Canonical forms and discrete Liouville–Green asymptotics for second-order linear difference equations

Abstract

Liouville-Green (WKB) asymptotic approximations are constructed for some classes of linear second-order difference equations. This is done starting from certain "canonical forms" for the three-term linear recurrence. Rigorous explicit bounds are established for the error terms in the asymptotic approximations of recessive as well as dominant solutions. The asymptotics with respect to parameters affecting the equation is also discussed. Several illustrative examples are given.