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On the convergence of biorthogonal series corresponding to nonselfadjoint Sturm-Liouville operator with discontinuous coefficients. (English) Zbl 0613.34021

Extending earlier work of V. A. Il’in [Mat. Zametki 22, 679-698 (1977; Zbl 0364.34011)], the author establishes an expansion theorem for eigenfunctions and associated functions (suitably defined) of the operator L, where \(Lu=(pu')'+qu\) almost everywhere on (a,b), p is a positive step function and q is a locally integrable complex-valued function.
Reviewer: A.L.Andrew

MSC:

34L99 Ordinary differential operators
42A20 Convergence and absolute convergence of Fourier and trigonometric series

Citations:

Zbl 0364.34011
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