497 research outputs found
Holomorphic Poisson Manifolds and Holomorphic Lie Algebroids
We study holomorphic Poisson manifolds and holomorphic Lie algebroids from
the viewpoint of real Poisson geometry. We give a characterization of
holomorphic Poisson structures in terms of the Poisson Nijenhuis structures of
Magri-Morosi and describe a double complex which computes the holomorphic
Poisson cohomology. A holomorphic Lie algebroid structure on a vector bundle
is shown to be equivalent to a matched pair of complex Lie algebroids
, in the sense of Lu. The holomorphic Lie algebroid
cohomology of is isomorphic to the cohomology of the elliptic Lie algebroid
. In the case when is a holomorphic Poisson
manifold and , such an elliptic Lie algebroid coincides with the
Dirac structure corresponding to the associated generalized complex structure
of the holomorphic Poisson manifold.Comment: 29 pages, v2: paper split into two, part 1 of 2, v3: two references
added, v4: final version to appear in International Mathematics Research
Notice
Hamilton-Jacobi formalism for Linearized Gravity
In this work we study the theory of linearized gravity via the
Hamilton-Jacobi formalism. We make a brief review of this theory and its
Lagrangian description, as well as a review of the Hamilton-Jacobi approach for
singular systems. Then we apply this formalism to analyze the constraint
structure of the linearized gravity in instant and front-form dynamics.Comment: To be published in Classical and Quantum Gravit
Cohomology of skew-holomorphic Lie algebroids
We introduce the notion of skew-holomorphic Lie algebroid on a complex
manifold, and explore some cohomologies theories that one can associate to it.
Examples are given in terms of holomorphic Poisson structures of various sorts.Comment: 16 pages. v2: Final version to be published in Theor. Math. Phys.
(incorporates only very minor changes
A heterotic sigma model with novel target geometry
We construct a (1,2) heterotic sigma model whose target space geometry
consists of a transitive Lie algebroid with complex structure on a Kaehler
manifold. We show that, under certain geometrical and topological conditions,
there are two distinguished topological half--twists of the heterotic sigma
model leading to A and B type half--topological models. Each of these models is
characterized by the usual topological BRST operator, stemming from the
heterotic (0,2) supersymmetry, and a second BRST operator anticommuting with
the former, originating from the (1,0) supersymmetry. These BRST operators
combined in a certain way provide each half--topological model with two
inequivalent BRST structures and, correspondingly, two distinct perturbative
chiral algebras and chiral rings. The latter are studied in detail and
characterized geometrically in terms of Lie algebroid cohomology in the
quasiclassical limit.Comment: 83 pages, no figures, 2 references adde
Nonlocal regularization of abelian models with spontaneous symmetry breaking
We demonstrate how nonlocal regularization is applied to gauge invariant
models with spontaneous symmetry breaking. Motivated by the ability to find a
nonlocal BRST invariance that leads to the decoupling of longitudinal gauge
bosons from physical amplitudes, we show that the original formulation of the
method leads to a nontrivial relationship between the nonlocal form factors
that can appear in the model.Comment: 11 pages, uses amsart. To appear in Mod. Phys. Lett
Integral Grothendieck-Riemann-Roch theorem
We show that, in characteristic zero, the obvious integral version of the
Grothendieck-Riemann-Roch formula obtained by clearing the denominators of the
Todd and Chern characters is true (without having to divide the Chow groups by
their torsion subgroups). The proof introduces an alternative to Grothendieck's
strategy: we use resolution of singularities and the weak factorization theorem
for birational maps.Comment: 24 page
Weak splittings of quotients of Drinfeld and Heisenberg doubles
We investigate the fine structure of the simplectic foliations of Poisson
homogeneous spaces. Two general results are proved for weak splittings of
surjective Poisson submersions from Heisenberg and Drinfeld doubles. The
implications of these results are that the torus orbits of symplectic leaves of
the quotients can be explicitly realized as Poisson-Dirac submanifolds of the
torus orbits of the doubles. The results have a wide range of applications to
many families of real and complex Poisson structures on flag varieties. Their
torus orbits of leaves recover important families of varieties such as the open
Richardson varieties.Comment: 20 pages, AMS Late
New Realizations of the Maximal Satake Compactifications of Riemannian Symmetric Spaces of Noncompact Type
We give new realizations of the maximal Satake compactifications of Riemannian symmetric spaces of noncompact type as orbit closures inside Grassmannians and orthogonal groups. Our constructions are partially motivated by Poisson geometry.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43216/1/11005_2004_Article_5379183.pd
Budget impact analysis of rituximab biosimilar in Italy from the hospital and payer perspectives
Introduction: This article aims at investigating the 5-year budget impact of rituximab biosimilars in Italy. Methods: A budget impact analysis model was developed in accordance with the International Society For Pharmacoeconomics and Outcomes Research recommendations. Drug acquisition and drug administration costs were considered since the risk/benefit profile of biosimilars and the originator was assumed to be overlapping. The perspectives of hospitals and payers were used. Input data were retrieved from the literature and validated/integrated by an expert panel of seven clinicians from various Italian regions. A dynamic incidence-based approach was used. Results: From the hospital perspective, adopting a rituximab biosimilar would produce savings of €79.2 and €153.6 million over 3 and 5 years, respectively. The results are very similar if the payer perspective is considered, with a cumulated savings of about €153.4 million in 5 years. Lymphoma and chronic lymphocytic leukaemia would account for the most significant savings. Discussion: Despite its limitations, this study provides the first Italian evaluation of the financial impact of rituximab biosimilars and also incorporates the effects of biosimilars on the pricing strategies of the originator (dynamic impact). This dynamic effect is more relevant than the impact of the treatment shift from the originator to biosimilars. Our hope is that these savings will be used to cover new cost-effective drugs and not just for cost-cutting policies
- …