scholarly journals Lower bounds for the condition number of a real confluent Vandermonde matrix

2006 ◽  
Vol 75 (256) ◽  
pp. 1987-1995 ◽  
Author(s):  
Ren-Cang Li
1987 ◽  
Vol 52 (3) ◽  
pp. 241-250 ◽  
Author(s):  
Walter Gautschi ◽  
Gabriele Inglese

Author(s):  
Stefan Kunis ◽  
Dominik Nagel

Abstract We prove upper and lower bounds for the spectral condition number of rectangular Vandermonde matrices with nodes on the complex unit circle. The nodes are “off the grid,” pairs of nodes nearly collide, and the studied condition number grows linearly with the inverse separation distance. Such growth rates are known in greater generality if all nodes collide or for groups of colliding nodes. For pairs of nodes, we provide reasonable sharp constants that are independent of the number of nodes as long as non-colliding nodes are well-separated.


SIAM Review ◽  
1996 ◽  
Vol 38 (2) ◽  
pp. 314-314
Author(s):  
Bradley K. Alpert

2020 ◽  
Vol 15 (1) ◽  
pp. 174-178
Author(s):  
Antonio J. Di Scala ◽  
Carlo Sanna ◽  
Edoardo Signorini

AbstractRecently, Blanco-Chacón proved the equivalence between the Ring Learning With Errors and Polynomial Learning With Errors problems for some families of cyclotomic number fields by giving some upper bounds for the condition number Cond(Vn) of the Vandermonde matrix Vn associated to the nth cyclotomic polynomial. We prove some results on the singular values of Vn and, in particular, we determine Cond(Vn) for n = 2kpℓ, where k, ℓ ≥ 0 are integers and p is an odd prime number.


Author(s):  
Parinya CHALERMSOOK ◽  
Hiroshi IMAI ◽  
Vorapong SUPPAKITPAISARN

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