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Probing Black Hole Magnetic Fields with QEDMay 25 2018The effect of vacuum birefringence is one of the first predictions of quantum electrodynamics (QED): the presence of a charged Dirac field makes the vacuum birefringent when threaded by magnetic fields. This effect, extremely weak for terrestrial magnetic ... More

Vacuum birefringence and the X-ray polarization from black-hole accretion disksMar 10 2018Apr 04 2018In the next decade, x-ray polarimetry will open a new window on the high-energy Universe, as several missions that include an x-ray polarimeter are currently under development. Observations of the polarization of x-rays coming from the accretion disks ... More

Strongly Magnetized Sources: QED and X-ray PolarizationFeb 01 2018Jul 17 2018Radiative corrections of quantum electrodynamics cause a vacuum threaded by magnetic field to be birefringent. This means that radiation of different polarizations travels at different speeds. Even in the strong magnetic fields of astrophysical sources ... More

Polluting White Dwarfs with Perturbed Exo-CometsFeb 24 2017Apr 27 2017We present a model to account for the observed debris disks around young white dwarfs and the presence of metal-lines in their spectra. Stellar evolution models predict that the mass-loss on the AGB will be pulsed; furthermore, observations indicate that ... More

Multiscale modeling of vascularized tissues via non-matching immersed methodsAug 29 2019We consider a multiscale approach based on immersed methods for the efficient computational modeling of tissues composed of an elastic matrix (in two or three-dimensions) and a thin vascular structure (treated as a co-dimension two manifold) at a given ... More

Globular cluster absolute ages from cooling brown dwarfsFeb 01 2017Globular clusters are the oldest conglomerates of stars in our Galaxy and can be useful laboratories to test theories from stellar evolution to cosmology. In this paper, we present a new method to estimate the absolute age of a globular cluster from observations ... More

Distances to the globular clusters 47 Tucanae and NGC 362 using Gaia DR2 parallaxesJul 18 2018Sep 10 2018Using parallaxes from Gaia DR2, we estimate the distance to the globular clusters 47 Tuc and NGC 362, taking advantage of the background stars in the Small Magellanic Cloud and quasars to account for various parallax systematics. We found the parallax ... More

Using Galaxy Formation Simulations to optimise LIGO Follow-Up ObservationsDec 13 2016The recent discovery of gravitational radiation from merging black holes poses a challenge of how to organize the electromagnetic follow-up of gravitational-wave events as well as observed bursts of neutrinos. We propose a technique to select the galaxies ... More

The Onset of Convective Coupling and Freezing in the White Dwarfs of 47 TucanaeSep 23 2017Oct 13 2017Using images from the Hubble Space Telescope Advanced Camera for Surveys, we measure the rate of cooling of white dwarfs in the globular cluster 47 Tucanae and compare it to modelled cooling curves. We examine the effects of the outer convective envelope ... More

A Massive Magnetic Helium Atmosphere White Dwarf Binary in a Young Star ClusterJun 11 2019We have searched the Gaia DR2 catalogue for previously unknown hot white dwarfs in the direction of young open star clusters. The aim of this experiment was to try and extend the initial-final mass relation (IFMR) to somewhat higher masses, potentially ... More

Glass glass transition and new dynamical singularity points in an analytically solvable p-spin glass like modelNov 22 2004We introduce and analytically study a generalized p-spin glass like model that captures some of the main features of attractive glasses, recently found by Mode Coupling investigations, such as a glass/glass transition line and dynamical singularity points ... More

Robust Principal Component Analysis in Hilbert spacesJun 01 2016We propose a stable version of Principal Component Analysis (PCA) in the general framework of a separable Hilbert space. It consists in interpreting the projection on the first eigenvectors as a step function applied to the spectrum of the covariance ... More

Kernel Spectral ClusteringJun 21 2016We investigate the question of studying spectral clustering in a Hilbert space where the set of points to cluster are drawn i.i.d. according to an unknown probability distribution whose support is a union of compact connected components. We modify the ... More

