Journal of Nonlinear Mathematical Physics

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902 articles
Research Article

On a graded q-differential algebra

Viktor ABRAMOV
Pages: 1 - 8
Given an associative unital ZN -graded algebra over the complex numbers we construct the graded q-differential algebra by means of a graded q-commutator, where q is a primitive N-th root of unity. The N-differential d of the graded q-differential algebra is a homogeneous endomorphism of degree 1 satisfying...
Research Article

A Note on Surface Profiles for Symmetric Gravity Waves with Vorticity

Mats EHRNSTROM
Pages: 1 - 8
We consider a nontrivial symmetric periodic gravity wave on a current with nondcreasing vorticity. It is shown that if the surface profile is monotone between trough and crest, it is in fact strictly monotone. The result is valid for both finite and infinite depth.
Research Article

Asymptotic behavior of discrete holomorphic maps zc and log(z)

Sergey I AGAFONOV
Pages: 1 - 14
It is shown that discrete analogs of zc and log(z), defined via particular "integrable" circle patterns, have the same asymptotic behavior as their smooth counterparts. These discrete maps are described in terms of special solutions of discrete Painlevé-II equations, asymptotics of these solutions providing...
Research Article

A Chorin-Type Formula for Solutions to a Closure Model for the von K´arm´an­Howarth Equation 1

V N GREBENEV, M OBERLACK
Pages: 1 - 9
The article is devoted to studying the Millionshtchikov closure model (a particular case of a model introduced by Oberlack [14]) for isotropic turbulence dynamics which appears in the context of the theory of the von K´arm´an-Howarth equation. We write the model in an abstract form that enables us to...
Research Article

On a "Quasi" Integrable Discrete Eckhaus Equation

M J ABLOWITZ, C D AHRENS
Pages: 1 - 12
In this paper, a discrete version of the Eckhaus equation is introduced. The discretiztion is obtained by considering a discrete analog of the transformation taking the cotinuous Eckhaus equation to the continuous linear, free Schrödinger equation. The resulting discrete Eckhaus equation is a nonlinear...
Review Article

So. . . what was the question?

Gérard G EMCH
Pages: 1 - 8
An overview of the lectures at the 2002 Bialowiea Workshop is presented. The symbol* after a proper name indicates that a copy of the corresponding contribution to the proceedings was communicated to the author of this summary.
Research Article

On the Quantization of Yet Another Two Nonlinear Harmonic Oscillators

Francesco CALOGERO
Pages: 1 - 6
In two previous papers the quantization was discussed of three one-degree-of-freedom Hamiltonians featuring a constant c, the value of which does not influence at all the corresponding classical dynamics (which is characterized by isochronous solutions, all of them periodic with period 2: "nonlinear...
Research Article

Comparisons Between Vector and Matrix Padé Approximants

Claude BREZINSKI
Pages: 1 - 12
In this paper, we compare the degrees and the orders of approximation of vector and matrix Padé approximants for series with matrix coefficients. It is shown that, in this respect, vector Padé approximants have better properties. Then, matrix­vector Padé approximants are defined and constructed. Finally,...
Research Article

Navier­Stokes Equations with Nonhomogeneous Dirichlet Data

Herbert AMANN
Pages: 1 - 11
We discuss the solvability of the time-dependent incompressible Navier­Stokes equtions with nonhomogeneous Dirichlet data in spaces of low regularity.
Research Article

Noncentral Extensions as Anomalies in Classical Dynamical Systems

Jorge E SOLOMIN, Marcela ZUCCALLI
Pages: 1 - 9
A two cocycle is associated to any action of a Lie group on a symplectic manifold. This allows to enlarge the concept of anomaly in classical dynamical systems considered by F Toppan in [J. Nonlinear Math. Phys. 8, Nr. 3 (2001), 518­533] so as to encompass some extensions of Lie algebras related to noncanonical...
Research Article

Hidden Symmetries, First Integralsvand Reduction of Order of Nonlinear Ordinary Differential Equations

Barbara ABRAHAM-SHRAUNER
Pages: 1 - 9
The reduction of nonlinear ordinary differential equations by a combination of first integrals and Lie group symmetries is investigated. The retention, loss or even gain in symmetries in the integration of a nonlinear ordinary differential equation to a first integral are studied for several examples....
Research Article

From Bi-Hamiltonian Geometry to Separation of Variables: Stationary Harry-Dym and the KdV Dressing Chain

Maciej BLASZAK
Pages: 1 - 13
Separability theory of one-Casimir Poisson pencils, written down in arbitrary coordnates, is presented. Separation of variables for stationary Harry-Dym and the KdV dressing chain illustrates the theory.
Research Article

Kovalevski Exponents and Integrability Properties in Class A Homogeneous Cosmological Models

