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Wyszukujesz frazę "quadratic form" wg kryterium: Temat


Wyświetlanie 1-12 z 12
Tytuł:
Hermitian and quadratic forms over local classical crossed product orders
Autorzy:
Hatzaras, Y.
Theohari-Apostolidi, Th.
Powiązania:
https://bibliotekanauki.pl/articles/965780.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
crossed-product order
quadratic form
Opis:
Let R be a complete discrete valuation ring with quotient field K, L/K be a Galois extension with Galois group G and S be the integral closure of R in L. If a is a factor set of G with values in the group of units of S, then (L/K,a) (resp. Λ =(S/R,a)) denotes the crossed product K-algebra (resp. crossed product R -order in A). In this paper hermitian and quadratic forms on Λ -lattices are studied and the existence of at most two irreducible non-singular quadratic Λ -lattices is proved (Theorem 3.5). Further the orthogonal decomposition of an arbitrary non-singular quadratic Λ -lattice is given.
Źródło:
Colloquium Mathematicum; 2000, 83, 1; 43-53
0010-1354
Pojawia się w:
Colloquium Mathematicum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Distribution of Quadratic Form of Sample Mean and Variance
O rozkładzie formy kwadratowej średniej i wariancji z próby
Autorzy:
Wywiał, Janusz
Kończak, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/905703.pdf
Data publikacji:
2006
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
quadratic form
mean
variance
distribution
Opis:
The quadratic form of the sample mean and sample variance was considered. The sample is from normal distribution. The density function of the quadratic form has been derived. The quadratic form can be applied as the test statistic for the hypothesis on expected value and variance of normal distribution. The table with approximated critical values of the test statistic has been derived.
Źródło:
Acta Universitatis Lodziensis. Folia Oeconomica; 2006, 196
0208-6018
2353-7663
Pojawia się w:
Acta Universitatis Lodziensis. Folia Oeconomica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A mesh algorithm for principal quadratic forms
Autorzy:
Polak, A.
Powiązania:
https://bibliotekanauki.pl/articles/106252.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
mesh algorithm
quadratic form
quadratic diophantine equation
Opis:
In 1970 a negative solution to the tenth Hilbert problem, concerning the determination of integral solutions of diophantine equations, was published by Y. W. Matiyasevich. Despite this result, we can present algorithms to compute integral solutions (roots) to a wide class of quadratic diophantine equations of the form q(x) = d, where q : Z is a homogeneous quadratic form. We will focus on the roots of one (i.e., d = 1) of quadratic unit forms (q11 = ... = qnn = 1). In particular, we will describe the set of roots Rq of positive definite quadratic forms and the set of roots of quadratic forms that are principal. The algorithms and results presented here are successfully used in the representation theory of finite groups and algebras. If q is principal (q is positive semi-definite and Ker q={v ∈ Zn; q(v) = 0}= Z · h) then |Rq| = ∞. For a given unit quadratic form q (or its bigraph), which is positive semi-definite or is principal, we present an algorithm which aligns roots Rq in a Φ-mesh. If q is principal (|Rq| is less than ∞), then our algorithm produces consecutive roots in Rq from finite subset of Rq, determined in an initial step of the algorithm.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica; 2011, 11, 1; 23-31
1732-1360
2083-3628
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska. Sectio AI, Informatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure fractals and para-quaternionic geometry
Autorzy:
Ławrynowicz, Julian
Vaccaro, Massimo
Powiązania:
https://bibliotekanauki.pl/articles/747163.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
Fractal
quaternion
para-quaternion
Clifford structure
para-quaternionic structure
bilinear form
quadratic form
Opis:
