2026/01/07 by Zameddin I. Ismailov, Elif Otkun Çevik
Mathematics · #Mathematical Inequalities and Applications #Mathematical functions and polynomials #Analytic and geometric function theory
paper · doi:10.1080/03081087.2026.2613296
The primary objective of this study is to derive evaluation formulas for the lower and upper bounds of the joint δ-numerical radius and the joint δ-Crawford number functions. Subsequently, several significant estimates for these bounds are presented in the context of sectorial coordinate operators. The results obtained not only extend certain well-known findings in the recent literature but also contribute novel and practical insights to the field. Another aim of this work is to enrich the existing theory by offering alternative and useful results in this area.