Reid W.T. Sturmian Theory for Ordinary Differential Equations

Springer, 1980. — 575 p.The prime purpose of the present monograph is the presentation of a historical and comprehensive survey of the Sturmian theory for self-adjoint differential systems, and for this purpose the classical Sturmian theory is but an important special instance. On the othej hand, it is felt that
the Sturmian theory for a single real self-adjoint linear homogeneous ordinary differential equation must be given individual survey, for over the years it has continued to grow and continually provide impetus to the expansion of the subject for differential systems.
In the present treatment there has been excluded work on the extension of Sturmian theory to the areas of partial differential equations, and functional differential equations with delayed argument. Also, for ordinary differential equations the discussion and references on the asymptotic behavior of solutions has been limited to a very small aspect that is most intimately related to the oscillation theorems of the classical Sturmian theory.