Lp continuity of hörmander symbol operators [formula omitted] and numerical algorithm

Abstract

If we use Littlewood-Paley decomposition, there is no pseudo-orthogonality for Hörmander symbol operators O p S 0 , 0 m , which is different to the case S ρ , ∞ m . In this paper, we use a special numerical algorithm based on wavelets to study the L p continuity of non infinite smooth operators O p S 0 , 0 m ; in fact, we apply first special wavelets to symbol to get special basic operators, then we regroup all the special basic operators at given scale and prove that such scale operator's continuity decreases very fast, we sum such scale operators and a symbol operator can be approached by very good compact operators. By correlation of basic operators, we get very exact pseudo-orthogonality and also L 2 → L 2 continuity for scale operators. By considering the influence region of scale operator, we get H 1 ( = F 1 0 , 2 ) → L 1 continuity and L ∞ → BMO continuity. By interpolation theorem, we get also L p ( = F p 0 , 2 ) → L p continuity for 1 < p < ∞. Our results are sharp for F p 0 , 2 → L p continuity when 1 ≤ p ≤ 2, that is to say, we find out the exact order of derivations for which the symbols can ensure the resulting operators to be bounded on these spaces.