Robust dimension-free Gram operator estimatesNov 19 2015In this paper we investigate the question of estimating the Gram operator by a robust estimator from an i.i.d. sample in a separable Hilbert space and we present uniform bounds that hold under weak moment assumptions. The approach consists in first obtaining ... More

Stallings' decomposition theorem for totally disconnected locally compact groupsJun 07 2015Sep 15 2015An analogue of Stallings' decomposition theorem is proved for totally disconnected locally compact groups, i.e., a totally disconnected locally compact group $G$ with more than one end splits either as an HNN-extension $H\ast_K^t$ or non-trivially as ... More

Rational discrete first degree cohomology for totally disconnected locally compact groupsJun 07 2015Mar 15 2017It is well-known that the existence of more than two ends in the sense of J.R. Stallings for a finitely generated discrete group $G$ can be detected on the cohomology group $\mathrm{H}^1(G,R[G])$, where $R$ is either a finite field, the ring of integers ... More

An outline of polar spaces: basics and advancesMar 22 2013This paper is an extended version of a series of lectures on polar spaces given during the workshop and conference 'Groups and Geometries', held at the Indian Statistical Institute in Bangalore in December 2012. The aim of this paper is to give an overview ... More

The center of twisted affine quantum algebras at odd roots of 1Nov 21 2011This paper focuses on twisted affine quantum algebras: an integer form is chosen, and the center of its specialization at odd roots of 1 (of order bigger than 3 in case D_4^{(3)}, bigger than 1 otherwise) is described.

Higgs physics beyond the SM: the non-linear EFT approachMay 04 2015Depending on whether electroweak physics beyond the Standard Model is based on a linear or on a non-linear implementation of the electroweak symmetry breaking, a linear or a chiral Effective Lagrangian is more appropriate. In this talk, the main low-energy ... More

Topological entropy for locally linearly compact vector spaces and field extensionsSep 06 2018Let $\mathbb{K}$ be a discrete field and $(V, \phi)$ a flow over the category of locally linearly compact $\mathbb{K}$-spaces. Here we give the formulas to compute the topological entropy of $(V,\phi)$ subject to the extension or the restriction of scalars. ... More

Robust dimension-free Gram operator estimatesNov 19 2015Mar 31 2017In this paper we investigate the question of estimating the Gram operator by a robust estimator from an i.i.d. sample in a separable Hilbert space and we present uniform bounds that hold under weak moment assumptions. The approach consists in first obtaining ... More

The Neutrino OptionApr 15 2019Apr 27 2019The Neutrino Option is a scenario where the Higgs mass is generated at the same time as neutrino masses in the type-I seesaw model. This framework provides a dynamical origin for the scalar potential of the Standard Model and suggests a new approach to ... More

From the Drinfeld realization to the Drinfeld-Jimbo presentation of affine quantum algebras: the injectivityJul 01 2014In this paper the surjective homomorphism from the Drinfeld realization to the Drinfeld and Jimbo presentation of affine quantum algebras is proved to be injective. A consequence of the arguments used in the paper is the triangular decomposition of the ... More

The R-matrix for (twisted) affine quantum algebrasNov 17 2011In this paper an exponential multiplicative formula for the R-matrix is provided for the twisted affine quantum algebras.

XMM-Newton detection of warm/hot integalactic medium at z~0.01Dec 03 2002May 08 2004We report a ~3 sigma detection of a 21.82 A absorption feature in the direction of the BL Lac MRK 421 which is interpreted as OVII K(alpha) at z~0.01. This corresponds to the redshift of a H absorber in a cosmic void detected by HST along the line of ... More

Signatures of dynamical scalarsMay 18 2015Effective Lagrangians represent an important, model independent tool for studying physics beyond the Standard Model, via its impact on electroweak scale observables. In particular, two different effective descriptions may be appropriate, depending on ... More

An Obata singular theorem for stratified spacesNov 25 2015Consider a stratified space with a positive Ricci lower bound on the regular set and no cone angle larger than 2$\pi$. For such stratified space we know that the first non-zero eigenvalue of the Laplacian is larger than or equal to the dimension. We prove ... More