It is well known that starting with real structure, the Cayley-Dickson process gives complex, quaternionic, and octonionic (Cayley) structures related to the Adolf Hurwitz composition formula for dimensions \(p = 2, 4\) and \(8\), respectively, but the procedure fails for \(p = 16\) in the sense that the composition formula involves no more a triple of quadratic forms of the same dimension; the other two dimensions are \(n = 2^7\). Instead, Ławrynowicz and Suzuki (2001) have considered graded fractal bundles of the flower type related to complex and Pauli structures and, in relation to the iteration process \(p \to p + 2 \to p + 4 \to ...\), they have constructed \(2^4\)-dimensional “bipetals” for \(p = 9\) and \(2^7\)-dimensional “bisepals” for \(p = 13\). The objects constructed appear to have an interesting property of periodicity related to the gradating function on the fractal diagonal interpreted as the “pistil” and a family of pairs of segments parallel to the diagonal and equidistant from it, interpreted as the “stamens”. The first named author, M. Nowak-Kepczyk, and S. Marchiafava (2006, 2009a, b) gave an effective, explicit determination of the periods and expressed them in terms of complex and quaternionic structures, thus showing the quaternionic background of that periodicity. In contrast to earlier results, the fractal bundle flower structure, in particular petals, sepals, pistils, and stamens are not introduced ab initio; they are quoted a posteriori, when they are fully motivated. Physical concepts of dual and conjugate objects as well as of antiparticles led us to extend the periodicity theorem to structure fractals in para-quaternionic formulation, applying some results in this direction by the second named author. The paper is concluded by outlining some applications.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica; 2011, 65, 2
0365-1029
2083-7402
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Jacobi type conditions for singular extremals
Autorzy:
Dmitruk, A. V.
Powiązania:
https://bibliotekanauki.pl/articles/969606.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
singular extremal
Goh transformation
Legendre quadratic form
Euler-Jacobi equation
conjugate point
Opis:
We consider the class of optimal control problems linear in the control, and study a singular extremal. If the Lagrange multipliers are unique, the quadratic order optimality conditions have the form of sign definiteness of a quadratic functional (the second variation of Lagrange function) with totally zero Legendre coefficient. Using the Goh transformation, we convert it to a functional possibly satisfying the strengthened Legendre condition, involving also an additional parameter, and by applying the Hestenes approach, determine its sign definiteness in terms of the conjugate point, i.e. give Jacobi type conditions.
Źródło:
Control and Cybernetics; 2008, 37, 2; 285-306
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Algorithms for integral solutions of a class of diophantine equations
Autorzy:
Polak, A.
Powiązania:
https://bibliotekanauki.pl/articles/206419.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
integral quadratic form
unit form
diophantine equations
roots
Euler bilinear form
Euclidean diagrams
mesh quiver
algorithm
Maple
Opis:
In 1970 a negative solution to the tenth Hilbert problem, concerning the determination of integral solutions of diophantine equations, has been published by Y. W. Matiyasevich (see Matiyasevich, 1970). Despite this result, we can present algorithms to compute integral solutions (roots) for a wide class of quadratic diophantine equations of the form q(x) = d, where q : Zn → Z is a homogeneous quadratic form. We will focus on the roots of one (i.e., d = 1) of quadratic Euler forms of selected posets from Loupias list (see Loupias, 1975). In particular, we will describe the roots of positive definite quadratic forms and the roots of quadratic forms that are principal (see Simson, 2010a). The algorithms and results we present here are successfully used in the representation theory of finite groups and algebras.
Źródło:
Control and Cybernetics; 2011, 40, 2; 491-514
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Second order conditions in optimal control problems with mixed equality-type constraints on a variable time interval
Autorzy:
Osmolovskii, N. P.
Powiązania:
https://bibliotekanauki.pl/articles/970741.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
piecewise continuous control
maximum principle
second order necessary or sufficient conditions
critical cone
quadratic form
Opis:
This paper provides an analysis of second-order necessary or sufficient optimality conditions of Pontryagin or bounded strong minima, for optimal control problems of ordinary differential equations, considered on a nonfixed time interval, with constraints on initial-final time-state as well as mixed state-control constraints of equality type satisfying condition of linear independence of gradients w.r.t. control.
