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1
Content available remote Behaviour of global solutions for a system of reaction-diffusion equations from combustion theory
100%
Badraoui S.
Applicationes Mathematicae
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1999
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tom 26
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nr 2
133-150
EN
We are concerned with the boundedness and large time behaviour of the solution for a system of reaction-diffusion equations modelling complex consecutive reactions on a bounded domain under homogeneous Neumann boundary conditions. Using the techniques of E. Conway, D. Hoff and J. Smoller [3] we also show that the bounded solution converges to a constant function as t → ∞. Finally, we investigate the rate of this convergence.
2
Content available On the global attractivity and the periodic character of a recursive sequence
100%
Elsayed E. M.
Opuscula Mathematica
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2010
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tom Vol. 30, no. 4
431-446
EN
In this paper we investigate the global convergence result, boundedness, and periodicity of solutions of the recursive sequence [formula], where the parameters a, b, c, d and e are positive real numbers and the initial conditions x-2, x-1 and x0 are positive real numbers.
3
Content available remote Qualitative properties for a higher order rational difference equation
100%
Elabbasy E. M. , Eleissawy S. M.
Fasciculi Mathematici
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2013
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tom Nr 50
33--50
EN
The main objective of this paper is to study the behavior of solutions of the difference equation ...[wzór] where the initial conditions x-r, x-r+1,...,x0 are arbitrary positive real numbers, r = max{q, l,p} is nonnegative integer and a, b, c, d are positive constants. Also, we give the solution of some special cases of this equation.
4
Content available Stability criteria for a class of stochastic distributed delay systems
100%
Ficak B. , Klamka J.
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2013
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tom Vol. 61, nr 1
221-228
EN
In the paper linear distributed delay stochastic systems are considered. Using theory of stochastic differential equations sufficient conditions for different kinds of stability are formulated and proved. The article attempts to generalise results presented in the paper [1] and thus theorems proved in [1] become a special case of a generalised approach. The considered class is wider - the function that influence dynamics of a problem can be a real solution of N-degree linear deterministic differential equation. Therefore the generalised reduction technique of distributed delay to lumped delay has to be applied. Criteria for numerous properties of the aforementioned class followed Mao theory designed for point delay systems [2, 3].
5
Content available remote Boundedness and persistence of solutions of a nonlinear difference equation
88%
Stević S.
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2003
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tom Vol. 36, nr 1
99--104
EN
In this paper we obtain sufficient conditions for the boundedness as well ;is for the unboundedness of the positive solutions of the difference equation xn+1=f(xn,...,xn-k+1), n=0,1,2,...,where k is a positive integer and the initial conditions x-k+1, X-k+2,...x0 are arbitrary positive numbers.
6
Content available remote A Survey of Decidability Results for Elementary Object Systems
88%
Köhler-Bußmeier M.
Fundamenta Informaticae
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2014
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tom Vol. 130, nr 1
99--123
EN
This contribution presents recent results on Elementary Object Systems (EOS). Object nets are Petri nets which have Petri nets as tokens – an approach known as the nets-within-nets paradigm. In this work we study the relationship of EOS to existing Petri net formalisms. It turns out that EOS are equivalent to counter programs. But even for the restricted subclass of conservative EOS reachability and liveness are undecidable problems. On the other hand for other properties like boundedness are still decidable for conservative EOS. We also study the sub-class of generalised state machines, which is worth mentioning since it combines decidability of many theoretically interesting properties with a quite rich practical modelling expressiveness.
7
Content available remote On the solutions of a rational system of difference equations
75%
Elsayed E. M.
Fasciculi Mathematici
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2010
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tom Nr 45
25-36
EN
In this paper we deal with the solutions of the system of the difference equations xn+1 = ...[wzór], yn+1 = ...[wzór], with a nonzero real numbers initial conditions.
8
Content available remote Weighted composition operators from weighted hardy spaces to weighted-type spaces
75%
Zhu X.
Demonstratio Mathematica
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2013
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tom Vol. 46, nr 2
335--344
EN
The boundedness and compactness of the weighted composition operator from weighted Hardy spaces to weighted-type spaces are studied in this paper.
9
Adjoint of generalized Cesáro operators on analytic function spaces
75%
Naik S. , Nath P. K.