PAC-Bayesian bounds for Principal Component Analysis in Hilbert spacesNov 19 2015Based on some new robust estimators of the covariance matrix, we propose stable versions of Principal Component Analysis (PCA) and we qualify it independently of the dimension of the ambient space. We first provide a robust estimator of the orthogonal ... More

A Multi-Mass Velocity Dispersion Model of 47 Tucanae Indicates No Evidence for an Intermediate Mass Black HoleJul 09 2018In this paper we analyze stellar proper motions in the core of the globular cluster 47 Tucanae to explore the possibility of an intermediate mass black hole (IMBH) influence on the stellar dynamics. Our use of short wavelength photometry affords us an ... More

Phase coexistence and relaxation of the spherical frustrated Blume-Emery-Griffiths model with attractive particles couplingNov 19 2003We study the equilibrium and dynamical properties of a spherical version of the frustrated Blume-Emery-Griffiths model at mean field level for attractive particle-particle coupling (K>0). Beyond a second order transition line from a paramagnetic to a ... More

Dynamics and thermodynamics of the spherical frustrated Blume-Emery-Griffiths modelJan 31 2003We introduce a spherical version of the frustrated Blume-Emery-Griffiths model and solve exactly the statics and the Langevin dynamics for zero particle-particle coupling (K=0). In this case the model exhibits an equilibrium transition from a disordered ... More

A Multi-Mass Velocity Dispersion Model of 47 Tucanae Indicates No Evidence for an Intermediate Mass Black HoleJul 09 2018May 03 2019In this paper, we analyze stellar proper motions in the core of the globular cluster 47 Tucanae to explore the possibility of an intermediate-mass black hole (IMBH) influence on the stellar dynamics. Our use of short-wavelength photometry affords us an ... More

Hunting for ancient brown dwarfs: the developing field of brown dwarfs in globular clustersMar 15 2019The detection of brown dwarfs in globular star clusters will allow us to break the degeneracies in age, mass and composition that affect our current models, and therefore to constrain the physics of their atmospheres and interiors. Furthermore, detecting ... More

Metallicity effects on synthetic Cepheid Period-Luminosity relationsJan 05 1999Apr 08 1999On the basis of new theoretical results useful predictions concerning the Period-Luminosity (PLR) and Period-Luminosity-Color (PLCR) relations both for optical and infrared magnitudes are presented. It is shown that, following the dependence of the instability ... More

The Local Yamabe Constant of Einstein Stratified SpacesNov 28 2014On a compact stratified space (X, g) there exists a metric of constant scalar curvature in the conformal class of g, if the scalar curvature satisfies an integrability condition and if the Yamabe constant of X is strictly smaller than the local Yamabe ... More

Drinfeld Realization of Affine Quantum Algebras: The RelationsJun 25 2014In this paper the structure of the Drinfeld realization $\Udr_q$ of affine quantum algebras (both untwisted and twisted) is described in details, and its defining relations are studied and simplified. As an application, a homomorphism $\psi$ from this ... More

The Neutrino OptionApr 15 2019The Neutrino Option is a scenario where the Higgs mass is generated at the same time as neutrino masses in the type-I seesaw model. This framework provides a dynamical origin for the scalar potential of the Standard Model and suggests a new approach to ... More

The corank of a flow over the category of linearly compact vector spacesMar 11 2018Sep 06 2018For a topological flow $(V,\phi)$ - i.e., $V$ is a linearly compact vector space and $\phi$ a continuous endomorphism of $V$ - we gain a deep understanding of the relationship between $(V,\phi)$ and the Bernoulli shift: a topological flow $(V,\phi)$ is ... More

Robust Principal Component Analysis in Hilbert spacesJun 01 2016Mar 31 2017We propose a stable version of Principal Component Analysis (PCA) in the general framework of a separable Hilbert space. It consists in interpreting the projection on the first eigenvectors as a step function applied to the spectrum of the covariance ... More