Źródło:
Control and Cybernetics; 2009, 38, 4B; 1535-1556
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extension of the one-dimensional Stoney algorithm to a two-dimensional case
Autorzy:
Gniazdowski, Zenon
Powiązania:
https://bibliotekanauki.pl/articles/91318.pdf
Data publikacji:
2019
Wydawca:
Warszawska Wyższa Szkoła Informatyki
Tematy:
Stoney formula
Stoney equation
2D Stoney algorithm
tensor of curvature
stress in a thin film
anisotropy
quadric
quadratic form
Opis:
This article presents the extension of the one-dimensional Stoney algorithm to a two-dimensional case. The proposed extension consists in modifying the method of curvature estimation. The surface profile of the wafer before deposition of the thin film and after its deposition was locally approximated by the quadric. From this quadric, a quadratic form and the first degree surface were separated. An eigenproblem was solved for the matrix of this quadratic form. From eigenvectors a new coordinate system was created in which a new formula of the quadric was found. In this new coordinate system, the two-dimensional problem of estimating thecurvaturetensorhasbeensolvedbysolvingtwoindependentone-dimensional problems of curvature estimation. Returning to the primary coordinate system, in this primary system, a solution to the two-dimensional problem was obtained. The article proposes five versions of the two-dimensional Stoney algorithm, with diverse complexity and accuracy. The recommendation for the version of the algorithm that could be practically used was also presented.
Źródło:
Zeszyty Naukowe Warszawskiej Wyższej Szkoły Informatyki; 2019, 13, 20; 41-66
1896-396X
2082-8349
Pojawia się w:
Zeszyty Naukowe Warszawskiej Wyższej Szkoły Informatyki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Network optimality conditions
Autorzy:
Osmolovskii, Nikolai P.
Qian, Meizhi
Sokołowski, Jan
Powiązania:
https://bibliotekanauki.pl/articles/31343935.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
network
optimal control problem
weak local minimum
Pontryagin’s maximum principle
critical cone
quadratic form
second order optimality conditions
Riccati equation
Opis:
Optimality conditions for optimal control problems arising in network modeling are discussed. We confine ourselves to the steady state network models. Therefore, we consider only control systems described by ordinary differential equations. First, we derive optimality conditions for the nonlinear problem for a single beam. These conditions are formulated in terms of the local Pontryagin maximum principle and the matrix Riccati equation. Then, the optimality conditions for the control problem for networks posed on an arbitrary planar graph are discussed. This problem has a set of independent variables xi varying within their intervals [0, li], associated with the corresponding beams at network edges. The lengths li of intervals are not specified and must be determined. So, the optimization problem is non-standard, it is a combination of control and design of networks. However, using a linear change of the independent variables, it can be reduced to a standard one, and we show this. Two simple numerical examples for the single-beam problem are considered.
Źródło:
Control and Cybernetics; 2023, 52, 2; 129-180
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A second-order sufficient condition for a weak local minimum in an optimal control problem with an inequality control constraint
Autorzy:
Osmolovskii, Nikolai P.
Powiązania:
https://bibliotekanauki.pl/articles/2183496.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
critical cone
quadratic form
first order tangent
second order tangent
second order optimality conditions
weak local minimum
inequality control constraint
Pontryagin’s maximum principle
Opis:
This paper is devoted to a sufficient second-order condition for a weak local minimum in a simple optimal control problem with one control constraint G(u) ≤ 0, given by a C2-function. A similar second-order condition was obtained earlier by the author for a strong minimum in a much more general problem. In the present paper, we would like to take a narrower perspective than before and thus provide shorter and simpler proofs. In addition, the paper uses the first and second order tangents to the set U, defined by the inequality G(u) ≤ 0. The main difficulty of the proof, clearly shown in the paper, refers to the set, where the gradient Hu of the Hamiltonian is small, but the condition of quadratic growth of the Hamiltonian is satisfied. The paper can be valuable for self-explanation and provides a basis for extensions.
