4,965 research outputs found
Introduction to supergeometry
These notes are based on a series of lectures given by the first author at
the school of `Poisson 2010', held at IMPA, Rio de Janeiro. They contain an
exposition of the theory of super- and graded manifolds, cohomological vector
fields, graded symplectic structures, reduction and the AKSZ-formalism.Comment: Lecture notes of a course held at the school Poisson 2010 at IMPA,
July 2010; 21 pages; references improve
Estimation of multivariate probit models by exact maximum likelihood
In this paper, we develop a new numerical method to estimate a multivariate probit model. To this end, we derive a new decomposition of normal multivariate integrals that has two appealing properties. First, the decomposition may be written as the sum of normal multivariate integrals, in which the highest dimension of the integrands is reduced relative to the initial problem. Second, the domains of integration are bounded and delimited by the correlation coefficients. Application of a Gauss-Legendre quadrature rule to the exact likelihood function of lower dimension allows for a major reduction of computing time while simultaneously obtaining consistent and efficient estimates for both the slope and the scale parameters. A Monte Carlo study shows that the finite sample and asymptotic properties of our method compare extremely favorably to the maximum simulated likelihood estimator in terms of both bias and root mean squared error.Multivariate Probit Model, Simulated and Full Information Maximum Likelihood, Multivariate Normal Distribution, Simulations
On the maximal diphoton width
Motivated by the 750 GeV diphoton excess found at LHC, we compute the maximal
width into that a neutral scalar can acquire through a loop of
charged fermions or scalars as function of the maximal scale at which the
theory holds, taking into account vacuum (meta)stability bounds. We show how an
extra gauge symmetry can qualitatively weaken such bounds, and explore collider
probes and connections with Dark Matter.Comment: 16 pages, 6 figure
Data-driven representations of conical, convex, and affine behaviors
The paper studies conical, convex, and affine models in the framework of
behavioral systems theory. We investigate basic properties of such behaviors
and address the problem of constructing models from measured data. We prove
that closed, shift-invariant, conical, convex, and affine models have the
intersection property, thereby enabling the definition of most powerful
unfalsified models based on infinite-horizon measurements. We then provide
necessary and sufficient conditions for representing conical, convex, and
affine finite-horizon behaviors using raw data matrices, expressing persistence
of excitation requirements in terms of non-negative rank conditions. The
applicability of our results is demonstrated by a numerical example arising in
population ecology
- …