TL;DR: A family of semi-norms is defined, subject to some interpolating conditions, providing interpolation methods that preserve polynomials of degree≤m−1 and converge in Sobolev spaces Hm+s(Ω).
Abstract: We define a family of semi-norms ‖μ‖m,s=(∫ℝ n∣τ∣2s∣ℱ Dmu(τ)∣2 dτ)1/2 Minimizing such semi-norms, subject to some interpolating conditions, leads to functions of very simple forms, providing interpolation methods that: 1°) preserve polynomials of degree≤m−1; 2°) commute with similarities as well as translations and rotations of ℝn; and 3°) converge in Sobolev spaces Hm+s(Ω).
TL;DR: In this paper, the symbolic calculus is developed further than in [6], and an index formula for elliptic problems, extending the results of [3] and [6] is derived.
Abstract: which will contain at least the operator describing a classical boundary problem, and also i ts parametr ix in the elliptic case. In fact what we construct there is one of the smallest possible \"algebras\" tha t will work. In tha t respect, our result is less general than tha t of Vi~ik and Eskin [10]. The difference lies in the fact tha t in our problem, the pseudo-differential appearing in (0.1) (coefficient A) has to satisfy a supplementary condition along the boundary: the transmission property. (1) The operators tha t arise in (0.1) have already been described in [6] (where we also require analyticity). In this work, we only require tha t the operators preserve locally Coo functions. The symbolic calculus is developed further than in [6], and we derive an index formula for elliptic problems, extending tha t of [3]. Roughly speaking, the coefficient A in (0.1)is a sum A = P + G , whereP is a pseudodifferential operator satisfying the transmission condition (w 2), and G (which we call a singular Green operator -w 3) is an operator which takes any distribution into a function which is C ~ inside ~ (but may be irregular at the boundary): such operators arise for
TL;DR: In this paper, continuity for weighted modulation spaces is discussed, and it is shown that many such spaces can be obtained in a canonical way from the corresponding standard modulation spaces, and the trace operator a↦a(0, ·) acting on modulationspaces.