Shape derivatives for minima of integral functionalsJan 13 2014For $\Omega$ varying among open bounded sets in ${\mathbb R} ^n$, we consider shape functionals $J (\Omega)$ defined as the infimum over a Sobolev space of an integral energy of the kind $\int _\Omega[ f (\nabla u) + g (u) ]$, under Dirichlet or Neumann ... More

A space-time Trefftz discontinuous Galerkin method for the first-order acoustic wave equationsOct 25 2016We introduce a space-time Trefftz discontinuous Galerkin method for the first-order transient acoustic wave equations in arbitrary space dimensions, extending the scheme of Kretzschmar et al. (2016, IMA J. Numer. Anal., 36, 1599-1635). Test and trial ... More

Calibration setup for ultralow-current transresistance amplifiersOct 17 2016We describe a calibration setup for the transresistance of low-current amplifiers, based on the capacitance-charging method. The calibration can be performed in the current range of typical interest for electron counting experiments. The setup implementation ... More

Implementing the Stochastics Brane Calculus in a Generic Stochastic Abstract MachineNov 17 2012In this paper, we deal with the problem of implementing an abstract machine for a stochastic version of the Brane Calculus. Instead of defining an ad hoc abstract machine, we consider the generic stochastic abstract machine introduced by Lakin, Paulev\'e ... More

Determination of Low Energy Constants and testing Chiral Perturbation Theory at Next to Next to Leading OrderApr 23 2009We present the results of a search for relations between observables that are independent of the Chiral Pertubation Theory (ChPT) Next-to-Next-to-Leading Order (NNLO) Low-Energy Constants (LECs). We have found some relations between observables in $\pi\pi$, ... More

The galactic double-mode Cepheids II. Properties of the generalized phase differencesDec 05 1996By considering the least-squares fits of the double-mode Cepheid light curves discussed in Paper I we defined their properties by their Fourier parameters and generalized phase differences $G_{i,j}$. When plotting the latter quantities as a function of ... More

A Fast Reconstruction Algorithm for Gene NetworksJan 30 2004This paper deals with gene networks whose dynamics is assumed to be generated by a continuous-time, linear, time invariant, finite dimensional system (LTI) at steady state. In particular, we deal with the problem of network reconstruction in the typical ... More

Four Years of Extreme Ultraviolet Observations of Markarian 421. I: Spectral AnalysisAug 01 2000We analyzed the ~950 ks of spectroscopic data accumulated by the Extreme Ultraviolet Explorer (EUVE) satellite between 1994 and 1997 for the BL Lacertae object Markarian 421. The EUV spectrum is well detected in the 70-110 A (112-177 eV) range and can ... More

The area measure of log-concave functions and related inequalitiesDec 12 2011Dec 21 2011On the class of log-concave functions on $\R^n$, endowed with a suitable algebraic structure, we study the first variation of the total mass functional, which corresponds to the volume of convex bodies when restricted to the subclass of characteristic ... More

Finitely generated abelian groups of unitsMay 06 2019In 1960 Fuchs posed the problem of characterizing the groups which are the groups of units of commutative rings. In the following years, some partial answers have been given to this question in particular cases. In this paper we address Fuchs' question ... More

Backtesting Lambda Value at RiskFeb 24 2016Jun 02 2017A new risk measure, the lambda value at risk (Lambda VaR), has been recently proposed from a theoretical point of view as a generalization of the value at risk (VaR). The Lambda VaR appears attractive for its potential ability to solve several problems ... More

On certain submodules of Weyl modules for SO(2n+1,F) with char(F) = 2May 20 2013For $k = 1, 2,...,n-1$ let $V_k = V(\lambda_k)$ be the Weyl module for the special orthogonal group $G = \mathrm{SO}(2n+1,\F)$ with respect to the $k$-th fundamental dominant weight $\lambda_k$ of the root system of type $B_n$ and put $V_n = V(2\lambda_n)$. ... More