Marek SZYDLOWSKI, Marek BIESIADA
Pages: 1 - 10
Qualitative approach to homogeneous anisotropic Bianchi class A models in terms of dynamical systems reveals a hierarchy of invariant manifolds. By calculating the Kovalevski Exponents according to Adler - van Moerbecke method we discuss how algebraic integrability property is distributed in this class...
Research Article

Complex Angle Variables for Constrained Integrable Hamiltonian Systems

S ABENDA, Yu FEDOROV
Pages: 1 - 4
We propose Dirac formalism for constraint Hamiltonian systems as an useful tool for the algebro-geometrical and dynamical characterizations of a class of integrable systems, the so called hyperelliptically separable systems. As a model example, we apply it to the classical geodesic flow on an ellipsoid.
Research Article

UV Manifold and Integrable Systems in Spaces of Arbitrary Dimension

A N LEZNOV
Pages: 1 - 7
The 2n dimensional manifold with two mutually commutative operators of differetiation is introduced. Nontrivial multidimensional integrable systems connected with arbitrary graded (semisimple) algebras are constructed. The general solution of them is presented in explicit form.
Research Article

Lax Pairs, Painlevé Properties and Exact Solutions of the Calogero Korteweg-de Vries Equation and a New (2 + 1)-Dimensional Equation

Song-Ju YU, Kouichi TODA
Pages: 1 - 13
We prove the existence of a Lax pair for the Calogero Korteweg-de Vries (CKdV) equation. Moreover, we modify the T operator in the the Lax pair of the CKdV equation, in the search of a (2 + 1)-dimensional case and thereby propose a new equation in (2+1) dimensions. We named this the (2+1)-dimensional...
Research Article

Solutions of WDVV Equations in Seiberg-Witten Theory from Root Systems

R. MARTINI, P.K.H. GRAGERT
Pages: 1 - 4
We present a complete proof that solutions of the WDVV equations in Seiberg-Witten theory may be constructed from root systems. A generalization to weight systems is proposed.
Research Article

On the Moyal Quantized BKP Type Hierarchies

Dolan Chapa SEN, A. Roy CHOWDHURY
Pages: 1 - 7
Quantization of BKP type equations are done through the Moyal bracket and the formalism of pseudo-differential operators. It is shown that a variant of the dressing operator can also be constructed for such quantized systems.
Research Article

Integrability of the Perturbed KdV Equation for Convecting Fluids: Symmetry Analysis and Solutions

J.M. CERVER´O, O. Zurr'on
Pages: 1 - 23
As an example of how to deal with nonintegrable systems, the nonlinear partial differential equation which describes the evolution of long surface waves in a convecting fluid ut + (uxxx + 6uux) + 5uux + (uxxx + 6uux)x = 0, is fully analyzed, including symmetries (nonclassical and contact transformatons),...
Research Article

Particle trajectories in linear periodic capillary and capillary-gravity deep-water waves

David HENRY
Pages: 1 - 7
We show that within the framework of linear theory the particle paths in a periodic gravity-capillary or pure capillary deep-water wave are not closed.
Research Article

Harmonic maps between quaternionic Kahler manifolds

S. Ianus, R. Mazzocco, G.E. Vilcu
Pages: 1 - 8
Research Article

Algebraic Discretization of the Camassa-Holm and Hunter-Saxton Equations

Rossen I Ivanov
Pages: 1 - 12
The Camassa-Holm (CH) and Hunter-Saxton (HS) equations have an interpretation as geodesic flow equations on the group of diffeomorphisms, preserving the H 1 and H 1 right-invariant metrics correspondingly. There is an analogy to the Euler equations in hydrodynamics, which describe geodesic flow for a...
Research Article

Nonlocal Extensions of Similarity Methods

George Bluman
Pages: 1 - 24
Similarity methods include the calculation and use of symmetries and conservation laws for a given partial differential equation (PDE). There exists a variety of software to calculate and use local symmetries and local conservation laws. However, it is often the case that a given PDE admits no useful...
Research Article

Quantum Integrability of the Dynamics on a Group Manifold

V Aldaya, M Calixto, J Guerrero, F F Lopez-Ruiz
Pages: 1 - 12
We study the dynamics of a particle moving on the SU(2) group manifold. An exact quantization of this system is accomplished by finding the unitary and irreducible representations of a finite-dimensional Lie subalgebra of the whole Poisson algebra in phase space. In fact, the basic position and momentum...
Research Article

Non-linear Schrödinger Equations, Separation and Symmetry

George SVETLICHNY
Pages: 2 - 26
We investigate the symmetry properties of hierarchies of non-linear Schrödinger equations, introduced in [2], which describe non-interacting systems in which tensor product wave-functions evolve by independent evolution of the factors (the separation property). We show that there are obstructions to...
Research Article

Taming Spatiotemporal Chaos by Impurities in the Parametrically Driven Damped Nonlinear Schrödinger Equation

