A functional model for a commutative system of the linear bounded operators {T₁, T₂}, when T₁ is a contraction, is built.

For a commutative system of nonselfadjoint unbounded operators A₁, A₂ the concept of colligation and associated open system is given. For these open systems, the consistency conditions are established and the conservation ...

For an entirely non-selfadjoint operator with spectrum at zero, the imaginary component of which has an absolutely continuous spectrum (not necessarily dissipative and having lacunas in the spectrum), triangular and ...

A class of characteristic functions corresponding to commutative systems of unbounded nonselfadjoint operators is studied. The theorem on unitary equivalence is proved. The class of functions corresponding to these commutative ...