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8.4 Pseudodifferential Operators with Symbols of Rational Type  465

                           and





                                   A Φ r R (v ⊗ δ)( )=  k R  ,   − (η , 0) v(η )dη
                                                  IR n−1
                           for L ≥ m +1 and   ∈ Ω. Hence, we may decompose Q in the form


                                                  L

                                         Qv( )=     Q m+1−j v( )+ A Φ r R (  ⊗ δ)( ) ,


                                                 j=0
                                                 (Ω). Therefore, with Lemma 8.4.8 we can estimate
                           where A Φ r ,R ∈L  m−L−1
                                           c
                           the last term on the right–hand side as
                             
ϕA Φ r ,R (v ⊗ δ)
  s−m− 1
                                                     n
                                            H     2 (IR )
                                                   ≤ c
v ⊗ δ
  m−L+ 1       ≤ c
v
 H m−L+1 (K)
                                                             H     2 (IR n−1 ×IR)
                           provided L>s +1.
                              Here, c = c(s, L, K, ϕ). We note that we need to consider ϕA Φ r ,R instead
                           of A Φ r R since the middle estimate is only valid if   varies in a compact subset
                           of Q. For the estimates of ϕQv, we use Lemma 8.4.9 and obtain


                                                          L

                               
ϕQv
|  s−m− 1          ≤     c j 
v
 H s−j (IR n−1 + c
v
 H s−L+1 (K)
                                                                          )

                                               n
                                      H    2 (IR ∩{  n ≤0})
                                                          j=0

                                                       ≤ c 
v
 H s (K)
                           if we choose L> max{s +1, 1}. The proof of estimate (8.4.34) follows in
                           exactly the same manner. This completes the proof of Theorem 8.4.7.
                           Corollary 8.4.12. The linear operator Q defined by (8.4.5) is a continuous

                                                                                  n
                                                          n
                                                                              ∞ ¯
                                                     ∞ ¯
                                          ∞
                           mapping from C (U r ) into C (IR ∩U r ) andalsointo C (IR ∩U r ) where
                                         0


                                                                                  +
                                                          −
                            ¯
                                    ¯
                           IR n  and IR n  denote the lower and upper closed half space, respectively.
                             −       +
                           The proof is an immediate consequence of Theorem 8.4.7 since s can be
                           chosen arbitrarily large in (8.4.33) and (8.4.34).
                              In order to extend Theorem 8.4.7 to sectional traces, let us introduce the
                           following definition.


                           Definition 8.4.2. For k ∈ IN 0 ,let V ∈ C k    (−ε, ε) , D (U r ) ,  n  → V (  n )
                           ∈D (U r ) be a family of distributions which are k times continuously differ-



                           entiable on   n ∈ (−ε, ε). Then for the distribution v ∈D (U r × (−ε, ε)
                           defined as


                                   v, ϕ  =   V (  n ) ,ϕ(•,  n ) d  n for ϕ ∈D U r × (−ε, ε) ,
                                          IR
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