Codes and caps from orthogonal GrassmanniansMar 22 2013Jun 28 2013In this paper we investigate linear error correcting codes and projective caps related to the Grassmann embedding $\varepsilon_k^{gr}$ of an orthogonal Grassmannian $\Delta_k$. In particular, we determine some of the parameters of the codes arising from ... More

A $C^1$ regularity result for the inhomogeneous normalized infinity LaplacianJun 17 2015We prove that the unique solution to the Dirichlet problem with constant source term for the inhomogeneous normalized infinity Laplacian on a convex domain of $\mathbb{R}^N$ is of class $C^1$. The result is obtained by showing as an intermediate step ... More

Dimension-free PAC-Bayesian bounds for the estimation of the mean of a random vectorFeb 12 2018In this paper, we present a new estimator of the mean of a random vector, computed by applying some threshold function to the norm. Non asymptotic dimension-free almost sub-Gaussian bounds are proved under weak moment assumptions, using PAC-Bayesian inequalities. ... More

Geometries arising from trilinear forms on low-dimensional vector spacesMar 20 2017Let ${\mathcal G}_k(V)$ be the $k$-Grassmannian of a vector space $V$ with $\dim V=n$. Given a hyperplane $H$ of ${\mathcal G}_k(V)$, we define in [I. Cardinali, L. Giuzzi, A. Pasini, A geometric approach to alternating $k$-linear forms, J. Algebraic ... More

Dimension-free PAC-Bayesian bounds for matrices, vectors, and linear least squares regressionDec 07 2017Dec 31 2017This paper is focused on dimension-free PAC-Bayesian bounds, under weak polynomial moment assumptions, allowing for heavy tailed sample distributions. It covers the estimation of the mean of a vector or a matrix, with applications to least squares linear ... More

Determination of Low Energy Constants and testing Chiral Perturbation Theory at order $p^6$ (NNLO)Sep 24 2009We present the results of a search for relations between observables that are independent of the Chiral Perturbation Theory (ChPT) Next-to-Next-to-Leading Order (NNLO) Low-Energy Constants (LECs). We have found some relations between observables in $\pi\pi$, ... More

From Risk Measures to Research MeasuresMay 04 2012In order to evaluate the quality of the scientific research, we introduce a new family of scientific performance measures, called Scientific Research Measures (SRM). Our proposal originates from the more recent developments in the theory of risk measures ... More

The galactic double-mode Cepheids I. Frequency analysis of the light curves and comparison with single-mode CepheidsDec 05 1996We submitted the available photometric V data of all the known galactic Double Mode Cepheids (DMCs) to a careful frequency analysis with the aim of detecting in each case the importance of the harmonics and of the cross coupling terms. For each object, ... More

Chiral Symmetry and Charmonium Decays to Two PseudoscalarsSep 23 2011We apply hard pion Chiral Perturbation Theory to charmonium decays to $\pi\pi$, $KK$ and $\eta\eta$. We first discuss why we expect to be able to provide results for the chiral logarithms in $\chi_{c0}$ and $\chi_{c2}$ decays to two pseudoscalars while ... More

Vector Formfactors in Hard Pion Chiral Perturbation TheoryNov 30 2010We use three-flavour hard pion Chiral Perturbation Theory (HPChPT) in both the heavy meson and a relativistic formulation to calculate the chiral logarithms $m^2\log(m^2/\mu^2)$ contributing to the formfactors of the $B_{(s)}\rightarrow \pi,K,\eta$ and ... More

Bernoulli free boundary problem for the infinity LaplacianApr 23 2018We study the interior Bernoulli free boundary for the infinity Laplacian. Our results cover existence, uniqueness, and characterization of solutions (above a threshold representing the "infinity Bernoulli constant"), their regularity, and their relationship ... More

CO2 packing polymorphism under confinement in cylindrical nanoporesSep 14 2017We investigate the effect of cylindrical nano-confinement on the phase behaviour of a rigid model of carbon dioxide using both molecular dynamics and well tempered metadynamics. To this aim we study a simplified pore model across a parameter space comprising ... More

