Generalized resolvents of symmetric and isometric operators‎: ‎the Shtraus approach

Abstract

‎This survey is devoted to the theory of Abram Vilgelmovich Shtraus‎ ‎and his disciples and followers‎. ‎This theory studies the so-called‎ ‎generalized resolvents of symmetric and isometric operators in a‎ ‎Hilbert space and provides alternative formulas to the well-known‎ ‎Krein-type formulas‎.