The Friedrichs extension of a class of discrete symplectic systems

The Friedrichs extension of minimal linear relation being bounded below and associated with the discrete symplectic system with a special linear dependence on the spectral parameter is characterized by using recessive solutions. This generalizes a similar result obtained by Došlý and Hasil for linear operators defined by infinite banded matrices corresponding to even-order Sturm–Liouville difference equations and, in a certain sense, also results of Marletta and Zettl or Šimon Hilscher and Zemánek for singular differential operators.