An RBF-PSO Based Approach for Modeling Prostate CancerDec 12 2015Prostate cancer is one of the most common cancers in men. It is characterized by a slow growth and it can be diagnosed in an early stage by observing the Prostate Specific Antigen (PSA). However, a relapse after the primary therapy could arise and different ... More

Minimum distance of Symplectic Grassmann codesMar 17 2015Sep 09 2015We introduce the Symplectic Grassmann codes as projective codes defined by symplectic Grassmannians, in analogy with the orthogonal Grassmann codes introduced in [4]. Note that the Lagrangian-Grassmannian codes are a special class of Symplectic Grassmann ... More

Enumerative Coding for Line Polar Grassmannians with applications to codesDec 17 2014Apr 10 2018A $k$-polar Grassmannian is the geometry having as pointset the set of all $k$-dimensional subspaces of a vector space $V$ which are totally isotropic for a given non-degenerate bilinear form $\mu$ defined on $V.$ Hence it can be regarded as a subgeometry ... More

On the Dirichlet and Serrin problems for the inhomogeneous infinity Laplacian in convex domains: Regularity and geometric resultsOct 22 2014May 02 2015Given an open bounded subset $\Omega$ of $\mathbb{R}^n$, which is convex and satisfies an interior sphere condition, we consider the pde $-\Delta_{\infty} u = 1$ in $\Omega$, subject to the homogeneous boundary condition $u = 0$ on $\partial \Omega$. ... More

Minimum distance of Line Orthogonal Grassmann Codes in even characteristicMay 30 2016In this paper we determine the minimum distance of orthogonal line-Grassmann codes for $q$ even. The case $q$ odd was solved in "I. Cardinali, L. Giuzzi, K. Kaipa, A. Pasini, Line Polar Grassmann Codes of Orthogonal Type, J. Pure Applied Algebra." We ... More

Detection through exchange energy of multipartite entanglement in spin ringsJun 20 2014We investigate multipartite entanglement in rings of arbitrary spins with antiferromagnetic interactions between nearest neighbors. In particular, we show that the non-degenerate ground state of rings formed by an even number ($N$) of spins is $N$-partite ... More

Backtesting Lambda Value at RiskFeb 24 2016Jun 12 2016A new risk measure, the lambda value at risk (Lambda VaR), has been recently proposed from a theoretical point of view as a generalization of the value at risk (VaR). The Lambda VaR appears attractive for its potential ability to solve several problems ... More

The interpretations by experimenters of experiments on 'time dilation': 1940-1970 circaAug 04 2000Nov 07 2013Experimental tests on `time dilation' began in 1938 with Ives and Stilwell's work of the transverse Doppler effect due to atoms in inertial flight. Rossi and Hall (1941) inaugurated the era of fast moving elementary particles that dominated the scene ... More

Relations at Order $p^6$ in Chiral Perturbation TheoryJun 17 2009Sep 03 2009We report on a search of relations valid at order $p^6$ in Chiral Perturbation Theory. We have found relations between $\pi\pi$, $\pi K$ scattering, $K_{\ell4}$ decays, masses and decay constants and scalar and vector form factors. In this paper we give ... More

Evidence for Disk Photoevaporation Driven by the Central StarAug 17 2009The lifetime of isolated protoplanetary disks is thought to be set by the combination of viscous accretion and photoevaporation driven by stellar high-energy photons. Observational evidence for magnetospheric accretion in young sun-like stars is robust. ... More

Enumerative Coding for Line Polar Grassmannians with applications to codesDec 17 2014Mar 01 2016A $k$-polar Grassmannian is the geometry having as pointset the set of all $k$-dimensional subspaces of a vector space $V$ which are totally isotropic for a given non-degenerate bilinear form $\mu$ defined on $V.$ Hence it can be regarded as a subgeometry ... More

Stray-light restoration of full-disk CaII K solar observations: a case studyApr 07 2008AIMS: We investigate whether restoration techniques, such as those developed for application to current observations, can be used to remove stray-light degradation effects on archive CaII K full-disk observations. We analyze to what extent these techniques ... More

