- Current Issue - Ahead of Print Articles - All Issues - Search - Open Access - Information for Authors - Downloads - Guideline - Regulations ㆍPaper Submission ㆍPaper Reviewing ㆍPublication and Distribution - Code of Ethics - For Authors ㆍOnlilne Submission ㆍMy Manuscript - For Reviewers - For Editors
 Weak and quadratic hyponormality of 2-variable weighted shifts and their examples Bull. Korean Math. Soc. 2017 Vol. 54, No. 2, 633-646 https://doi.org/10.4134/BKMS.b160231Published online January 4, 2017Printed March 31, 2017 Chunji Li Northeastern University Abstract : Recently, Curto, Lee and Yoon considered the properties (such as, hyponormality, subnormality, and flatness, etc.) for $2$-variable weighted shifts and constructed several families of commuting pairs of subnormal operators such that each family can be used to answer a conjecture of Curto, Muhly and Xia negatively. In this paper, we consider the weak and quadratic hyponormality of 2-variable weighted shifts $\left( W_{1},W_{2}\right)$. In addition, we detect the weak and quadratic hyponormality with some interesting 2-variable weighted shifts. Keywords : weakly hyponormal, quadratically hyponormal, 2-variable weighted shifts MSC numbers : Primary 47B37; Secondary 47B20 Downloads: Full-text PDF