کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4602352 1631167 2008 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Which 2-hyponormal 2-variable weighted shifts are subnormal?
موضوعات مرتبط
مهندسی و علوم پایه ریاضیات اعداد جبر و تئوری
پیش نمایش صفحه اول مقاله
Which 2-hyponormal 2-variable weighted shifts are subnormal?
چکیده انگلیسی

It is well known that a 2-hyponormal unilateral weighted shift with two equal weights must be flat, and therefore subnormal. By contrast, a 2-hyponormal 2-variable weighted shift which is both horizontally flat and vertically flat need not be subnormal. In this paper we identify a large class S of flat 2-variable weighted shifts for which 2-hyponormality is equivalent to subnormality. One measure of the size of S is given by the fact that within S there are hyponormal shifts which are not subnormal.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Linear Algebra and its Applications - Volume 429, Issues 8–9, 16 October 2008, Pages 2227-2238