Results 21 to 30 of about 19,039,568 (311)
Free products of cyclic groups in groups of infinite unitriangular matrices
Математичні Студії, 2023 Groups of infinite unitriangular matrices over associative unitary rings are considered. These groups naturally act on infinite dimensional free modules over underlying rings. They are profinite in case underlying rings are finite.
A. Oliynyk
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A characteristic quantity of P-matrices
Applied Mathematics Letters, 2002 zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Naihua Xiu, Jianzhong Zhang 0001
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A novel series of compositionally biased substitution matrices for comparing
BMC Bioinformatics, 2008 Background The most common substitution matrices currently used (BLOSUM and PAM) are based on protein sequences with average amino acid distributions, thus they do not represent a fully accurate substitution model for proteins characterized by a biased ...
Pizzi Elisabetta, Brick Kevin
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Pathological rate matrices: from primates to pathogens
BMC Bioinformatics, 2008 Background Continuous-time Markov models allow flexible, parametrically succinct descriptions of sequence divergence. Non-reversible forms of these models are more biologically realistic but are challenging to develop.
Knight Rob +4 more
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Linear Algebra and its Applications, 1979 AbstractSuppose F is a differentiable mapping from a rectangle R⊂En into En. Gale and Nikaido proved that if the Jacobian of F is a P-matrix in R, then F is univalent in R. Their paper has served as the basis of numerous results on univalence. Recently H.
Garcia, C.B., Zangwill, W.I.
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BMC Cancer, 2009 Background Interactions between cancer cells and stroma are critical for growth and invasiveness of epithelial tumors. The biochemical mechanisms behind tumor-stromal interactions leading to increased invasiveness and metastasis are mostly unknown.
Valianou Matthildi +4 more
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The Number of P-Vertices of Singular Acyclic Matrices: An Inverse Problem
Discussiones Mathematicae Graph Theory, 2020 Let A be a real symmetric matrix. If after we delete a row and a column of the same index, the nullity increases by one, we call that index a P-vertex of A.
Du Zhibin, da Fonseca Carlos M.
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Linear Algebra and its Applications, 2003 A real matrix \(A\in M_n(R)\) is called a \(P\)-matrix if all its principal minors are positive. In this paper the author considers the \(P\)-problem, namely the problem of checking whether a given matrix is a \(P\)-matrix. In Sections 2 and 3, he investigates some necessary and sufficient conditions for a real matrix to be a \(P\)-matrix, basing on ...
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Nonnegative Infinite Matrices that Preserve (p,q)-Convexity of Sequences
Abstract and Applied Analysis, 2017 This paper deals with matrix transformations that preserve the (p,q)-convexity of sequences. The main result gives the necessary and sufficient conditions for a nonnegative infinite matrix A to preserve the (p,q)-convexity of sequences.
Chikkanna R. Selvaraj, Suguna Selvaraj
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The performance of the Congruence Among Distance Matrices (CADM) test in phylogenetic analysis
BMC Evolutionary Biology, 2011 Background CADM is a statistical test used to estimate the level of Congruence Among Distance Matrices. It has been shown in previous studies to have a correct rate of type I error and good power when applied to dissimilarity matrices and to ultrametric ...
Lapointe François-Joseph +2 more
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