In asymptotic expansions of resolvent traces \Tr(A(P-\lambda)^{-1}) for
classical pseudodifferential operators on closed manifolds, the coefficient
C0(A,P) of (−λ)−1 is of special interest, since it is the first
coefficient containing nonlocal elements from A; on the other hand if A=I
and P=D∗D it gives part of the index of D. C0(A,P) also equals the zeta
function value at 0 when P is invertible. C0(A,P) is a trace modulo local
terms, since C0(A,P)−C0(A,P′) and C0([A,A′],P) are local. By use of
complex powers Ps (or similar holomorphic families of order s), Okikiolu,
Kontsevich and Vishik, Melrose and Nistor showed formulas for these trace
defects in terms of residues of operators defined from A, A′, logP and
logP′.
The present paper has two purposes: One is to show how the trace defect
formulas can be obtained from the resolvents in a simple way without use of the
complex powers of P as in the original proofs. We here also give a simple
direct proof of a recent residue formula of Scott for C0(I,P). The other
purpose is to establish trace defect residue formulas for operators on
manifolds with boundary, where complex powers are not easily accessible; we do
this using only resolvents. We also generalize Scott's formula to boundary
problems.Comment: 41 page