12,618 research outputs found
A Development Environment for Visual Physics Analysis
The Visual Physics Analysis (VISPA) project integrates different aspects of
physics analyses into a graphical development environment. It addresses the
typical development cycle of (re-)designing, executing and verifying an
analysis. The project provides an extendable plug-in mechanism and includes
plug-ins for designing the analysis flow, for running the analysis on batch
systems, and for browsing the data content. The corresponding plug-ins are
based on an object-oriented toolkit for modular data analysis. We introduce the
main concepts of the project, describe the technical realization and
demonstrate the functionality in example applications
On the global and \nabla-filtration dimensions of quasi-hereditary algebras
In this paper we consider how the \nabla-, \Delta- and global dimensions of a
quasi-hereditary algebra are interrelated. We first consider quasi-hereditary
algebras with simple preserving duality and such that if \mu < \lambda then
\nabla fd(L(\mu)) < \nabla fd(L(\lambda)) where \mu, \lambda are in the poset
and L(\mu), L(\lambda) are the corresponding simples. We show that in this case
the global dimension of the algebra is twice its \nabla-filtration dimension.
We then consider more general quasi-hereditary algebras and look at how these
dimensions are affected by the Ringel dual and by two forms of truncation. We
restrict again to quasi-hereditary algebras with simple preserving duality and
consider various orders on the poset compatible with quasi-hereditary structure
and the \nabla-, \Delta- and injective dimensions of the simple and the
costandard modules.Comment: 18 pages, uses xypi
The Midpoint Rule as a Variational--Symplectic Integrator. I. Hamiltonian Systems
Numerical algorithms based on variational and symplectic integrators exhibit
special features that make them promising candidates for application to general
relativity and other constrained Hamiltonian systems. This paper lays part of
the foundation for such applications. The midpoint rule for Hamilton's
equations is examined from the perspectives of variational and symplectic
integrators. It is shown that the midpoint rule preserves the symplectic form,
conserves Noether charges, and exhibits excellent long--term energy behavior.
The energy behavior is explained by the result, shown here, that the midpoint
rule exactly conserves a phase space function that is close to the Hamiltonian.
The presentation includes several examples.Comment: 11 pages, 8 figures, REVTe
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