N V ALEXEEVA, I V BARASHENKOV, G P TSIRONIS
Pages: 5 - 12
Solitons of the parametrically driven, damped nonlinear Schrödinger equation become unstable and seed spatiotemporal chaos for sufficiently large driving amplitudes. We show that the chaos can be suppressed by introducing localized inhomogeneities in the parameters of the equation. The pinning of the...
Research Article

Neumann and Bargmann Systems Associated with an Extension of the Coupled KdV Hierarchy

Zhimin JIANG
Pages: 5 - 12
An eigenvalue problem with a reference function and the corresponding hierarchy of nonlinear evolution equations are proposed. The bi-Hamiltonian structure of the hierarchy is established by using the trace identity. The isospectral problem is nonlinearized as to be finite-dimensional completely integrable...
Research Article

Gauge Transformations for a Family of Nonlinear Schrödinger Equations

Gerald A. GOLDIN
Pages: 6 - 11
An enlarged gauge group acts nonlinearly on the class of nonlinear Schrödinger equations introduced by the author in joint work with Doebner. Here the equations and the group action are displayed in the presence of an external electromagnetic field. All the gauge-invariants are listed for the coupled...
Research Article

µ-Holomorphic Projective Connections and Conformal Covariance

Mohamed KACHKACHI
Pages: 7 - 12
At the quantum level of a bidimensional conformal model, the conformal symmtry is broken by the diffeomorphism anomaly and the conformal covariance is not maintained. Here we interpret geometrically this conformal covariance as an exact holomorphy condition on a two-dimensional Riemann surface on which...
Research Article

Correctors for Some Nonlinear Monotone Operators

Johan BYSTRÖM
Pages: 8 - 30
In this paper we study homogenization of quasi-linear partial differential equations of the form -div (a (x, x/h, Duh)) = fh on with Dirichlet boundary conditions. Here the sequence (h) tends to 0 as h and the map a (x, y, ) is periodic in y, monotone in and satisfies suitable continuity conditions....
Research Article

Classical and Nonclassical Symmetries of a Generalized Boussinesq Equation

M.L. GANDARIAS, M.S. BRUZON
Pages: 8 - 12
We apply the Lie-group formalism and the nonclassical method due to Bluman and Cole to deduce symmetries of the generalized Boussinesq equation, which has the classical Boussinesq equation as an special case. We study the class of functions f(u) for which this equation admit either the classical or the...
Research Article

An invariant p-adic q-integral associated with q-Euler numbers and polynomials

Ismail Naci CANGÜL, Veli KURT, Yilmaz SIMSEK, Hong Kyung PAK, Seog-Hoon RIM
Pages: 8 - 14
The purpose of this paper is to consider q-Euler numbers and polynomials which are q-extensions of ordinary Euler numbers and polynomials by the computations of the p-adic q-integrals due to T. Kim, cf. [1, 3, 6, 12], and to derive the "complete sums for q-Euler polynomials" which are evaluated by using...
Research Article

Geometric approach to BRST-symmetry and ZN-generalization of superconnection

V ABRAMOV, O LIIVAPUU
Pages: 9 - 20
We propose a geometric approach to the BRST-symmetries of the Lagrangian of a topological quantum field theory on a four dimensional manifold based on the formalism of superconnections. Making use of a graded q-differential algebra, where q is a primitive N-th root of unity, we also propose a notion...
Research Article

A Note on q-Bernoulli Numbers and Polynomials

A S HEGAZI, M MANSOUR
Pages: 9 - 18
In this paper, we define a new q-analogy of the Bernoulli polynomials and the Bernoulli numbers and we deduced some important relations of them. Also, we dduced a q-analogy of the Euler-Maclaurin formulas. Finally, we present a relation between the q-gamma function and the q-Bernoulli polynomials.
Research Article

Regularization and Renormalization of Quantum Field Theories on Noncommutative Spaces

Harald GROSSE, Raimar WULKENHAAR
Pages: 9 - 20
We first review regularization methods based on matrix geometry which provide an ultraviolet cut-off for scalar fields respecting the symmetries. Sections of bundles over the sphere can be quantized, too. This procedure even allows to regularize supesymmetry without violating it. Recently, this work...
Research Article

Noetherian first integrals

PGL LEACH, GP FLESSAS
Pages: 9 - 21
From time to time one finds claims in the literature that first integrals/invariants of Lagrangian systems are nonnoetherian. Such claims diminish the contribution of Noether in the topic of integrability. We provide an explicit demonstration of noethe- rian symmetries associated with the integrals which...
Short Communication

A Note on the Degasperis-Procesi Equation

Octavian G MUSTAFA
Pages: 10 - 14
We prove that smooth solutions of the Degasperis-Procesi equation have infinite proagation speed: they loose instantly the property of having compact support.
Research Article

