Notiziario Scientifico
Notiziario dei seminari di carattere matematico
a cura del Dipartimento 'G. Castelnuovo'
Sapienza Università di Roma
Settimana dal 17 al 23 luglio 2017
Martedì 18 luglio 2017
Ore 14:00, aula di Consiglio
seminario di Analisi Matematica
Ramon G. Plaza (IIMAS - UNAM, Città del Messico)
Density-dependent diffusion models in population dynamics
In this talk I will give a panoramic overview of some mathematical
aspects related to continuous reaction-diffusion population models
endowed with a density-dependent, often degenerate, diffusion
coefficient. In particular, I will discuss their (formal) derivation
from velocity-jump processes and recent advances in the stability
analysis of diffusion-degenerate traveling fronts.
Martedì 18 luglio 2017
Ore 15:15, aula Dal Passo, dipartimento di Matematica,
Università di Roma Tor Vergata
seminario
Rajendra Bhatia (Indian Statistical Institute, Delhi)
The Bures-Wasserstein distance on positive definite matrices I
We will discuss an interesting metric on the space of positive definite
matrices, called the Bures distance in the quantum information literature
and the Wasserstein metric in optimal transport. This has connections with
Riemannian geometry, statistics, QIT and optimal trasport. We will explain
these connections. The two-variable and several-variable mean with respect
to this metric will be described. Our perspective from matrix analysis
leads to simpler proofs and suggests new problems.
Martedì 18 luglio 2017
Ore 16:30, aula Dal Passo, dipartimento di Matematica,
Università di Roma Tor Vergata
seminario
Rajendra Bhatia (Indian Statistical Institute, Delhi)
The Bures-Wasserstein distance on positive definite matrices II
We will discuss an interesting metric on the space of positive definite
matrices, called the Bures distance in the quantum information literature
and the Wasserstein metric in optimal transport. This has connections with
Riemannian geometry, statistics, QIT and optimal trasport. We will explain
these connections. The two-variable and several-variable mean with respect
to this metric will be described. Our perspective from matrix analysis
leads to simpler proofs and suggests new problems.
Mercoledì 19 luglio 2017
Ore 14:00, aula Dal Passo, dipartimento di Matematica,
Università di Roma Tor Vergata
seminario di Geometria Algebrica
Francesco Polizzi (Università della Calabria)
A pair of rigid surfaces with pg=q=2 and K2=8
whose universal cover is not the bidisk
We construct two complex-conjugated rigid surfaces with pg=q=2
and K2=8, whose universal cover is not biholomorphic to the bidisk.
We show that these are the unique surfaces with these invariants and Albanese
map of degree 2, apart a family of product-quotient surfaces constructed by
Penegini. This is a joint work with C. Rito and X. Roulleau.
Giovedì 20 luglio 2017
Ore 11:30, aula di Consiglio
seminario di Probabilità e Statistica Matematica
Elena Di Bernardino (CNAM, Paris)
A test of Gaussianity based on the Euler characteristic
of excursion sets
In the present paper, we deal with a stationary isotropic random field
X:Rd→R and we assume it is partially
observed through some level functionals.
We aim at providing a methodology for a test of Gaussianity
based on this information. More precisely, the level
functionals are given by the Euler characteristic of the excursion
sets above a finite number of levels. On the one hand, we study the
properties of these level functionals under the hypothesis that the
random field X is Gaussian. In particular, we focus on the mapping
that associates to any level u the expected Euler characteristic of
the excursion set above level u. On the other hand, we study the same
level functionals under alternative distributions of X, such as
chi-square, harmonic oscillator and shot noise. In order to validate
our methodology, a part of the work consists in numerical
experimentations. We generate Monte-Carlo samples of Gaussian and
non-Gaussian random fields and compare, from a statistical point of
view, their level functionals.
Goodness-of-fit p-values are displayed for both cases. Simulations
are performed in one dimensional case (d=1) and in two dimensional
case (d=2), using R.
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esclusivamente all'indirizzo di posta elettronica
seminari@mat.uniroma1.it
entro le ore 24 del giovedì precedente la settimana interessata.
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