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Operator matrix of Moore-Penrose inverse operators on Hilbert C*-modules

Mehdi Mohammadzadeh Karizaki, Mahmoud Hassani, Maryam Amyari, Maryam Khosravi (2015)

Colloquium Mathematicae

We show that the Moore-Penrose inverse of an operator T is idempotent if and only if it is a product of two projections. Furthermore, if P and Q are two projections, we find a relation between the entries of the associated operator matrix of PQ and the entries of associated operator matrix of the Moore-Penrose inverse of PQ in a certain orthogonal decomposition of Hilbert C*-modules.

Optimal design in small amplitude homogenization

Grégoire Allaire, Sergio Gutiérrez (2007)

ESAIM: Mathematical Modelling and Numerical Analysis

This paper is concerned with optimal design problems with a special assumption on the coefficients of the state equation. Namely we assume that the variations of these coefficients have a small amplitude. Then, making an asymptotic expansion up to second order with respect to the aspect ratio of the coefficients allows us to greatly simplify the optimal design problem. By using the notion of H-measures we are able to prove general existence theorems for small amplitude optimal design and to provide...

Pairs of k -step reachability and m -step observability matrices

Augusto Ferrante, Harald K. Wimmer (2013)

Special Matrices

Let V and W be matrices of size n × pk and qm × n, respectively. A necessary and sufficient condition is given for the existence of a triple (A,B,C) such that V a k-step reachability matrix of (A,B) andW an m-step observability matrix of (A,C).

Positive splittings of matrices and their nonnegative Moore-Penrose inverses

Tamminana Kurmayya, Koratti C. Sivakumar (2008)

Discussiones Mathematicae - General Algebra and Applications

In this short note we study necessary and sufficient conditions for the nonnegativity of the Moore-Penrose inverse of a real matrix in terms of certain spectral property shared by all positive splittings of the given matrix.

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