文摘
Let , for tR, be the pseudo-differential operator and let be the set of Schatten–von Neumann operators of order p[1,∞] on L2. We are especially concerned with the Weyl case (i.e. when t=1/2). We prove that if m and g are appropriate metrics and weight functions respectively, hg is the Planck's function, for some k0 and aS(m,g), then , iff aLp. Consequently, if 0δ<ρ1 and , then is bounded on L2, iff aL∞.