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2020
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tom Vol. 26, nr 2
185--192
EN
In this article, we define a convolution operator and study its boundedness on mixed-norm spaces. In particular,we obtain awell-known result on the boundedness of composition operators given by Avetisyan and Stević in [K. Avetisyan and S. Stević, The generalized Libera transform is bounded on the Besov mixednorm, BMOA and VMOA spaces on the unit disc, Appl. Math. Comput. 213 (2009), no. 2, 304-311]. Also we consider the adjoint Ab,c for b > 0 of two parameter families of Cesáro averaging operators and prove the boundedness on Besov mixed-norm spaces Bp,qα+(c−1) for c > 1.
10
Content available remote Patterns of boundedness of the rational system xn+1 = ...[wzór] and yn+1 = ...[wzór]
75%
Camouzis E. , Drymonis E. , Ladas G.
Fasciculi Mathematici
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2010
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tom Nr 44
9-18
EN
We establish the boundedness character of solutions of the rational system in the title, with the parameters α1, β1 positive and the remaining eight parameters nonnegative and with arbitrary nonnegative initial conditions such that the denominators are always positive. We present easily verifiable necessary and sufficient conditions, explicitly stated in terms of the parameters, which determine the boundedness character of the system.
11
Content available The composition operators between Morrey type spaces
75%
Xu J.
Science, Technology and Innovation
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2022
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tom Vol. 16, no. 3-4
50--56
EN
In this paper, we characterize the boundedness of composition operator Cφ from Morrey space H²K₁ to H²K₂ on the unit complex disk.
12
Content available remote Abundance, biomass and density boundaries in the Hymenoptera : analysis of the abundance - weight relationship and differences between forest and open landscape habitats
75%
Ulrich W.
Polish Journal of Ecology
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1999
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tom Vol. 47, no 1
73-86
EN
The density - weight distributions of the hymenopteran species in a beech forest on limestone and a dry meadow on limestone near Gottingen (FRG) were studied. Species and density distributions (logarithmic size classes) turned out to follow normal and log-normal distributions with the meadow having the more narrow shape. Upper weight classes accumulated more total biomass m^-2 than lower ones, resulting in a rejection of the equal biomass hypothesis in the case of the Hymenoptera. An analysis of the density - weight relationship revealed an upper density boundary for the hymenopteran species which can be defined by second order polynomial functions. Mean and upper densities of small hymenopteran species ranged well below their boundaries, with an asymptotic relationship between distance from the boundary and species weight. The area defined by the boundaries may mark the area of stability: exceeding the species specific boundary was always followed by a marked decline oreven a collapse of population density.
13
Content available Of ‘Bodies’ and Related Names in the History of English Semantics: Semantic Dynamics vs. Semantic Boundedness
75%
Dekeyser X.
Anglica. An International Journal of English Studies
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2015
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nr 24/2
63-78
EN
This paper deals with the names for both living and dead bodies, more particularly OE lic and lichama, OE bodig and finally ME corpse. The main focus will be on the contrast between semantic dynamics and boundedness, together with what we refer to as semantic redeployment. Body proves to be a very dynamic lexeme. In addition, it also contributed to the system of grammaticalized quantifier pronouns. This is in sharp contrast with the boundedness of lic and lichama, which gradually got lost in the course of ME. Initially, the loan lexeme corpse seemed to follow the semantic paradigm of body. However, in present-day English it has only preserved its prototypical meaning of dead body. Interestingly, my data suggest that words related to ‘death’ do not tend to give rise to any metonymical or metaphorical developments. The eventual result of these lexico-semantic changes is a far-reaching redeployment in Modern English in terms of a binary contrast between two lexical items: polysemous body, with a vast array of mostly metaphorical meanings, and monosemous corpse.
14
Content available remote Stability for certain fourth order nonlinear differential equations
63%
Lin S. , Liu Z. , Yu Y.
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1998
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tom Vol. 31, nr 1
87-96
15
Content available remote On the difference equation xn+1 = α + ...[wzór]
63%
Yalçinkaya ĺ.
|
|
tom Nr 42
133-139
EN
In this paper, we investigate the global behavior of the difference equation of order three xn+1 = α + ...[wzór], n = 0, 1,… where the parameters α, k ∈ (0, ∞) and the initial values x-2, x-1 and x0 are arbitrary positive real numbers.
