English

Wronskians and deep zeros of holomorphic functions

Complex Variables 2013-08-15 v1 Functional Analysis

Abstract

Given linearly independent holomorphic functions f0,...,fnf_0,...,f_n on a planar domain Ω\Omega, let E\mathcal E be the set of those points zΩz\in\Omega where a nontrivial linear combination j=0nλjfj\sum_{j=0}^n\lambda_jf_j may have a zero of multiplicity greater than nn, once the coefficients λj=λj(z)\lambda_j=\lambda_j(z) are chosen appropriately. An elementary argument involving the Wronskian WW of the fjf_j's shows that E\mathcal E is a discrete subset of Ω\Omega (and is actually the zero set of WW); thus "deep" zeros are rare. We elaborate on this by studying similar phenomena in various function spaces on the unit disk, with more sophisticated boundary smallness conditions playing the role of deep zeros.

Keywords

Cite

@article{arxiv.1210.1277,
  title  = {Wronskians and deep zeros of holomorphic functions},
  author = {Konstantin M. Dyakonov},
  journal= {arXiv preprint arXiv:1210.1277},
  year   = {2013}
}

Comments

22 pages; to appear in J. Math. Pures Appl