Results 21 to 30 of about 594 (68)

Integrable discrete nets in Grassmannians

open access: yes, 2008
We consider discrete nets in Grassmannians $\mathbb{G}^d_r$ which generalize Q-nets (maps $\mathbb{Z}^N\to\mathbb{P}^d$ with planar elementary quadrilaterals) and Darboux nets ($\mathbb{P}^d$-valued maps defined on the edges of $\mathbb{Z}^N$ such that ...
A. Doliwa   +10 more
core   +1 more source

An algebraic model for the propagation of errors in matrix calculus

open access: yesSpecial Matrices, 2020
We assume that every element of a matrix has a small, individual error, and model it by an external number, which is the sum of a nonstandard real number and a neutrix, the latter being a convex (external) additive group.
Van Tran Nam, van den Berg Imme
doaj   +1 more source

Maximum nullity and zero forcing of circulant graphs

open access: yesSpecial Matrices, 2020
The zero forcing number of a graph has been applied to communication complexity, electrical power grid monitoring, and some inverse eigenvalue problems.
Duong Linh   +4 more
doaj   +1 more source

A matrix approach to determine optimal predictors in a constrained linear mixed model

open access: yesOpen Mathematics
For a general vector of all unknown vectors in a constrained linear mixed model (CLMM), this study compared the dispersion matrices of the best linear unbiased predictors with any symmetric matrix for determining the optimality of predictors among others.
Güler Nesrin, Büyükkaya Melek Eriş
doaj   +1 more source

The algebraic size of the family of injective operators

open access: yesOpen Mathematics, 2017
In this paper, a criterion for the existence of large linear algebras consisting, except for zero, of one-to-one operators on an infinite dimensional Banach space is provided. As a consequence, it is shown that every separable infinite dimensional Banach
Bernal-González Luis
doaj   +1 more source

On decompositions of estimators under a general linear model with partial parameter restrictions

open access: yesOpen Mathematics, 2017
A general linear model can be given in certain multiple partitioned forms, and there exist submodels associated with the given full model. In this situation, we can make statistical inferences from the full model and submodels, respectively.
Jiang Bo, Tian Yongge, Zhang Xuan
doaj   +1 more source

Topological entropy for locally linearly compact vector spaces and field extensions

open access: yesTopological Algebra and its Applications, 2020
Let 𝕂 be a discrete field and (V, ϕ) a pair consisting of a locally linearly compact 𝕂-space V and a continuous endomorphism ϕ: V → V. We provide the formulae to compute the topological entropy ent* of the flow (V, ϕ) subject to either extension or ...
Castellano Ilaria
doaj   +1 more source

On the Principal Permanent Rank Characteristic Sequences of Graphs and Digraphs

open access: yes, 2015
The principal permanent rank characteristic sequence is a binary sequence $r_0 r_1 \ldots r_n$ where $r_k = 1$ if there exists a principal square submatrix of size $k$ with nonzero permanent and $r_k = 0$ otherwise, and $r_0 = 1$ if there is a zero ...
Horn, Paul   +5 more
core   +1 more source

On the dimension of the algebraic sum of subspaces

open access: yesOpen Mathematics
We provide a recursive formula for the dimension of the algebraic sum of finitely many subspaces in a finite-dimensional vector space over an arbitrary field.
Makrides Gregoris, Szemberg Tomasz
doaj   +1 more source

Maximal contractive tuples

open access: yes, 2013
Maximality of a contractive tuple of operators is considered. Characterization of a contractive tuple to be maximal is obtained. Notion of maximality of a submodule of Drury-Arveson module on the $d$-dimensional unit ball $\mathbb{B}_d$ is defined.
Das, B. Krishna   +2 more
core   +1 more source

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