11,185 research outputs found
Discrete variational integrators and optimal control theory
A geometric derivation of numerical integrators for optimal control problems
is proposed. It is based in the classical technique of generating functions
adapted to the special features of optimal control problems.Comment: 17 page
Tulczyjew's triples and lagrangian submanifolds in classical field theories
In this paper the notion of Tulczyjew's triples in classical mechanics is
extended to classical field theories, using the so-called multisymplectic
formalism, and a convenient notion of lagrangian submanifold in multisymplectic
geometry. Accordingly, the dynamical equations are interpreted as the local
equations defining these lagrangian submanifolds.Comment: 29 page
Geometric numerical integration of nonholonomic systems and optimal control problems
A geometric derivation of numerical integrators for nonholonomic systems and
optimal control problems is obtained. It is based in the classical technique of
generating functions adapted to the special features of nonholonomic systems
and optimal control problems.Comment: 6 pages, 1 figure. Submitted to IFAC Workshop on Lagrangian and
Hamiltonian Methods for Nonlinear Control, Sevilla 200
Relative production rates of He, Be, C in astrophysical environments
We assume an environment of neutrons and -particles of given density
and temperature where nuclear syntheses into He, Be and C
are possible. We investigate the resulting relative abundance as a function of
density and temperature. When the relative abundance of -particles
is between 0.2 and 0.9, or larger than 0.9, the largest production
is Be or C, respectively. When He is mostly
frequently produced for temperatures above about 2 GK whereas the Be
production dominates at smaller temperatures.Comment: 5 pages, 4 figure
Extended Bargmann supergravity from a Lie algebra expansion
In this paper we show how the method of Lie algebra expansions may be used to
obtain, in a simple way, both the extended Bargmann Lie superalgebra and the
Chern-Simons action associated to it in three dimensions, starting from ,
superPoincar\'e and its corresponding Chern-Simons
supergravity.Comment: 17 page
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