An inverse problem in Polya-Schur theory. I. Non-genegerate and
degenerate operators
An inverse problem in Polya-Schur theory. I. Non-genegerate and
degenerate operators
Given a linear ordinary differential operator T with polynomial coefficients, we study the class of closed subsets of the complex plane such that T sends any polynomial (resp. any polynomial of degree exceeding a given positive integer) with all roots in a given subset to a polynomial with all roots …