A Marcinkiewicz type multiplier theorem for H¹ spaces on product domains
Tom 140 / 2000
Studia Mathematica 140 (2000), 273-287
DOI: 10.4064/sm-140-3-273-287
Streszczenie
It is proved that if $m : ℝ^d → ℂ$ satisfies a suitable integral condition of Marcinkiewicz type then m is a Fourier multiplier on the $H^1$ space on the product domain $ℝ^{d_1}×...×ℝ^{d_k}$. This implies an estimate of the norm $N(m,L^p(ℝ^d)$ of the multiplier transformation of m on $L^p(ℝ^d)$ as p→1. Precisely we get $N(m,L^p(ℝ^d))≲(p-1)^{-k}$. This bound is the best possible in general.
