40,850 research outputs found
On the boundedness of periodic pseudo-differential operators
In this paper we investigate the -boundedness of certain classes of
periodic pseudo-differential operators. The operators considered arise from the
study of symbols on with limited regularity.Comment: Pseudo-differential operator
Extended Symmetries and Poisson Algebras Associated to Twisted Dirac Structures
In this paper we study the relationship between the extended symmetries of
exact Courant algebroids over a manifold , defined by Bursztyn, Cavalcanti
and Gualtieri, and the Poisson algebras of admissible functions associated to
twisted Dirac structures when acted by Lie groups. We show that the usual
homomorphisms of Lie algebras between the algebras of infinitesimal symmetries
of the action, vector fields on the manifold and the Poisson algebra of
observables, appearing in symplectic geometry, generalize to natural maps of
Leibniz algebras induced both by the extended action and compatible moment maps
associated to it in the context of twisted Dirac structures.Comment: 11 pages, no figure
The known unknown : identification, provenancing, and relocation of pieces of decorative architecture from Roman public buildings and other private structures in Malta
In archaeology a narrative or story is usually reconstructed on the basis of a meticulous study of
material. In normal circumstances, the physical material constitutes the known, while the actual story
remains the unknown until the material is deciphered and put in context. When it comes to certain
aspects of Roman architecture in Malta, and especially the architecture of public buildings, the story is
somewhat reversed. This is because we know of the presence of public buildings but the actual physical
evidence of such structures has for long remained unknown. This study seeks to provide a story, one
that gives a provenance to some of the most important architectural elements found in various local
collections, thereby bringing to the attention of researchers a corpus of data that has hitherto been little
known.peer-reviewe
Some Remarks about Duality, Analytic Torsion and Gaussian Integration in Antisymmetric Field Theories
From a path integral point of view (e.g. \cite{Q98}) physicists have shown
how {\it duality} in antisymmetric quantum field theories on a closed
space-time manifold relies in a fundamental way on Fourier Transformations
of formal infinite-dimensional volume measures. We first review these facts
from a measure theoretical point of view, setting the importance of the Hodge
decomposition theorem in the underlying geometric picture, ignoring the local
symmetry which lead to degeneracies of the action. To handle these degeneracies
we then apply Schwarz's Ansatz showing how duality leads to a factorization of
the analytic torsion of in terms of the partition functions associated to
degenerate "dual" actions, which in the even dimensional case corresponds to
the identification of these partition functions.Comment: 15 pages, LaTe
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