192 research outputs found
A Priori Estimates for Solutions of Boundary Value Problems for Fractional-Order Equations
We consider boundary value problems of the first and third kind for the
diffusionwave equation. By using the method of energy inequalities, we find a
priori estimates for the solutions of these boundary value problems.Comment: 10 pages, no figur
Stochastic Differential Equations Driven by Fractional Brownian Motion and Standard Brownian Motion
We prove an existence and uniqueness theorem for solutions of
multidimensional, time dependent, stochastic differential equations driven
simultaneously by a multidimensional fractional Brownian motion with Hurst
parameter H>1/2 and a multidimensional standard Brownian motion. The proof
relies on some a priori estimates, which are obtained using the methods of
fractional integration, and the classical Ito stochastic calculus. The
existence result is based on the Yamada-Watanabe theorem.Comment: 21 page
On a initial value problem arising in mechanics
We study initial value problem for a system consisting of an integer order
and distributed-order fractional differential equation describing forced
oscillations of a body attached to a free end of a light viscoelastic rod.
Explicit form of a solution for a class of linear viscoelastic solids is given
in terms of a convolution integral. Restrictions on storage and loss moduli
following from the Second Law of Thermodynamics play the crucial role in
establishing the form of the solution. Some previous results are shown to be
special cases of the present analysis
Fractional Loop Group and Twisted K-Theory
We study the structure of abelian extensions of the group of
-differentiable loops (in the Sobolev sense), generalizing from the case of
central extension of the smooth loop group. This is motivated by the aim of
understanding the problems with current algebras in higher dimensions. Highest
weight modules are constructed for the Lie algebra. The construction is
extended to the current algebra of supersymmetric Wess-Zumino-Witten model. An
application to the twisted K-theory on is discussed.Comment: Final version in Commun. Math. Phy
Subdiffusive transport in intergranular lanes on the Sun. The Leighton model revisited
In this paper we consider a random motion of magnetic bright points (MBP)
associated with magnetic fields at the solar photosphere. The MBP transport in
the short time range [0-20 minutes] has a subdiffusive character as the
magnetic flux tends to accumulate at sinks of the flow field. Such a behavior
can be rigorously described in the framework of a continuous time random walk
leading to the fractional Fokker-Planck dynamics. This formalism, applied for
the analysis of the solar subdiffusion of magnetic fields, generalizes the
Leighton's model.Comment: 7 page
Fractional Hamilton formalism within Caputo's derivative
In this paper we develop a fractional Hamiltonian formulation for dynamic
systems defined in terms of fractional Caputo derivatives. Expressions for
fractional canonical momenta and fractional canonical Hamiltonian are given,
and a set of fractional Hamiltonian equations are obtained. Using an example,
it is shown that the canonical fractional Hamiltonian and the fractional
Euler-Lagrange formulations lead to the same set of equations.Comment: 8 page
Solution of generalized fractional reaction-diffusion equations
This paper deals with the investigation of a closed form solution of a
generalized fractional reaction-diffusion equation. The solution of the
proposed problem is developed in a compact form in terms of the H-function by
the application of direct and inverse Laplace and Fourier transforms.
Fractional order moments and the asymptotic expansion of the solution are also
obtained.Comment: LaTeX, 18 pages, corrected typo
Fractional reaction-diffusion equations
In a series of papers, Saxena, Mathai, and Haubold (2002, 2004a, 2004b)
derived solutions of a number of fractional kinetic equations in terms of
generalized Mittag-Leffler functions which provide the extension of the work of
Haubold and Mathai (1995, 2000). The subject of the present paper is to
investigate the solution of a fractional reaction-diffusion equation. The
results derived are of general nature and include the results reported earlier
by many authors, notably by Jespersen, Metzler, and Fogedby (1999) for
anomalous diffusion and del-Castillo-Negrete, Carreras, and Lynch (2003) for
reaction-diffusion systems with L\'evy flights. The solution has been developed
in terms of the H-function in a compact form with the help of Laplace and
Fourier transforms. Most of the results obtained are in a form suitable for
numerical computation.Comment: LaTeX, 17 pages, corrected typo
Constant Curvature Coefficients and Exact Solutions in Fractional Gravity and Geometric Mechanics
We study fractional configurations in gravity theories and Lagrange
mechanics. The approach is based on Caputo fractional derivative which gives
zero for actions on constants. We elaborate fractional geometric models of
physical interactions and we formulate a method of nonholonomic deformations to
other types of fractional derivatives. The main result of this paper consists
in a proof that for corresponding classes of nonholonomic distributions a large
class of physical theories are modelled as nonholonomic manifolds with constant
matrix curvature. This allows us to encode the fractional dynamics of
interactions and constraints into the geometry of curve flows and solitonic
hierarchies.Comment: latex2e, 11pt, 27 pages, the variant accepted to CEJP; added and
up-dated reference
Fractional conservation laws in optimal control theory
Using the recent formulation of Noether's theorem for the problems of the
calculus of variations with fractional derivatives, the Lagrange multiplier
technique, and the fractional Euler-Lagrange equations, we prove a Noether-like
theorem to the more general context of the fractional optimal control. As a
corollary, it follows that in the fractional case the autonomous Hamiltonian
does not define anymore a conservation law. Instead, it is proved that the
fractional conservation law adds to the Hamiltonian a new term which depends on
the fractional-order of differentiation, the generalized momentum, and the
fractional derivative of the state variable.Comment: The original publication is available at http://www.springerlink.com
Nonlinear Dynamic
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