Źródło:
Control and Cybernetics; 2022, 51, 2; 151--169
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Second-order sufficient conditions for an extremum in optimal control
Autorzy:
Osmolovskij, N.
Powiązania:
https://bibliotekanauki.pl/articles/206727.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
ekstremala łamana
forma kwadratowa
minimum silne
minimum słabe
stożek krytyczny
warunek dostatecznej optymalności
zasada maksimum
accessory problem
broken extremal
control discontinuities
critical cone
maximum principle
quadratic form
strong minimum
suffcient optimality condition
weak minimum
Opis:
Suffcient quadratic optimality conditions for a weak and a strong minimum are stated in an optimal control problem on a fixed time interval with mixed state-control constraints, under the assumption that the gradients of all active mixed constraints with respect to control are linearly independent. The conditions are stated for the cases of both continuous and discontinuous controls and guarantee in each case a lower bound of the cost function increase at t1e reference point. They are formulated in terms of an accessory problem with quadratic form, which must be positive-definite on the so-called critical cone. In the case of discontinuous control the quadratic form has some new terms related to the control discontinuity.
Źródło:
Control and Cybernetics; 2002, 31, 3; 803-831
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Testing of the Prediction Unbiasedness on the Basis of Janus Quotient
O testowaniu nieobciążoności predykcji na podstawie współczynnika Janusowego
Autorzy:
Wywiał, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/1808297.pdf
Data publikacji:
2009-06-30
Wydawca:
Główny Urząd Statystyczny
Tematy:
test statistic
prediction error
unbiasednees
Janus quotient
quadratic form of normally distributed vector
approximation of distribution function
residual variance
prediction variance
Test statystyczny
błąd predykcji
nieobciążoność
współczynnik Janusowy
forma
kwadratowa wektora o rozkładzie normalnym
aproksymacja funkcji dystrybuanty
wariancja resztowa
wariancja predykcji
Opis:
The problem of choosing the appropriate predictor is being considered. Generally, in this paper the analysis is focused on the problem of unbiasedness of the predictors. Several tests attempting to verify the unbiasedness of three predictors of the linear trend are proposed. They are based on some modifications of the well-known Janus quotient being a ratio of the variance of prediction errors and the residual variance. In general each of the considered test statistic can be represented as the ratio of two quadratic forms of normal vectors. These two quadratic forms can be dependent, so its distribution function has to be approximated. An example of testing hypothesis on unbiasedness is presented. The obtained results can be generalized in the case of prediction on the basis of regression models.
W pracy jest rozważany problem wyboru odpowiedniego predykatora. Przyjęto, że postulowanym kryterium tego wyboru jest jego nieobciążoność. W pracy są proponowane testy na nieobciążoność predykcji trzech predyktorów trendu liniowego. Punktem wyjścia konstrukcji sprawdzianów testów jest znany współczynnik Janusowy używany do oceny dokładności ciągów wyznaczanych prognoz, który jest ilorazem wariancji predykcji ex-post i wariancji resztowej. Z formalnego punktu widzenia każdy z rozważanych sprawdzianów testów jest ilorazem dwóch form kwadratowych wektora zmiennych o rozkładzie normalnym. Te formy kwadratowe mogą być zależne. Dlatego w celu wyznaczenia rozkładu prawdopodobieństwa sprawdzianu testu jest adaptowana jedna ze znanych metod pozwalających na przybliżone wyliczanie wartości jego dystrybuanty. Rozważania zilustrowano przykładem. Otrzymane w pracy wyniki można uogólnić na przypadek predykcji na podstawie modelu regresji.
Źródło:
Przegląd Statystyczny; 2009, 56, 2; 42-51
0033-2372
Pojawia się w:
Przegląd Statystyczny
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-12 z 12

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