Properties of critical and subcritical second order self-adjoint linear equations
Necessary and/or sufficient conditions guaranteeing criticality (subcriticality) of the equation \(a_{n-1}y_{n-1}+b_ny_n+a_ny_{n+1}=0\), \(n\in\mathbb{Z}\), are established. Further, the fourth order equation \(-\Delta^4 y_n+\Delta(r_{n+1}\Delta y_{n+1})=0\), \(r_n>0\), \(n\in\mathbb{Z}\), is considered, and its 1-criticality is proved.
scientific article; zbMATH DE number 7438446
scientific article