Results 11 to 20 of about 1,499,755 (333)

Miscellaneous equalities for idempotent matrices with applications

open access: yesOpen Mathematics, 2020
This article brings together miscellaneous formulas and facts on matrix expressions that are composed by idempotent matrices in one place with cogent introduction and references for further study.
Tian Yongge
doaj   +1 more source

Characterizations of the group invertibility of a matrix revisited

open access: yesDemonstratio Mathematica, 2022
A square complex matrix AA is said to be group invertible if there exists a matrix XX such that AXA=AAXA=A, XAX=XXAX=X, and AX=XAAX=XA hold, and such a matrix XX is called the group inverse of AA.
Tian Yongge
doaj   +1 more source

Block Matrix Formulations for Evolving Networks [PDF]

open access: yesSIAM Journal on Matrix Analysis and Applications, 2017
18 pages, 2 ...
Fenu, Caterina, Higham, Desmond J.
openaire   +6 more sources

Experimental and modeling study on the effect of molecular diffusion during CO2 injection

open access: yesPetroleum Research, 2021
In this work, a new approach based on the effect of molecular diffusion on oil recovery during CO2 injection in naturally fractured reservoirs has been proposed to examine the best condition for oil recovery in the matrix block.
Vahid Moayedi Esfahani   +3 more
doaj   +1 more source

Real block-circulant matrices and DCT-DST algorithm for transformer neural network

open access: yesFrontiers in Applied Mathematics and Statistics, 2023
In the encoding and decoding process of transformer neural networks, a weight matrix-vector multiplication occurs in each multihead attention and feed forward sublayer.
Euis Asriani   +4 more
doaj   +1 more source

USE OF THE TREND-FACTOR MODEL TO IMPROVE THE ACCURACY FORECASTS

open access: yesСтатистика и экономика, 2016
In this paper we propose a method toimprove the accuracy of the trend-factormodel on the assumption that the increasein endogenous variable-screens dependnot only on time but also deviations fromtheir trend of exogenous variables, provedby the ...
Irina V. Orlova, Viktor B. Turundaevsky
doaj   +1 more source

Identities and exponential bounds for transfer matrices [PDF]

open access: yes, 2012
This paper is about analytic properties of single transfer matrices originating from general block-tridiagonal or banded matrices. Such matrices occur in various applications in physics and numerical analysis.
Molinari, Luca G
core   +2 more sources

Many-Body Density Matrices for Free Fermions [PDF]

open access: yes, 2003
Building upon an analytical technique introduced by Chung and Peschel [M. Chung and I. Peschel, Phys. Rev. B 64, art. 064412 (2001)], we calculated the density matrix rho_B of a finite block of B sites within an infinite system of free spinless fermions.
Cheong, Siew-Ann, Henley, Christopher L.
core   +1 more source

On fast multiplication of a matrix by its transpose [PDF]

open access: yes, 2020
We present a non-commutative algorithm for the multiplication of a 2x2-block-matrix by its transpose using 5 block products (3 recursive calls and 2 general products) over C or any finite field.We use geometric considerations on the space of bilinear ...
Dumas, Jean-Guillaume   +2 more
core   +3 more sources

A note on the formulas for the Drazin inverse of the sum of two matrices

open access: yesOpen Mathematics, 2019
In this paper we derive the formula of (P + Q)D under the conditions Q(P + Q)P(P + Q) = 0, P(P + Q)P(P + Q) = 0 and QPQ2 = 0. Then, a corollary is given which satisfies the conditions (P + Q)P(P + Q) = 0 and QPQ2 = 0. Meanwhile, we show that the additive
Liu Xin, Yang Xiaoying, Wang Yaqiang
doaj   +1 more source

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