Some Properties of the Exchange Operator with respect to Structured Matrices defined by Indefinite Scalar Product Spaces

2015 ◽  
Vol 30 ◽  
Author(s):  
Hanz Martin Cheng ◽  
Roden Jason David

The properties of the exchange operator on some types of matrices are explored in this paper. In particular, the properties of exc(A,p,q), where A is a given structured matrix of size (p+q)×(p+q) and exc : M ×N×N → M is the exchange operator are studied. This paper is a generalization of one of the results in [N.J. Higham. J-orthogonal matrices: Properties and generation. SIAM Review, 45:504–519, 2003.].

2017 ◽  
Vol 5 (1) ◽  
pp. 225-241
Author(s):  
Frank J. Hall ◽  
Zhongshan Li ◽  
Caroline T. Parnass ◽  
Miroslav Rozložník

Abstract This paper builds upon the results in the article “G-matrices, J-orthogonal matrices, and their sign patterns", Czechoslovak Math. J. 66 (2016), 653-670, by Hall and Rozloznik. A number of further general results on the sign patterns of the J-orthogonal matrices are proved. Properties of block diagonal matrices and their sign patterns are examined. It is shown that all 4 × 4 full sign patterns allow J-orthogonality. Important tools in this analysis are Theorem 2.2 on the exchange operator and Theorem 3.2 on the characterization of J-orthogonal matrices in the paper “J-orthogonal matrices: properties and generation", SIAM Review 45 (3) (2003), 504-519, by Higham. As a result, it follows that for n ≤4 all n×n full sign patterns allow a J-orthogonal matrix as well as a G-matrix. In addition, the 3 × 3 sign patterns of the J-orthogonal matrices which have zero entries are characterized.


2004 ◽  
Vol 385 ◽  
pp. 187-213 ◽  
Author(s):  
D.Steven Mackey ◽  
Niloufer Mackey ◽  
Françoise Tisseur

1999 ◽  
Vol 302-303 ◽  
pp. 77-104 ◽  
Author(s):  
Cornelis V.M. van der Mee ◽  
André C.M. Ran ◽  
Leiba Rodman

2016 ◽  
Vol 2016 ◽  
pp. 1-3 ◽  
Author(s):  
Hal Caswell ◽  
Silke F. van Daalen

The vec operator transforms a matrix to a column vector by stacking each column on top of the next. It is useful to write the vec of a block-structured matrix in terms of the vec operator applied to each of its component blocks. We derive a simple formula for doing so, which applies regardless of whether the blocks are of the same or of different sizes.


1997 ◽  
Vol 261 (1-3) ◽  
pp. 91-141 ◽  
Author(s):  
Yuri Bolshakov ◽  
Cornelis V.M. van der Mee ◽  
AndréC.M. Ran ◽  
Boris Reichstein ◽  
Leiba Rodman

Author(s):  
Yuri Bolshakov ◽  
Cornelis V. M. van der Mee ◽  
André C. M. Ran ◽  
Boris Reichstein ◽  
Leiba Rodman

2005 ◽  
Vol 27 (3) ◽  
pp. 821-850 ◽  
Author(s):  
D. Steven Mackey ◽  
Niloufer Mackey ◽  
Françoise Tisseur

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