A note on block diagonal and block triangular preconditioners for complex symmetric linear systems
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DOI: 10.1007/s11075-018-0520-4
Abstract: In this note, the additive block diagonal preconditioner (Bai et al., Numer. Algorithms 62, 655–675 2013) and the block triangular preconditioner (Pearson and Wathen, Numer. Linear Algebra Appl. 19, 816–829 2012) are further studied and… read more here.
Keywords: note block; block; triangular preconditioners; block diagonal ... See more keywords
Graded identities and isomorphisms on algebras of upper block-triangular matrices
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DOI: 10.1016/j.jalgebra.2018.12.019
Abstract: Let $G$ be an abelian group and $\mathbb{K}$ an algebraically closed field of characteristic zero. A. Valenti and M. Zaicev described the $G$-gradings on upper block-triangular matrix algebras provided that $G$ is finite. We prove… read more here.
Keywords: matrix; graded identities; upper block; block triangular ... See more keywords
Approximation of pseudospectra of block triangular matrices
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DOI: 10.1016/j.laa.2020.08.008
Abstract: Abstract We approximate the pseudospectra of a block triangular matrix with two blocks on the diagonal in terms of the pseudospectra of its diagonal blocks. read more here.
Keywords: triangular matrices; pseudospectra block; block triangular; approximation pseudospectra ... See more keywords