Abstract
A method to obtain bounds for the number of solutions with regular behaviour at infinity of selfadjoint ordinary differential equations is given. In this method, which is presented for a polar problem, the sequence of nested ellipsoids in a previous paper of mine is replaced by the use of certain projections. At the same time I take the opportunity to complete the unsatisfactory bibliography of my earlier paper.
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References
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Pleijel, Å. Complementary remarks about the limit point and limit circle theory. Ark. Mat. 8, 45–47 (1969). https://doi.org/10.1007/BF02589534
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DOI: https://doi.org/10.1007/BF02589534