Left invertible quasi-isometric liftings

Abstract

Quasi-isometric liftings similar to isometries, for the operators similar to contractions in Hilbert spaces, are investigated. The existence of such liftings is established, and their applications are explored for specific operator classes, including quasicontractions. A particular focus is placed on operators that admit left invertible minimal quasi-isometric liftings. These operators are characterized within the framework of $A$-contractions, and the matrix structures of their liftings are analyzed, highlighting parallels with the isometric liftings of contractions.