English

Cyclic polynomials in anisotropic Dirichlet~spaces

Complex Variables 2015-12-16 v1

Abstract

Consider the Dirichlet-type space on the bidisk consisting of holomorphic functions f(z1,z2):=k,l0aklz1kz2lf(z_1,z_2):=\sum_{k,l\geq 0}a_{kl}z_1^kz_2^l such that k,l0(k+1)α1(l+1)α2akl2<.\sum_{k,l\geq 0}(k+1)^{\alpha_1} (l+1)^{\alpha_2}|a_{kl}|^2 <\infty. Here the parameters α1,α2\alpha_1,\alpha_2 are arbitrary real numbers. We characterize the polynomials that are cyclic for the shift operators on this space. More precisely, we show that, given an irreducible polynomial p(z1,z2)p(z_1,z_2) depending on both z1z_1 and z2z_2 and having no zeros in the bidisk: if α1+α21\alpha_1+\alpha_2\leq 1, then pp is cyclic; if α1+α2>1\alpha_1+\alpha_2>1 and min{α1,α2}1\min\{\alpha_1,\alpha_2\}\leq 1, then pp is cyclic if and only if it has finitely many zeros in the two-torus T2\mathbb T^2; if min{α1,α2}>1\min\{\alpha_1,\alpha_2\}>1, then pp is cyclic if and only if it has no zeros in T2\mathbb T^2.

Keywords

Cite

@article{arxiv.1512.04871,
  title  = {Cyclic polynomials in anisotropic Dirichlet~spaces},
  author = {Greg Knese and Lukasz Kosinski and Thomas J. Ransford and Alan Sola},
  journal= {arXiv preprint arXiv:1512.04871},
  year   = {2015}
}

Comments

23 pages

R2 v1 2026-06-22T12:10:28.898Z