Iwashita, Hirokazu Spectral theory for symmetric systems in an exterior domain. (English) Zbl 0655.35059 Tsukuba J. Math. 11, 241-256 (1987). The author studies spectral problems for the operator \[ H(x,D)u=\sum^{n}_{j=1}A_ j(x)\partial u/\partial x_ j+C(x)u\quad (x\in \Omega) \] in an exterior domain \(\Omega\) of \({\mathbb{R}}^ n\); here \(u=(u_ 1,...,u_ d)\) is a \({\mathbb{C}}^ d\)-valued function, and \(A_ j\) and C are \(d\times d\)-matrix valued coefficients. The basic tool is the commutator method developed by E. Mourre [Commun. Math. Phys. 78, 391-408 (1981; Zbl 0489.47010)]. Reviewer: J.Appell Cited in 1 ReviewCited in 5 Documents MSC: 35P05 General topics in linear spectral theory for PDEs 35F05 Linear first-order PDEs Keywords:exterior domain; matrix valued coefficients; commutator method Citations:Zbl 0489.47010 PDFBibTeX XMLCite \textit{H. Iwashita}, Tsukuba J. Math. 11, 241--256 (1987; Zbl 0655.35059) Full Text: DOI