On the maximum rank of a real binary form

被引:16
作者
Causa, A. [1 ]
Re, R. [1 ]
机构
[1] Univ Catania, Dipartimento Matemat & Informat, I-95125 Catania, Italy
关键词
Typical rank; Waring rank; Real roots;
D O I
10.1007/s10231-010-0137-2
中图分类号
O29 [应用数学];
学科分类号
070104 ;
摘要
We show that a real binary form f of degree n has n distinct real roots if and only if for any (alpha, beta) is an element of R(2)\{0} all the forms alpha f(x) + beta f(y) have n - 1 distinct real roots. This answers to a question of Comon and Ottaviani (On the typical rank of real binary forms, available at arXiv:math/0909.4865, 2009), and allows to complete their argument to show that f has symmetric rank n if and only if it has a distinct real roots.
引用
收藏
页码:55 / 59
页数:5
相关论文
共 4 条
[1]  
Alexander J., 1995, J. Algebraic Geom., V4, P201
[2]   On the Alexander-Hirschowitz theorem [J].
Brambilla, Maria Chiara ;
Ottaviani, Giorgio .
JOURNAL OF PURE AND APPLIED ALGEBRA, 2008, 212 (05) :1229-1251
[3]  
COMAS G, 2001, RANK BINARY FORM
[4]  
Comon P., 2009, TYPICAL RANK REAL BI