Year: 2026
Type: article
Abstract: We consider Widom factors for two extremal problems on compact sets $K\subset\mathbb R$: the $L^{2}$ Widom factors $W_{2,n}(\mu_{K})$ of monic orthogonal polynomials with respect to the equilibrium measure $\mu_{K}$, and the residual Widom factors $W_{\infty,n}^{(x_{0})}(K)$ for residual polynomials normalized at an exterior point $x_{0}\notin K$. Using weakly equilibrium Cantor sets $K(\gamma)$, we prove that for any sequence $(c_{n})$ with subexponential growth there exists a non-polar $K(\gamma)$ such that $W_{2,n}(\mu_{K(\gamma)})\ge c_{n}$ for all $n$. Moreover, for each $x_{0}\in\mathbb R\setminus K(\gamma)$ we obtain power-type lower bounds of the form $W_{\infty,n}^{(x_{0})}(K(\gamma))\geq c_{n}^{\tau_{x_{0}}}$ with $\tau_{x_{0}}\in(0,1)$, holding for all $n$ in unbounded gaps and along a subsequence in bounded gaps.
Author: Gökalp Alpan
Institution: Sabancı Üniversitesi
Language: English
Subfield: Applied Mathematics
Field: Mathematics
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4416050548