16
Content available Bi-/multilingual Communication, Identity and the Posited Intermingling of Language Systems in the Mind
63%
Singleton D.
|
|
tom 5
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nr 2
25-38
EN
There seems to be a desire abroad in some areas of our field to abandon all talk of bounds between language-varieties in the mind. The response offered here to such a position is that language knowledge in the mind is all its aspects, in fact, highly differentiated, and that this differentiation broadly follows the lines recognized by the traditional conception which draws (always, of course, crossable) lines between languages. One powerful set of evidence in favour of this latter claim is that offered by phenomena observable in everyday bilingual and multilingual language use and interaction.  Such evidence bespeaks a necessary capacity on the part of multilinguals to keep their languages apart when using them, and an adeptness – even at a very early age – at making decisions as to which language to speak to whom.  The article explores such phenomena, which are heavy with consequences for the unboundedness view of languages. Another dimension of bilingual/multilingual experience which bespeaks boundedness is the way in which different languages connect to different identities or aspects of identity, which is also discussed in the article.
17
Content available remote Unconditionally positive NSFD and classical finite difference schemes for biofilm formation on medical implant using Allen-Cahn equation
63%
Tijani Y. O. , Appadu A. R.
Demonstratio Mathematica
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2022
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tom Vol. 55, nr 1
40--60
EN
The study of biofilm formation is becoming increasingly important. Microbes that produce biofilms have complicated impact on medical implants. In this paper, we construct an unconditionally positive non-standard finite difference scheme for a mathematical model of biofilm formation on a medical implant. The unknowns in many applications reflect values that cannot be negative, such as chemical component concentrations or population numbers. The model employed here uses the bistable Allen-Cahn partial differential equation, which is a generalization of Fisher’s equation. We study consistency and convergence of the scheme constructed. We compare the performance of our scheme with a classical finite difference scheme using four numerical experiments. The technique used in the construction of unconditionally positive method in this study can be applied to other areas of mathematical biology and sciences. The results here elaborate the benefits of the non-standard approximations over the classical approximations in practical applications.
18
Content available remote The concept of boundedness and the Bohr compactification of a MAP Abelian group
63%
Galindo J. , Hernández S.
Fundamenta Mathematicae
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1999
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tom 159
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nr 3
195-218
EN
Let G be a maximally almost periodic (MAP) Abelian group and let ℬ be a boundedness on G in the sense of Vilenkin. We study the relations between ℬ and the Bohr topology of G for some well known groups with boundedness (G,ℬ). As an application, we prove that the Bohr topology of a topological group which is topologically isomorphic to the direct product of a locally convex space and an $ℒ_∞$-group, contains "many" discrete C-embedded subsets which are C*-embedded in their Bohr compactification. This result generalizes an analogous theorem of van Douwen for the discrete case and some other ones due to Hartman and Ryll-Nardzewski concerning the existence of $I_0$-sets.  We also obtain some results on preservation of compactness for the Bohr topology of several types of MAP Abelian groups, like $ℒ_∞$-groups, locally convex vector spaces and free Abelian topological groups.
19
Content available remote Completeness Results for Generalized Communication-free Petri Nets with Arbitrary Arc Multiplicities
51%
Mayr E. W. , Weihmann J.
|
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tom Vol. 143, nr 3/4
355--391
EN
We investigate gcf-Petri nets, a generalization of communication-free Petri nets allowing arbitrary arc multiplicities, and characterized by the sole restriction that each transition has at most one incoming arc. We use canonical firing sequences with nice properties for gcf-PNs to show that the RecLFS, (zero-)reachability, covering, and boundedness problems of gcf-PNs are in PSPACE. By simulating PSPACE-Turing machines by gss-PNs, a subclass of gcf-PNs where additionally all transitions have at most one outgoing arc, we ultimately obtain PSPACE-completess for these problems in case of gss-PNs or gcf-PNs. Additionally, we prove PSPACE-completeness for the liveness problem of gcf-PNs. Last, we show PSPACE-hardness as well as a doubly exponential space upper bound for the containment and equivalence problems of gss-PNs or gcf-PNs.
20
Content available remote Existence and uniqueness of the weak solution for Keller-Segel model coupled with Boussinesq equations
51%
Slimani A. , Bouzettouta L. , Guesmia A.
|
|
tom Vol. 54, nr 1
558--575
EN
Keller-Segel chemotaxis model is described by a system of nonlinear partial differential equations: a convection diffusion equation for the cell density coupled with a reaction-diffusion equation for chemoattractant concentration. In this work, we study the phenomenon of Keller-Segel model coupled with Boussinesq equations. The main objective of this work is to study the global existence and uniqueness and boundedness of the weak solution for the problem, which is carried out by the Galerkin method.
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