365 research outputs found
Commuting Flows and Conservation Laws for Noncommutative Lax Hierarchies
We discuss commuting flows and conservation laws for Lax hierarchies on
noncommutative spaces in the framework of the Sato theory. On commutative
spaces, the Sato theory has revealed essential aspects of the integrability for
wide class of soliton equations which are derived from the Lax hierarchies in
terms of pseudo-differential operators. Noncommutative extension of the Sato
theory has been already studied by the author and Kouichi Toda, and the
existence of various noncommutative Lax hierarchies are guaranteed. In the
present paper, we present conservation laws for the noncommutative Lax
hierarchies with both space-space and space-time noncommutativities and prove
the existence of infinite number of conserved densities. We also give the
explicit representations of them in terms of Lax operators. Our results include
noncommutative versions of KP, KdV, Boussinesq, coupled KdV, Sawada-Kotera,
modified KdV equations and so on.Comment: 22 pages, LaTeX, v2: typos corrected, references added, version to
appear in JM
On a direct approach to quasideterminant solutions of a noncommutative KP equation
A noncommutative version of the KP equation and two families of its solutions
expressed as quasideterminants are discussed. The origin of these solutions is
explained by means of Darboux and binary Darboux transformations. Additionally,
it is shown that these solutions may also be verified directly. This approach
is reminiscent of the wronskian technique used for the Hirota bilinear form of
the regular, commutative KP equation but, in the noncommutative case, no
bilinearising transformation is available.Comment: 11 page
Matrix solutions of a noncommutative KP equation and a noncommutative mKP equation
Matrix solutions of a noncommutative KP and a noncommutative mKP equation
which can be expressed as quasideterminants are discussed. In particular, we
investigate interaction properties of two-soliton solutions.Comment: 2 figure
Non-integrability of Self-dual Yang-Mills-Higgs System
We examine integrability of self-dual Yang-Mills system in the Higgs phase,
with taking simpler cases of vortices and domain walls. We show that the vortex
equations and the domain-wall equations do not have Painleve property. This
fact suggests that these equations are not integrable.Comment: 15 pages, no figures, v2: references added, v3: typos corrected, the
final version to appear in NP
Examination of the Singapore Shift in Japan's Foreign Direct Investment in Services in ASEAN
Asia is fast becoming the largest recipient of Japan's foreign direct investment (FDI). Within the Asian region, the Association of Southeast Asian Nations (ASEAN) has been the major investment destination of Japan. In the manufacturing sectors, however, the investment flows from Japan to ASEAN - with Thailand being the largest recipient - has been declining. In contrast, Japan's FDI in the services sectors in ASEAN has been growing rapidly. The recent phenomenon of the Singapore Shift in Japan's FDI in the ASEAN services sectors proves interesting. The prominent strategy of Japanese companies is to establish a commercial presence in Singapore, which they expect to be the hub of Southeast Asia, thereby enabling them to supply services to the entire ASEAN region. The magnitude of the Singapore Shift varies for every services sub-sector. By comparing transport and logistics with finance and insurance industries, this paper considers the critical determinants of the Singapore Shift
Quasideterminant solutions of a non-Abelian Hirota-Miwa equation
A non-Abelian version of the Hirota-Miwa equation is considered. In an
earlier paper [Nimmo (2006) J. Phys. A: Math. Gen. \textbf{39}, 5053-5065] it
was shown how solutions expressed as quasideterminants could be constructed for
this system by means of Darboux transformations. In this paper we discuss these
solutions from a different perspective and show that the solutions are
quasi-Pl\"{u}cker coordinates and that the non-Abelian Hirota-Miwa equation may
be written as a quasi-Pl\"{u}cker relation. The special case of the matrix
Hirota-Miwa equation is also considered using a more traditional, bilinear
approach and the techniques are compared
Noncommutative Burgers Equation
We present a noncommutative version of the Burgers equation which possesses
the Lax representation and discuss the integrability in detail. We find a
noncommutative version of the Cole-Hopf transformation and succeed in the
linearization of it. The linearized equation is the (noncommutative) diffusion
equation and exactly solved. We also discuss the properties of some exact
solutions. The result shows that the noncommutative Burgers equation is
completely integrable even though it contains infinite number of time
derivatives. Furthermore, we derive the noncommutative Burgers equation from
the noncommutative (anti-)self-dual Yang-Mills equation by reduction, which is
an evidence for the noncommutative Ward conjecture. Finally, we present a
noncommutative version of the Burgers hierarchy by both the Lax-pair generating
technique and the Sato's approach.Comment: 24 pages, LaTeX, 1 figure; v2: discussions on Ward conjecture, Sato
theory and the integrability added, references added, version to appear in J.
Phys.
A new approach to deformation equations of noncommutative KP hierarchies
Partly inspired by Sato's theory of the Kadomtsev-Petviashvili (KP)
hierarchy, we start with a quite general hierarchy of linear ordinary
differential equations in a space of matrices and derive from it a matrix
Riccati hierarchy. The latter is then shown to exhibit an underlying 'weakly
nonassociative' (WNA) algebra structure, from which we can conclude, refering
to previous work, that any solution of the Riccati system also solves the
potential KP hierarchy (in the corresponding matrix algebra). We then turn to
the case where the components of the matrices are multiplied using a
(generalized) star product. Associated with the deformation parameters, there
are additional symmetries (flow equations) which enlarge the respective KP
hierarchy. They have a compact formulation in terms of the WNA structure. We
also present a formulation of the KP hierarchy equations themselves as
deformation flow equations.Comment: 25 page
Scattering of Noncommutative Waves and Solitons in a Supersymmetric Chiral Model in 2+1 Dimensions
Interactions of noncommutative waves and solitons in 2+1 dimensions can be
analyzed exactly for a supersymmetric and integrable U(n) chiral model
extending the Ward model. Using the Moyal-deformed dressing method in an
antichiral superspace, we construct explicit time-dependent solutions of its
noncommutative field equations by iteratively solving linear equations. The
approach is illustrated by presenting scattering configurations for two
noncommutative U(2) plane waves and for two noncommutative U(2) solitons as
well as by producing a noncommutative U(1) two-soliton bound state.Comment: 1+13 pages; v2: reference added, version published in JHE
About the self-dual Chern-Simons system and Toda field theories on the noncommutative plane
The relation of the noncommutative self-dual Chern-Simons (NCSDCS) system to
the noncommutative generalizations of Toda and of affine Toda field theories is
investigated more deeply. This paper continues the programme initiated in , where it was presented how it is possible to define Toda
field theories through second order differential equation systems starting from
the NCSDCS system. Here we show that using the connection of the NCSDCS to the
noncommutative chiral model, exact solutions of the Toda field theories can be
also constructed by means of the noncommutative extension of the uniton method
proposed in by Ki-Myeong Lee. Particularly some
specific solutions of the nc Liouville model are explicit constructed.Comment: 24 page
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