On the C<sup>*</sup>-comparison algebra of a class of singular Sturm-Liouville expressions on the real line


Abstract


In this article we study a C<sup>*</sup>-comparison algebra in the sense of [C2] with generators related to the ordinary differential expression H on the full real line R where,with constants 𝛼≥ 0, 𝛽∈ R, (1.1) (Error rendering LaTeX formula) More precisely, the algebra, called \mathbf A, is generated by the multiplications a( M) : u( x) → a(x)u(x), by functions a(x)∈ C([-∈fty,+∈fty]) and the (singular integral) operators(Error rendering LaTeX formula),and their adjoints. Here Λ = H<sup>-1/2</sup>, the inverse positive square root of the unique self-adjoint realization H of the expression (1.1), in the Hilbert space \mathbf H = L<sup>2</sup> ( R ) .(We use the same notation for both, (1.1) and its realization.) The case of 𝛽 < 𝛼+ 1 was discussed earlier in [Tg1], even for all n-dimensional problem. The commutators are compact and the Fredholm properties of operators in \mathbf A are determined by a complex-valued symbol on a symbol space homeomorphic to that of the usual Laplace comparison algebra on R<sup>n</sup>, although the symbol itself is calculated by different formulas.

DOI Code: 10.1285/i15900932v11p93

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