Difference equations related to Jacobi-type pencils

On some classical type Sobolev orthogonal polynomials

“…Polynomials p n satisfy some special orthogonality relations as well as other interesting properties [17].…”

“…where p −2 (λ) = p −1 (λ) = 0, γ −2 = γ −1 = a −1 = β −1 = 0. Polynomials p n satisfy some special orthogonality relations as well as other interesting properties [17]. Another possible generalization of (3) of the following form:…”

“…Chaundy also trusted that the method and arguments in [5] could be enlarged to deal with equations of higher order. In [18] there appeared orthogonal polynomials which are solutions of a differential equation of the form (3) with ρ = 4, ξ = 2, and with ρ = 3, ξ = 1.…”