Differential operators generated by a countable number of quasi-differential expressions on the line. (English) Zbl 0723.34022
Self-adjoint realizations of differential expressions with a finite or countable number of interior singularities are characterized. This characterizations reduced to the well known Glazman-Krein-Naimark theory when there are no interior singularities present. For the case of an infinite number of singularities a new concept of a “maximality condition” plays a fundamental role.
Reviewer: A. Zettl (DeKalb)
MSC:
34B20 | Weyl theory and its generalizations for ordinary differential equations |
34B24 | Sturm-Liouville theory |