Luis González

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Many strategies for constructing different structures of sparse approximate inverse preconditioners for large linear systems have been proposed in the literature. In a more general framework, this paper analyzes the theoretical effectiveness of the optimal preconditioner (in the Frobenius norm) of a linear system over an arbitrary subspace of Mn (R). For(More)
Approximate inverses, based on Frobenius norm minimization, of real non-singular matrices are analyzed from a purely theoretical point of view. In this context, this paper provides several sufficient conditions, that assure us the possibility of improving (in the sense of the Frobenius norm) some given approximate inverses. Moreover, the optimal approximate(More)
The first pan-European harmonized active epidemiological surveillance program on honeybee colony mortality (EPILOBEE) was set up across 17 European Member States to estimate honeybee colony mortality over winter and during the beekeeping season. In nine Member States, overwinter losses were higher and statistically different from the empirical level of 10 %(More)
Alumni and Friends of the University of Kansas Department of Geology: Welcome to the first issue of The KU Geologic Record, the newsletter focusing on special accomplishments of University of Kansas Department of Geology students and faculty. The KU Department of Geology is fortunate to have high-caliber faculty and students. The faculty continue to provide(More)