On the Cauchy Problem for a Nonlinearly Dispersive Wave Equation

Zhaoyang YIN
Pages: 10 - 15
We establish the local well-posedness for a new nonlinearly dispersive wave equation and we show that the equation has solutions that exist for indefinite times as well as solutions which blowup in finite time. Furthermore, we derive an explosion criterion for the equation and we give a sharp estimate...
Research Article

The Economy of Complete Symmetry Groups for Linear Higher Dimensional Systems

K ANDRIOPOULOS, P G L LEACH
Pages: 10 - 23
The complete symmetry groups of systems of linear second order ordinary differential equations are considered in the context of the simple harmonic oscillator. One finds that in general the representation of the complete symmetry group is not unique and in the particular case of a four-dimensional system...
Research Article

The Matrix Kadomtsev­Petviashvili Equation as a Source of Integrable Nonlinear Equations

Attilio MACCARI
Pages: 11 - 20
A new integrable class of Davey­Stewartson type systems of nonlinear partial diffrential equations (NPDEs) in 2+1 dimensions is derived from the matrix Kadomtsev­ Petviashvili equation by means of an asymptotically exact nonlinear reduction method based on Fourier expansion and spatio-temporal rescaling....
Research Article

The Cauchy Problem for the Nonlinear Schrödinger Equation on a Compact Manifold

Nicolas BURQ, Patrick GÉRARD, Nikolay TZVETKOV
Pages: 12 - 27
We discuss the wellposedness theory of the Cauchy problem for the nonlinear Schrödinger equation on compact Riemannian manifolds. New dispersive estimates on the linear Schrödinger group are used to get global existence in the energy space on arbirary surfaces and three-dimensional manifolds, generalizing...
Research Article

Proper-Time Relativistic Dynamics and the Fushchych-Shtelen Transformation

Tepper L. GILL, James LINDESAY, M.F. MAHMOOD, W.W. ZACHARY
Pages: 12 - 27
We report on a new formulation of classical relativistic Hamiltonian mechanics which is based on a proper-time implementation of special relativity using a transformation from observer proper-time, which is not invariant, to system proper-time which is a canonical contact transformation on extended phase-space....
Research Article

Some Symmetry Classifications of Hyperbolic Vector Evolution Equations

Stephen C ANCO, Thomas WOLF
Pages: 13 - 31
Motivated by recent work on integrable flows of curves and 1+1 dimensional sigma models, several O(N)-invariant classes of hyperbolic equations Utx = f(U, Ut, Ux) for an N-component vector U(t, x) are considered. In each class we find all scalinhomogeneous equations admitting a higher symmetry of least...
Research Article

Reduction of Order for Systems of Ordinary Differential Equations

C WAFO SOH, F M MAHOMED
Pages: 13 - 20
The classical reduction of order for scalar ordinary differential equations (ODEs) fails for a system of ODEs. We prove a constructive result for the reduction of order for a system of ODEs that admits a solvable Lie algebra of point symmetries. Applications are given for the case of a system of two...
Research Article

Hierarchies of Difference Equations and Bäcklund Transformations

Peter A CLARKSON, Andrew N W HONE, Nalini JOSHI
Pages: 13 - 26
In this paper we present a method for deriving infinite sequences of difference equations containing well known discrete Painlevé equations by using the Bäcklund transformtions for the equations in the second Painlevé equation hierarchy.
Research Article

Nonlinear Models in Quantum Optics through Quantum Algebras

Angel BALLESTEROS, Sergey CHUMAKOV
Pages: 13 - 17
The suq(2) algebra is shown to provide a natural dynamical algebra for some nonlnear models in Quantum Optics. Applications to the computation of eigenvalues and eigenvectors for the Hamiltonian describing second harmonics generation are proposed.
Research Article

On the Fourth-Order Accurate Compact ADI Scheme for Solving the Unsteady Nonlinear Coupled Burgers' Equations

Samir F. RADWAN
Pages: 13 - 34
The two-dimensional unsteady coupled Burgers' equations with moderate to severe gradients, are solved numerically using higher-order accurate finite difference schemes; namely the fourth-order accurate compact ADI scheme, and the fourth-order accurate Du Fort Frankel scheme. The question of numerical...
Research Article

Symmetry of the Schrödinger Equation with Variable Potential

Wilhelm FUSHCHYCH, Zoya SYMENOH
Pages: 13 - 22
We study symmetry properties of the Schrödinger equation with the potential as a new dependent variable, i.e., the transformations which do not change the form of the class of equations. We also consider systems of the Schrödinger equations with certain conditions on the potential. In addition we investigate...
Research Article