The Dispersal of Planet-forming discs: Theory confronts ObservationsApr 01 2017Apr 04 2017Discs of gas and dust around Myr-old stars are a by-product of the star formation process and provide the raw material to form planets. Hence, their evolution and dispersal directly impact what type of planets can form and affect the final architecture ... More

Veronesean embeddings of dual polar spaces of orthogonal typeMar 22 2013Given a point-line geometry P and a pappian projective space S,a veronesean embedding of P in S is an injective map e from the point-set of P to the set of points of S mapping the lines of P onto non-singular conics of S and such that e(P) spans S. In ... More

Rigidity results for variational infinity ground statesFeb 03 2017Jun 28 2017We prove two rigidity results for a variational infinity ground state $u$ of an open bounded convex domain $\Omega \subset \mathbb{R}^n$. They state that $u$ coincides with a multiple of the distance from the boundary of $\Omega$ if either $|\nabla u|$ ... More

Multivariate semi-discrete sampling type operators: pointwise approximation propertiesMay 24 2016In this paper multivariate extension of the generalized Durrmeyer sampling type series are considered. We establish a Voronovskaja type formula and a quantitative version. Finally some particular examples are discussed.

Line Hermitian Grassmann Codes and their ParametersJun 30 2017Apr 10 2018In this paper we introduce and study line Hermitian Grassmann codes as those subcodes of the Grassmann codes associated to the $2$-Grassmannian of a Hermitian polar space defined over a finite field of square order. In particular, we determine their parameters ... More

On the supremal version of the Alt-Caffarelli minimization problemNov 30 2018This is a companion paper to our recent work [9], where we studied the interior Bernoulli free boundary for the infinity Laplacian. Here we consider its variational side, which corresponds to the supremal version of the Alt--Caffarelli minimization problem. ... More

A duality theory for non-convex problems in the Calculus of VariationsJul 11 2016We present a new duality theory for non-convex variational problems, under possibly mixed Dirichlet and Neumann boundary conditions. The dual problem reads nicely as a linear programming problem, and our main result states that there is no duality gap. ... More

Exploring the relationship between the magnitudes of seismic eventsJul 20 2015The distribution of the magnitudes of seismic events is generally assumed to be independent on past seismicity. However, by considering events in causal relation, for example mother-daughter, it seems natural to assume that the magnitude of a daughter ... More

Electron-phonon interaction on bundled structures: static and transport propertiesOct 20 2000We study the small-polaron problem of a single electron interacting with the lattice for the Holstein model in the adiabatic limit on a comb lattice, when the electron-phonon interaction acts only on the base sites. The ground state properties can be ... More

Hard Pion Chiral Perturbation Theory for $B\toπ$ and $D\toπ$ FormfactorsJun 07 2010Oct 22 2010We use one-loop Heavy Meson Chiral Perturbation Theory (HMCHPT) as well as a relativistic formulation to calculate the chiral logarithms $m^2_\pi\log{\left(m^2_\pi/\mu^2\right)}$ contributing to the formfactors of the semileptonic $B\rightarrow \pi$ decays ... More

A new global fit of the $L^r_i$ at next-to-next-to-leading order in Chiral Perturbation TheoryMar 30 2011Oct 03 2011A new fit is done to obtain numerical values for the order $p^4$ low-energy-constants $L_i^r$ in Chiral Perturbation Theory. This includes both new data and new calculated observables. We take into account masses, decay constants, $K_{\ell4}$, $\pi\pi$ ... More

Model of human collective decision-making in complex environmentsJul 08 2015Oct 30 2015A continuous-time Markov process is proposed to analyze how a group of humans solves a complex task, consisting in the search of the optimal set of decisions on a fitness landscape. Individuals change their opinions driven by two different forces: (i) ... More

Proof of the Honeycomb Asymptotics for Optimal Cheeger ClustersJun 30 2017We prove that, in the limit as $k \to+ \infty$, the hexagonal honeycomb solves the optimal partition problem in which the criterion is minimizing the largest among the Cheeger constants of $k$ mutually disjoint cells in a planar domain. As a by-product, ... More

