) where k'(ξ) is a smooth compactly supported function. Consider the bilinear operators Sn(f, g)(x) = ∫ f(x+y)g(x-y)kn(y) dy. If 2 ≤ p, q ≤ ∞, with 1/p + 1/q = 1/2, I prove that
Σ∞ n=-∞ ||Sn(f,g)||2 2 ≤ C2||f||p 2||g||q 2.
The constant C depends only upon k.
@article{urn:eudml:doc:41268, title = {On bilinear Littlewood-Paley square functions.}, journal = {Publicacions Matem\`atiques}, volume = {40}, year = {1996}, pages = {387-396}, mrnumber = {MR1425626}, zbl = {0869.42005}, language = {en}, url = {http://dml.mathdoc.fr/item/urn:eudml:doc:41268} }
Lacey, Michael T. On bilinear Littlewood-Paley square functions.. Publicacions Matemàtiques, Tome 40 (1996) pp. 387-396. http://gdmltest.u-ga.fr/item/urn:eudml:doc:41268/