Particle Trajectories in Linearized Irrotational Shallow Water Flows

Delia Ionesco-Kruse
Pages: 13 - 27
We investigate the particle trajectories in an irrotational shallow water flow over a flat bed as periodic waves propagate on the water’s free surface. Within the linear water wave theory, we show that there are no closed orbits for the water particles beneath the irrotational shallow water waves. Depending...
Research Article

Existence of Periodic Solutions of a Type of Nonlinear Impulsive Delay Differential Equations with a Small Parameter

Jehad O Alzabut
Pages: 13 - 21
The Banach fixed point theorem is used to prove the existence of a unique( w) periodic solution of a new type of nonlinear impulsive delay differential equation with a small parameter.
Research Article

A Truncation for Obtaining all the First Degree Birational Transformations of the Painlevé Transcendents

Robert CONTE, Micheline MUSETTE
Pages: 14 - 28
A birational transformation is one which leaves invariant an ordinary differential eqution, only changing its parameters. We first recall the consistent truncation which has allowed us to obtain the first degree birational transformation of Okamoto for the mater Painlevé equation P6. Then we improve...
Research Article

Links Between Different Analytic Descriptions of Constant Mean Curvature Surfaces

E.V. FERAPONTOV, A.M. GRUNDLAND
Pages: 14 - 21
Transformations between different analytic descriptions of constant mean curvature (CMC) surfaces are established. In particular, it is demonstrated that the system
Research Article

A novel approach to the theory of Padé approximants

Christopher ATHORNE
Pages: 15 - 27
By associating polynomials and power series expansions with sln(C) modules we dscribe the theory of Padé approximants in terms of tensor products of representations and interpret their recurrence relations algebraically. The treatment links with the theory of Hirota derivatives and discrete integrable...
Research Article

Generalised Symmetries and the Ermakov-Lewis Invariant

R GOODALL, P G L LEACH
Pages: 15 - 26
Generalised symmetries and point symmetries coincide for systems of first-order odinary differential equations and are infinite in number. Systems of linear first-order ordinary differential equations possess a generalised rescaling symmetry. For the sytem of first-order ordinary differential equations...
Research Article

q-Euler numbers and polynomials associated with p-adic q-integrals

Taekyun KIM
Pages: 15 - 27
The main purpose of this paper is to present a systemic study of some families of multiple q-Euler numbers and polynomials. In particular, by using the q-Volkenborn integration on Zp, we construct p-adic q-Euler numbers and polynomials of higher order. We also define new generating functions of multiple...
Review Article

A Heat Transfer with a Source: the Complete Set of Invariant Difference Schemes

Vladimir DORODNITSYN, Roman KOZLOV
Pages: 16 - 50
In this letter we present the set of invariant difference equations and meshes which preserve the Lie group symmetries of the equation ut = (K(u)ux)x +Q(u). All special cases of K(u) and Q(u) that extend the symmetry group admitted by the differential equation are considered. This paper completes the...
Research Article

Two-Photon Algebra and Integrable Hamiltonian Systems

Angel BALLESTEROS, Francisco J HERRANZ
Pages: 18 - 22
The two-photon algebra h6 is used to define an infinite class of N-particle Hamiltonian systems having (N -2) additional constants of the motion in involution. By constrution, all these systems are h6-coalgebra invariant. As a straightforward application, a new family of (quasi)integrable N-dimensional...
Research Article

Deforming the Lie Superalgebra of Contact Vector Fields on S1|1 Inside the Lie Superalgebra of Superpseudodifferential Operators on S1|1

N BEN FRAJ, S OMRI
Pages: 19 - 33
We classify nontrivial deformations of the standard embedding of the Lie superalgebra K(1) of contact vector fields on the (1,1)-dimensional supercircle into the Lie supealgebra of superpseudodifferential operators on the supercircle. This approach leads to the deformations of the central charge induced...
Research Article

Non-coordinate case of graded differential algebra with ternary differential

Nadezda BAZUNOVA
Pages: 21 - 26
In this article, we generalize a construction of graded q-differential algebra with ternary differential satisfying the property d3 = 0 and q-Leibniz rule on the non-coordinate case, that is on the case where the differentials of generators of underlying algebra do not coincide with generators of bimodule...
Research Article

The Heun Equation and the Calogero-Moser-Sutherland System III: The Finite-Gap Property and the Monodromy

Kouichi TAKEMURA
Pages: 21 - 46
A new approach to the finite-gap property for the Heun equation is constructed. The relationship between the finite-dimensional invariant space and the spectral curve is clarified. The monodromies are calculated and are expressed as hyperelliptic integrals. Applications to the spectral problem for the...
Research Article

On Integrability of Differential Constraints Arising from the Singularity Analysis

S Yu SAKOVICH
Pages: 21 - 25
Integrability of differential constraints arising from the singularity analysis of two (1+1)-dimensional second-order evolution equations is studied. Two nonlinear ordnary differential equations are obtained in this way, which are integrable by quadrtures in spite of very complicated branching of their...
Research Article