A pixel-based approach to massive lesion detection in X-ray mammographyJul 20 2005A system for the automated detection of massive lesions in mammograms is presented. The approach we adopted is a pixel-based and multi-level one. Each pixel in a mammogram is flagged with the appropriate class membership, e.g. massive lesions or normal ... More

On the characterization of some classes of proximally smooth setsMay 13 2013We provide a complete characterization of closed sets with empty interior and positive reach in $\mathbb{R}^2$. As a consequence, we characterize open bounded domains in $\mathbb{R}^2$ whose high ridge and cut locus agree, and hence $C^1$ planar domains ... More

Finitely generated abelian groups of unitsMay 06 2019Jul 13 2019In 1960 Fuchs posed the problem of characterizing the groups which are the groups of units of commutative rings. In the following years, some partial answers have been given to this question in particular cases. In this paper we address Fuchs' question ... More

Characterization of stadium-like domains via boundary value problems for the infinity LaplacianSep 05 2015We give a complete characterization, as "stadium-like domains", of convex subsets $\Omega$ of $\mathbb{R}^n$ where a solution exists to Serrin-type overdetermined boundary value problems in which the operator is either the infinity Laplacian or its normalized ... More

A new symmetry criterion based on the distance function and applications to PDE'sJul 26 2012We prove that, if $\Omega\subset \mathbb{R}^n$ is an open bounded starshaped domain of class $C^2$, the constancy over $\partial \Omega$ of the function $$\varphi(y) = \int_0^{\lambda(y)} \prod_{j=1}^{n-1}[1-t \kappa_j(y)]\, dt$$ implies that $\Omega$ ... More

Rational discrete cohomology for totally disconnected locally compact groupsMar 09 2015Mar 15 2017Rational discrete cohomology and homology for a totally disconnected locally compact group $G$ is introduced and studied. The $\mathrm{Hom}$-$\otimes$ identities associated to the rational discrete bimodule $\mathrm{Bi}(G)$ allow to introduce the notion ... More

Physics and astrophysics of strong magnetic field systems with eXTPDec 11 2018In this paper we present the science potential of the enhanced X-ray Timing and Polarimetry (eXTP) mission for studies of strongly magnetized objects. We will focus on the physics and astrophysics of strongly magnetized objects, namely magnetars, accreting ... More

A new magnitude-dependent ETAS model for earthquakesApr 22 2015We propose a new version of the ETAS model, which we also analyze theoretically. As for the standard ETAS model, we assume the Gutenberg-Richter law as a probability density function for background events' magnitude. Instead, the magnitude of triggered ... More

Rational discrete cohomology for totally disconnected locally compact groupsMar 09 2015Rational discrete cohomology and homology for a totally disconnected locally compact group $G$ is introduced and studied. The $\mathrm{Hom}$-$\otimes$ identities associated to the rational discrete bimodule $\mathrm{Bi}(G)$ allow to introduce the notion ... More

Sphere theorems for RCD and stratified spacesJul 08 2019Jul 09 2019We prove topological sphere theorems for RCD(n-1, n) spaces which generalize Colding's results and Petersen's result to the RCD setting. We also get an improved sphere theorem in the case of Einstein stratified spaces.

The Brunn-Minkowski inequality for the principal eigenvalue of fully nonlinear homogeneous elliptic operatorsMar 15 2019We prove that the principal eigenvalue of any fully nonlinear homogeneous elliptic operator which fulfills a very simple convexity assumption satisfies a Brunn-Minkowski type inequality on the class of open bounded sets in $\mathbb{R}^n$ satisfying a ... More

Embeddings of Line-grassmannians of Polar Spaces in Grassmann VarietiesMar 22 2013An embedding of a point-line geometry \Gamma is usually defined as an injective mapping \epsilon from the point-set of \Gamma to the set of points of a projective space such that \epsilon(l) is a projective line for every line l of \Gamma, but different ... More