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Wyszukujesz frazę "convexity" wg kryterium: Temat


Tytuł:
Recognizing weighted directed cartesian graph bundles
Autorzy:
Zmazek, Blaz
Zerovnik, Janez
Powiązania:
https://bibliotekanauki.pl/articles/743682.pdf
Data publikacji:
2000
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
graph bundles
Cartesian graph product
weighted digraphs
half-convexity
Opis:
In this paper we show that methods for recognizing Cartesian graph bundles can be generalized to weighted digraphs. The main result is an algorithm which lists the sets of degenerate arcs for all representations of digraph as a weighted directed Cartesian graph bundle over simple base digraphs not containing transitive tournament on three vertices. Two main notions are used. The first one is the new relation $^→δ*$defined among the arcs of a digraph as a weighted directed analogue of the well-known relation δ*. The second one is the concept of half-convex subgraphs. A subgraph H is half-convex in G if any vertex x ∈ G∖H has at most one predecessor and at most one successor.
Źródło:
Discussiones Mathematicae Graph Theory; 2000, 20, 1; 39-56
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Construction of a k-immunization strategy with the highest convexity
Autorzy:
Zaremba, L.
Powiązania:
https://bibliotekanauki.pl/articles/206561.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
immunizacja
wypukłość
convexity
immunization
K-T conditions
unanticipated return
Opis:
Assuming that interest rate shocks are proportional to their values plus one, we prove in Theorem 1 the existence of and construct a portfolio Z[sup *] with the highest convexity in the class of portfolios that solve the immunization problem to meet the liability to pay C dollars K years from now. Z[sup *] appears to be a barbell strategy with two zero-coupon bonds with the shorest and the longest maturities. This intuitively clear result has been obtained here in a rigorous way by means of the K-T conditions. In addition, we show that our result is stricly related to the problem of maximization of the unanticipated rate of return on a portfolio solving the above immunization problem (Theorem 2). Two more results concerning the unanticipated return after K years are provided with proofs. An example illustrating the role of convexity in maximization of the unanticipated return is included. Despite the fact that there exists a pretty vast literature on bond portfolio strategies, the present paper offers a new methodological approach to this area (see Ingersoll, Skelton, Weil, 1978).
Źródło:
Control and Cybernetics; 1998, 27, 1; 135-144
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new reciprocal Rayleigh extension: properties, copulas, different methods of estimation and a modified right-censored test for validation
Autorzy:
Yousof, Haitham M.
Ali, M. Masoom
Goual, Hafida
Ibrahim, Mohamed
Powiązania:
https://bibliotekanauki.pl/articles/1827545.pdf
Data publikacji:
2021-09-06
Wydawca:
Główny Urząd Statystyczny
Tematy:
Xgamma model
reciprocal Rayleigh model
simulations
bootstrapping
Farlie Gumbel Morgenstern copula
least squares
Cramer-Von-Mises
Ali-Mikhail-Haq copula
convexity
concavi
Opis:
In this article, a new reciprocal Rayleigh extension called the Xgamma reciprocal Rayleigh model is defined and studied. The relevant statistical properties are derived, and the useful results related to the convexity and concavity are addressed. We discussed the estimation of the parameters using different estimation methods such as the maximum likelihood estimation method, the ordinary least squares estimation method, the weighted least squares estimation method, the Cramer-Von-Mises estimation method, and the bootstrapping method. A simulation study was conducted to assess the performances of the proposed estimation methods are investigated through a simulation study. Many bivariate and multivariate type model have also been derived based on Farlie-Gumbel-Morgenstern copula, the Clayton copula, Renyi's entropy copula and the Ali-Mikhail-Haq copula. A modified Nikulin-Rao-Robson test for right-censored validation is applied to a censored real data set.
Źródło:
Statistics in Transition new series; 2021, 22, 3; 99-121
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Second-order optimality conditions in nonsmooth vector optimization
Autorzy:
Yadav, Priyanka
Powiązania:
https://bibliotekanauki.pl/articles/31342762.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
vector optimization
cones
nonsmooth second-order cone-convexity
second-order optimality
duality
Opis:
In this paper, we introduce new classes of nonsmooth second-order cone-convex functions and respective generalizations in terms of first and second-order directional derivative. These classes encapsulate several already existing classes of cone-convex functions and their weaker variants. Second-order KKT type sufficient optimality conditions and duality results for a nonsmooth vector optimization problem are proved using these functions. The results have been supported by examples.
Źródło:
Control and Cybernetics; 2023, 52, 1; 35-51
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
J-convexity constants
Autorzy:
Wang, J.