On the Calculation of Finite-Gap Solutions of the KdV Equation

A.M. KOROSTIL
Pages: 22 - 33
A simple and general approach for calculating the elliptic finite-gap solutions of the Korteweg-de Vries (KdV) equation is proposed. Our approach is based on the use of the finite-gap equations and the general representation of these solutions in the form of rational functions of the elliptic Weierstrass...
Research Article

Singularity Analysis and Integrability of a Simplified Multistrain Model for the Transmission of Tuberculosis and Dengue Fever

MC Nucci, P.G.L. Leach
Pages: 22 - 34
We apply singularity analysis to a caricature of the simplified multistrain model of Castillo-Chavez and Feng (J Math Biol 35 (1997) 629–656) for the transmission of tuberculosis and the coupled two-stream vector-based model of Feng and Velasco- Hern ?andez (J Math Biol 35 (1997) 523–544) to identify...
Research Article

Boundary Algebra and Exact Solvability of the Asymmetric Exclusion Process

Boyka Aneva
Pages: 22 - 33
We consider a lattice driven diffusive system withUq(su(2)) invariance in the bulk. Within the matrix product states approach the stationary probability distribution is expressed as a matrix product state with respect to a quadratic algebra. Boundary processes amount to the appearance of parameter dependent...
Research Article

Peakon-Antipeakon Interaction

R BEALS, D H SATTINGER, J SZMIGIELSKI
Pages: 23 - 27
Explicit formulas are given for the multi-peakon-antipeakon solutions of the Camassa­ Holm equation, and a detailed analysis is made of both short-term and long-term aspects of the interaction between a single peakon and single anti-peakon.
Research Article

Stochastic Cohomology of the Frame Bundle of the Loop Space

R. LÉANDRE
Pages: 23 - 40
We study the differential forms over the frame bundle of the based loop space. They are stochastics in the sense that we put over this frame bundle a probability measure. In order to understand the curvatures phenomena which appear when we look at the Lie bracket of two horizontal vector fields, we impose...
Research Article

Four Dimensional Lie Symmetry Algebras and Fourth Order Ordinary Differential Equations

T CERQUETELLI, N CICCOLI, M C NUCCI
Pages: 24 - 35
Realizations of four dimensional Lie algebras as vector fields in the plane are explcitly constructed. Fourth order ordinary differential equations which admit such Lie symmetry algebras are derived. The route to their integration is described.
Research Article

Lie Symmetries, Infinite-Dimensional Lie Algebras and Similarity Reductions of Certain (2+1)-Dimensional Nonlinear Evolution Equations

M. LAKSHMANAN, M. SENTHIL VELAN
Pages: 24 - 39
The Lie point symmetries associated with a number of (2 + 1)-dimensional generalizations of soliton equations are investigated. These include the Niznik ­ Novikov ­ Veselov equation and the breaking soliton equation, which are symmetric and asymmetric generalizations respectively of the KDV equation,...
Research Article

Complex Lie Symmetries for Variational Problems

Sajid Ali, Fazal M Mahomed, Asghar Qadir
Pages: 25 - 35
We present the use of complex Lie symmetries in variational problems by defining a complex Lagrangian and considering its Euler-Lagrange ordinary differential equation. This Lagrangian results in two real “Lagrangians” for the corresponding system of partial differential equations, which satisfy Euler-Lagrange...
Research Article

Hierarchy of Chaotic Maps with an Invariant Measure and their Compositions

M A JAFARIZADEH, S BEHNIA
Pages: 26 - 41
We give a hierarchy of many-parameter families of maps of the interval [0, 1] with an invariant measure and using the measure, we calculate Kolmogorov­Sinai entropy of these maps analytically. In contrary to the usual one-dimensional maps these maps do not possess period doubling or period-n-tupling...
Research Article

On the matrix 3 × 3 exact solvable models of the type G2

C. BURDIK, S. POSTA, O NAVRATIL
Pages: 27 - 36
We study the exact solvable 3 × 3 matrix model of the type G2. We apply the construction similar to that one, which give the 2 × 2 matrix model. But in the studied case the construction does not give symmetric matrix potential. We conceive that the exact solvable 3 × 3 matrix potential model of the type...
Short Communication

Uniqueness of Steady Symmetric Deep-Water Waves with Vorticity

Mats EHRNSTRÖM
Pages: 27 - 30
Given a steady and symmetric deep-water wave we prove that the surface profile and the vorticity distribution determine the wave motion completely throughout the fluid.
Research Article

A New Discrete Hénon-Heiles System

Alan K COMMON, Andrew N W HONE, Micheline MUSETTE
Pages: 27 - 40
By considering the Darboux transformation for the third order Lax operator of the Sawada-Kotera hierarchy, we obtain a discrete third order linear equation as well as a discrete analogue of the Gambier 5 equation. As an application of this result, we consider the stationary reduction of the fifth order...
Research Article

