کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4631173 1340617 2011 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
On numerical ranges of the compressions of normal matrices
موضوعات مرتبط
مهندسی و علوم پایه ریاضیات ریاضیات کاربردی
پیش نمایش صفحه اول مقاله
On numerical ranges of the compressions of normal matrices
چکیده انگلیسی
For an n × n normal matrix A, whose numerical range NR[A] is a k-polygon (k ⩽ n), an n × (k − 1) isometry matrix P is constructed by a unit vector υ∈Cn, and NR[P∗AP] is inscribed to NR[A]. In this paper, using the notations of NR[P∗AP] and some properties from projective geometry, an n × n diagonal matrix B and an n × (k − 2) isometry matrix Q are proposed such that NR[P∗AP] and NR[Q∗BQ] have as common support lines the edges of the k-polygon and share the same boundary points with the polygon. It is proved that the boundary of NR[P∗AP] is a differentiable curve and the boundary of the numerical range of a 3 × 3 matrix P∗AP is an ellipse, when the polygon is a quadrilateral.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Mathematics and Computation - Volume 217, Issue 9, 1 January 2011, Pages 4699-4709
نویسندگان
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