Powiązania:
https://bibliotekanauki.pl/articles/255478.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
new quantitative index
J-convexity constants
n-th von Neumann-Jordan constants
Orlicz spaces
Opis:
We introduce the J-convexity constants on Banach spaces and give some properties of the constants. We give the relations between the J-convexity constants and the n-th von Neumann-Jordan constants. Using the quantitative indices we estimate the value of J-convexity constants in Orlicz spaces.
Źródło:
Opuscula Mathematica; 2007, 27, 1; 167-174
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generalized approximate midconvexity
Autorzy:
Tabor, J.
Powiązania:
https://bibliotekanauki.pl/articles/969650.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
approximately midconvex function
convexity
paraconvexity
semiconcavity
Opis:
Let X be a normed space and V ⊂ X a convex set with nonempty interior. Let α : [0, ∞) → [0, ∞) be a given nondecreasing function. A function ƒ : V → R is α(⋅)-midconvex if ƒ [wzór]. In this paper we study α(⋅)-midconvex functions. Using a version of Bernstein-Doetsch theorem we prove that if ƒ is α(⋅)-midconvex and locally bounded from above at every point then ƒ(rx + (1 - r)y) ≤ rƒ(x) + (1 - r)ƒ(y) + Pα(r, ¦¦x - y¦¦) for x,y ∈ V and r ∈ [0,1], where Pα : [0,1] x [0,∞) → [0,∞) is a specific function dependent on α. We obtain three different estimations of Pα. This enables us to generalize some results concerning paraconvex and semiconcave functions.
Źródło:
Control and Cybernetics; 2009, 38, 3; 655-669
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The generalized sine function and geometrical properties of normed spaces
Autorzy:
Szostok, T.
Powiązania:
https://bibliotekanauki.pl/articles/255087.pdf
Data publikacji:
2015
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
geometry of normed spaces
smoothness
strict convexity
Birkhoff-James orthogonality
conditional functional equations
Opis:
Let [formula] be a nornied space. We deal here with a function s : X x X —> R given by the formula [formula] (for x = 0 we must define it separately). Then we take two unit vectors x and y such that y is orthogonal to x in the Birkhoff-James sense. Using these vectors we construct new functions Φx,y which are defined on R. If X is an inner product space, then Φx, y = sin and, therefore, one may call this function a generalization of the sine function. We show that the properties of this function are connected with geometrical properties of the normed space X.
Źródło:
Opuscula Mathematica; 2015, 35, 1; 117-126
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Twice Differentiable Characterizations of Convexity Notions for Functions on Full Dimensional Convex Sets
Autorzy:
Stein, Oliver
Powiązania:
https://bibliotekanauki.pl/articles/1373546.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
convexity
strict convexity
strong convexity
true convexity
differentiable characterization
full dimensional convex set
Opis:
We derive $C^2$−characterizations for convex, strictly convex, as well as strongly convex functions on full dimensional convex sets. In the cases of convex and strongly convex functions this weakens the well-known openness assumption on the convex sets. We also show that, in a certain sense, the full dimensionality assumption cannot be weakened further. In the case of strictly convex functions we weaken the well-known sufficient $C^2$−condition for strict convexity to a characterization. Several examples illustrate the results.
Źródło:
Schedae Informaticae; 2012, 21; 55-63
0860-0295
2083-8476
Pojawia się w:
Schedae Informaticae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kuhn-Tucker type optimality conditions for some class of nonsmooth programming problems
Autorzy:
Śmietański, M. J.
Powiązania:
https://bibliotekanauki.pl/articles/206291.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
pochodna Diniego
pochodna Clarka
wypukłość uogólniona
liniowość uogólniona
warunki konieczne i wystarczające optymalności
nonsmooth programming
Dini derivative
Clarke derivative
generalized convexity
generalized linearity
necessary and sufficient optimality conditions
Opis:
We consider two nonlinear programming problems with nonsmooth functions. The necessary and sufficient first order optimality conditions use the Dini and Clarke derivatives. However, the obtained Kuhn-Tucker conditions have a rather classical form. The sufficient conditions alone are obtained thanks to some properties of generalized convexity and generalized linearity of functions. The necessary and sufficient optimality conditions are given in the Lagrange form.