A Hopf C-algebra associated with an action of SUq(1,1) on a two-parameter quantum deformation of the unit disc

Yury CHAPOVSKY
Pages: 27 - 45
We define a Hopf C -algebra associated with an action of the quantum group SUq(1, 1) on a two-parameter quantum deformation of the unit disc, which has a left comodule structure over this Hopf C -algebra. Mathematics Subject Classification (1991). 81C05.
Research Article

Integrable 1D Toda cellular automata

Mariusz BIALECKI
Pages: 28 - 35
First, we recall the algebro-geometric method of construction of finite field valued solutions of the discrete KP equation, and next we perform a reduction of dKP to the discrete 1D Toda equation.
Research Article

The Intermediate Surface Diffusion Flow on Spheres

Joachim ESCHER
Pages: 28 - 46
It is shown that solutions to the intermediate surface diffusion flow are real analytic in space and time, provided the initial surface is real diffeomorphic to a Euclidean sphere.
Research Article

Response Functions of Spiral Wave Solutions of the Complex Ginzburg­Landau Equation

I V BIKTASHEVA, V N BIKTASHEV
Pages: 28 - 34
Dynamics of spiral waves in perturbed two-dimensional autowave media can be dscribed asymptotically in terms of Aristotelean dynamics. We apply this general thory to the spiral waves in the Complex Ginzburg­Landau equation (CGLE). The RFs are found numerically. In this work, we study the dependence of...
Research Article

Symmetries of Separating Nonlinear Schrödinger Equations

George SVETLICHNY
Pages: 28 - 35
We review here the main properties of symmetries of separating hierarchies of nonlinear Schrödinger equations and discuss the obstruction to symmetry liftings from (n)particles to a higher number. We argue that for particles with internal degrees of freedom, new multiparticle effects must appear at each...
Research Article

The Initial-Boundary Value Poblem for the Korteweg-de Vries Equation on the Positive Quarter-Plane

Pham Loi VU
Pages: 28 - 43
The paper deals with a problem of developing an inverse-scattering transform for solving the initial-boundary value problem (IBVP) for the Korteweg-de Vries equation on the positive quarter-plane: pt - 6ppx + pxxx = 0, x 0, t 0, (a) with the given initial and boundary conditions: p(x, 0) = p(x), p(x)...
Research Article

Blow-Up Phenomena and Decay for the Periodic Degasperis-Procesi Equation with Weak Dissipation

Shuyin Wu, Zhaoyang Yin
Pages: 28 - 49
In the paper, several problems on the periodic Degasperis-Procesi equation with weak dissipation are investigated. At first, the local well-posedness of the equation is established by Kato’s theorem and a precise blow-up scenario of the solutions is given. Then, several critera guaranteeing the blow-up...
Research Article

Bäcklund Transformations on Coadjoint Orbits of the Loop Algebra ~gl(r)

Yuri FEDOROV
Pages: 29 - 46
There is a wide class of integrable Hamiltonian systems on finite-dimensional coadjoint orbits of the loop algebra ~gl(r) which are represented by r × r Lax equations with a rational spectral parameter. A reduced complex phase space is foliated with open subsets of Jacobians of regularized spectral curves....
Research Article

Existence of Dual Equations by Means of Strong Necessary Conditions - Analysis of Integrability of Partial Differential Nonlinear Equations

K SOKALSKI, T WIETECHA, D SOKALSKA
Pages: 31 - 52
A concept of strong necessary conditions for extremum of functional has been aplied for analysis an existence of dual equations for a system of two nonlinear Partial Differential Equations (PDE) in 1+1 dimensions. We consider two types of the dual equations: the Bäcklund transformations and the Bogomolny...
Research Article

On Bilinear Invariant Differential Operators Acting on Tensor Fields on the Symplectic Manifold

Pavel GROZMAN
Pages: 31 - 37
Let M be an n-dimensional manifold, V the space of a representation : GL(n)GL(V ). Locally, let T(V ) be the space of sections of the tensor bundle with fiber V over a sufficiently small open set U M, in other words, T(V ) is the space of tensor fields of type V on M on which the group Diff(M) of diffeomorphisms...
Research Article

Some Group Theoretical Aspects of Nonlinear Quantal Oscillators

K ANDRIOPOULOS, P G L LEACH
Pages: 32 - 42
We investigate the algebraic properties of the time-dependent Schrödinger equations of certain nonlinear oscillators introduced by Calogero and Graffi (Calogero F & Graffi S, On the quantisation of a nonlinear Hamiltonian oscillator Physics Letters A 313 (2003) 356-362; Calogero F, On the quantisation...
Research Article

On the Structure of the Bäcklund Transformations for the Relativistic Lattices

Vsevolod E. ADLER
Pages: 34 - 56
The Bäcklund transformations for the relativistic lattices of the Toda type and their discrete analogues can be obtained as the composition of two duality transformations. The condition of invariance under this composition allows to distinguish effectively the integrable cases. Iterations of the Bäcklund...
Research Article

Solutions of Adler's Lattice Equation Associated with 2-Cycles of the Bäcklund Transformation

James Atkinson, Frank Nijhoff
Pages: 34 - 42
The Bäcklund transformation (BT) of Adler's lattice equation is inherent in the equation itself by virtue of its multidimensional consistency. We refer to a solution of the equation that is related to itself by the composition of two BTs (with different Bäcklund parameters) as a 2-cycle of the BT. In...
Research Article

Threshold Behavior for Nonlinear Wave Equations

Piotr BIZON
Pages: 35 - 41
In this brief contribution, which is based on my talk at the conference, I discuss the dynamics of solutions of nonlinear wave equations near the threshold of singularity formation. The heuristic picture of threshold behavior is first presented in a general setting and then illustrated with three examples.
Research Article

Variational Methods for Solving Nonlinear Boundary Problems of Statics of Hyper-Elastic Membranes

V.A. TROTSENKO
Pages: 35 - 50
A number of important results of studying large deformations of hyper-elastic shells are obtained using discrete methods of mathematical physics [1]­[6]. In the present paper, using the variational method for solving nonlinear boundary problems of statics of hyper-elastic membranes under the regular...
Research Article

Conservations laws for critical Kohn-Laplace equations on the Heisenberg group

Yuri Dimitrov BOZHKOV, Igor Leite FREIRE
Pages: 35 - 47
Using the complete group classification of semilinear differential equations on the three-dimensional Heisenberg group H, carried out in a preceding work, we estab- lish the conservation laws for the critical Kohn-Laplace equations via the Noether’s Theorem.
Research Article

Second Order Dynamic Inclusions

Martin BOHNER, Christopher C TISDELL
Pages: 36 - 45
The theory of dynamic inclusions on a time scale is introduced, hence accommodating the special cases of differential inclusions and difference inclusions. Fixed point theory for set-valued upper semicontinuous maps, Green's functions, and upper and lower solutions are used to establish existence results...
Research Article

Singularity Analysis and a Function Unifying

the Painlevé, the Psi Series
Pages: 36 - 48
The classical (ARS) algorithm used in the Painlevé test picks up only those functions analytic in the complex plane. We complement it with an iterative algorithm giving the leading order and the next terms in all cases. This algorithm works both for an ascending series (about a singularity at finite...
Research Article

On the Self-Similar Solutions of Generalized Hydrodynamics Equations and Nonlinear Wave Patterns

V.A. DANYLENKO, V.A. VLADIMIROV
Pages: 36 - 43
Solutions of the system of dynamical equations of state and equations of the balance of mass and momentum are studied. The system possesses families of periodic, quasiperiodic and soliton-like invariant solutions. Self-similar solutions of this generalized hydrodynamic system are studied. Various complicated...
Research Article

Symmetries and Differential Forms

A. H. Davison, A. H. Kara
Pages: 36 - 43
The method for writing a differential equation or system of differential equations in terms of differential forms and finding their symmetries was devised by Harrison and Estabrook (1971). A modification to the method is demonstrated on a wave equation with variable speed, and the modified method is...
Research Article

SO(2) and Hamilton-Dirac mechanics

Cestmir BURDIK, Eugen PAAL, Juri VIRKEPU
Pages: 37 - 43
Canonical formalism for plane rotations is developed. This group can be seen as a toy model of the Hamilton-Dirac mechanics with constraints. The Lagrangian and Hamiltonian are explicitly constructed and their physical interpretation are given. The Euler-Lagrange and Hamiltonian canonical equations coincide...
Research Article

On Pauli graded contractions of sl(3, C)

Miloslav HAVLICEK, Jiri PATERA, Edita PELANTOVA, Jiri TOLAR
Pages: 37 - 42
We consider a special fine grading of sl(3, C), where the grading subspaces are geerated by 3 × 3 generalized Pauli matrices. This fine grading decomposes sl(3, C) into eight one­dimensional subspaces. Our aim is to find all contractions of sl(3, C) which preserve this grading. We have found that the...
Research Article

Fractal and Chaotic Solutions of the Discrete Nonlinear Schrödinger Equation in Classical and Quantum Systems

H S DHILLON, F V KUSMARTSEV, K E KÜRTEN
Pages: 38 - 49
We discuss stationary solutions of the discrete nonlinear Schrödinger equation (DNSE) with a potential of the 4 type which is generically applicable to several quantum spin, electron and classical lattice systems. We show that there may arise chaotic spatial structures in the form of incommensurate or...