Źródło:
Control and Cybernetics; 2003, 32, 2; 361-376
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the order of starlikeness and convexity of complex harmonic functions with a two-parameter coefficient condition
Autorzy:
Sibelska, Agnieszka
Powiązania:
https://bibliotekanauki.pl/articles/747178.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
Complex harmonic functions
analytic conditions
convexity of order \(\beta\)
starlikeness of order \(\beta\)
Opis:
The article of J. Clunie and T. Sheil-Small [3], published in 1984, intensified the investigations of complex functions harmonic in the unit disc \(\Delta\). In particular, many papers about some classes of complex mappings with the coefficient conditions have been published. Consideration of this type was undertaken in the period 1998–2004 by Y. Avci and E. Złotkiewicz [2], A. Ganczar [5], Z. J. Jakubowski, G. Adamczyk, A. Łazinska and A. Sibelska [1], [8], [7], H. Silverman [12] and J. M. Jahangiri [6], among others. This work continues the investigations described in [7]. Our results relate primarily to the order of starlikeness and convexity of functions of the aforementionedclasses.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica; 2010, 54, 1
0365-1029
2083-7402
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On invariant domains of holomorphy
Autorzy:
Sergeev, A.
Powiązania:
https://bibliotekanauki.pl/articles/1360090.pdf
Data publikacji:
1995
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
complexification
orbit connectedness
orbit convexity
extended future tube
matrix Reinhardt domains
Źródło:
Banach Center Publications; 1995, 31, 1; 349-357
0137-6934
Pojawia się w:
Banach Center Publications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some Convexity properties in Musielak-Orlicz sequence spaces endowed with the Luxemburg Norm
Autorzy:
Saejung, Satit
Powiązania:
https://bibliotekanauki.pl/articles/745280.pdf
Data publikacji:
2005
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
k-strict convexity
uniform convexity in every direction
property K
property H
and property G
Musielak-Orlicz sequence space
Opis:
Criteria for k-strict convexity, uniform convexity in every direction, property K, property H, and property G in Musielak-Orlicz sequence spaces and their subspaces endowed with the Luxemburg norm are presented. In particular, we obtain a characterization of such properties of Nakano sequence spaces.
Źródło:
Commentationes Mathematicae; 2005, 45, 1
0373-8299
Pojawia się w:
Commentationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Information-type divergence when the likelihood ratios are bounded
Autorzy:
Rukhin, Andrew
Powiązania:
https://bibliotekanauki.pl/articles/1339144.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
information measures
multiple decisions
convexity
likelihood ratio
Opis:
The so-called ϕ-divergence is an important characteristic describing "dissimilarity" of two probability distributions. Many traditional measures of separation used in mathematical statistics and information theory, some of which are mentioned in the note, correspond to particular choices of this divergence. An upper bound on a ϕ-divergence between two probability distributions is derived when the likelihood ratio is bounded. The usefulness of this sharp bound is illustrated by several examples of familiar ϕ-divergences. An extension of this inequality to ϕ-divergences between a finite number of probability distributions with pairwise bounded likelihood ratios is also given.
Źródło:
Applicationes Mathematicae; 1996-1997, 24, 4; 415-423
1233-7234
Pojawia się w:
Applicationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
(s,S)-type policy for a production inventory problem with limited backlogging and with stockouts
Autorzy:
Rempała, Ryszarda
Powiązania:
https://bibliotekanauki.pl/articles/1339233.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
(s,S)-policy
inventory
dynamic programming
limited backlogging
k-convexity
Opis:
A production inventory problem with limited backlogging and with stockouts is described in a discrete time, stochastic optimal control framework with finite horizon. It is proved by dynamic programming methods that an optimal policy is of (s,S)-type. This means that in every period the policy is completely determined by two fixed levels of the stochastic inventory process considered.
Źródło:
Applicationes Mathematicae; 1996-1997, 24, 3; 343-354
1233-7234
Pojawia się w:
Applicationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New estimate for the curvature of an order-convex set and related questions
Autorzy:
Ramazanov, Ali B.
Powiązania:
https://bibliotekanauki.pl/articles/2050043.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
gradient
estimates
curvature
convexity
algorithm
Opis:
It is well known that in discrete optimization problems, gradient (local) algorithms do not always guarantee an optimal solution. Therefore, the problem arises of finding the accuracy of the gradient algorithm. This is a fairly well-known problem and numerous publications have been devoted to it. In establishing accuracy, various approaches are used. One of these approaches is to obtain guaranteed estimates of the accuracy of the gradient algorithm in terms of the curvature of the admissible domain. With this approach, it is required to find the curvatures of the admissible region. Since finding the exact value of curvature is a difficult problem to solve, curvature estimates in terms of more or less simply calculated parameters of the problem are relevant. A new improved bound for the curvature of an order-convex set is found and is presented in this paper in terms of the steepness and parameters of strict convexity of the function.
Źródło:
Control and Cybernetics; 2020, 49, 2; 233-240
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł

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