Results for "Matteo Bonforte"

total 3821took 0.10s
Quantitative a Priori Estimates for Fast Diffusion Equations with Caffarelli-Kohn-Nirenberg weights. Harnack inequalities and Hölder continuityApr 10 2018Oct 29 2018We study a priori estimates for a class of non-negative local weak solution to the weighted fast diffusion equation $u_t = |x|^{\gamma} \nabla\cdot (|x|^{-\beta} \nabla u^m)$, with $0 < m <1$ posed on cylinders of $(0,T)\times{\mathbb R}^N$. The weights ... More
Non-existence and instantaneous extinction of solutions for singular nonlinear fractional diffusion equationsMay 12 2015We show non-existence of solutions of the Cauchy problem in $\mathbb{R}^N$ for the nonlinear parabolic equation involving fractional diffusion $\partial_t u + (-\Delta)^s \phi(u)= 0,$ with $0<s<1$ and very singular nonlinearities $\phi$ . More precisely, ... More
Sharp global estimates for local and nonlocal porous medium-type equations in bounded domainsOct 31 2016Nov 25 2017This paper provides a quantitative study of nonnegative solutions to nonlinear diffusion equations of porous medium-type of the form $\partial_t u + {\mathcal L}u^m=0$, $m>1$, where the operator ${\mathcal L}$ belongs to a general class of linear operators, ... More
Sharp Extinction Rates for Fast Diffusion Equations on Generic Bounded DomainsFeb 08 2019We investigate the homogeneous Dirichlet problem for the Fast Diffusion Equation $u_t=\Delta u^m$, posed in a smooth bounded domain $\Omega\subset \mathbb{R}^N$, in the exponent range $m_s=(N-2)_+/(N+2)<m<1$. It is known that bounded positive solutions ... More
Total Variation Flow and Sign Fast Diffusion in one dimensionJul 11 2011Aug 17 2011We consider the dynamics of the Total Variation Flow (TVF) $u_t=\div(Du/|Du|)$ and of the Sign Fast Diffusion Equation (SFDE) $u_t=\Delta\sign(u)$ in one spatial dimension. We find the explicit dynamic and sharp asymptotic behaviour for the TVF, and we ... More
A Priori Estimates for Fractional Nonlinear Degenerate Diffusion Equations on bounded domainsNov 27 2013We investigate quantitative properties of the nonnegative solutions $u(t,x)\ge 0$ to the nonlinear fractional diffusion equation, $\partial_t u + {\mathcal L} (u^m)=0$, posed in a bounded domain, $x\in\Omega\subset {\mathbb R}^N$ with $m>1$ for $t>0$. ... More
Fractional Nonlinear Degenerate Diffusion Equations on Bounded Domains Part I. Existence, Uniqueness and Upper BoundsAug 31 2015Sep 30 2015We investigate quantitative properties of nonnegative solutions $u(t,x)\ge 0$ to the nonlinear fractional diffusion equation, $\partial_t u + \mathcal{L}F(u)=0$ posed in a bounded domain, $x\in\Omega\subset \mathbb{R}^N$, with appropriate homogeneous ... More
Quantitative Local and Global A Priori Estimates for Fractional Nonlinear Diffusion EquationsOct 09 2012Oct 07 2013We establish quantitative estimates for solutions $u(t,x)$ to the fractional nonlinear diffusion equation, $\partial_t u +(-\Delta)^s (u^m)=0$ in the whole range of exponents $m>0$, $0<s<1$. The equation is posed in the whole space $x\in\mathbb{R}^d$. ... More
Positivity, local smoothing, and Harnack inequalities for very fast diffusion equationsMay 30 2008Dec 01 2008We investigate qualitative properties of local solutions $u(t,x)\ge 0$ to the fast diffusion equation, $\partial_t u =\Delta (u^m)/m$ with $m<1$, corresponding to general nonnegative initial data. Our main results are quantitative positivity and boundedness ... More
Sharp global estimates for local and nonlocal porous medium-type equations in bounded domainsOct 31 2016This paper provides a quantitative study of nonnegative solutions to nonlinear diffusion equations of porous medium-type of the form $\partial_t u + \mathcal{L} u^m=0$, $m>1$, where the operator $\mathcal{L}$ belongs to a general class of linear operators, ... More
Special fast diffusion with slow asymptotics. Entropy method and flow on a Riemannian manifoldMay 30 2008May 27 2009We consider the asymptotic behaviour of positive solutions $u(t,x)$ of the fast diffusion equation $u_t=\Delta (u^{m}/m)={\rm div} (u^{m-1}\nabla u)$ posed for $x\in\RR^d$, $t>0$, with a precise value for the exponent $m=(d-4)/(d-2)$. The space dimension ... More
Sharp boundary behaviour of solutions to semilinear nonlocal elliptic equationsOct 07 2017Feb 12 2018We investigate quantitative properties of nonnegative solutions $u(x)\ge 0$ to the semilinear diffusion equation $\mathcal{L} u= f(u)$, posed in a bounded domain $\Omega\subset {\mathbb R}^N$ with appropriate homogeneous Dirichlet or outer boundary conditions. ... More
Behaviour near extinction for the Fast Diffusion Equation on bounded domainsDec 03 2010We consider the Fast Diffusion Equation $u_t=\Delta u^m$ posed in a bounded smooth domain $\Omega\subset \RR^d$ with homogeneous Dirichlet conditions; the exponent range is $m_s=(d-2)_+/(d+2)<m<1$. It is known that bounded positive solutions $u(t,x)$ ... More
Infinite speed of propagation and regularity of solutions to the fractional porous medium equation in general domainsOct 13 2015Jun 21 2016We study the positivity and regularity of solutions to the fractional porous medium equations $u_t+(-\Delta)^su^m=0$ in $(0,\infty)\times\Omega$, for $m>1$ and $s\in (0,1)$ and with Dirichlet boundary data $u=0$ in $(0,\infty)\times({\mathbb R}^N\setminus\Omega)$, ... More
Existence, Uniqueness and Asymptotic behaviour for fractional porous medium equations on bounded domainsApr 24 2014Jul 24 2014We consider nonlinear diffusive evolution equations posed on bounded space domains, governed by fractional Laplace-type operators, and involving porous medium type nonlinearities. We establish existence and uniqueness results in a suitable class of solutions ... More
Optimal Existence and Uniqueness Theory for the Fractional Heat EquationJun 02 2016Aug 29 2016We construct a theory of existence, uniqueness and regularity of solutions for the fractional heat equation $\partial_t u +(-\Delta)^s u=0$, $0<s<1$, posed in the whole space $\mathbb{R}^N$ with data in a class of locally bounded Radon measures that are ... More
Quantitative Local Bounds for Subcritical Semilinear Elliptic EquationsJan 27 2012The purpose of this paper is to prove local upper and lower bounds for weak solutions of semilinear elliptic equations of the form $-\Delta u= c u^p$, with $0<p<p_s=(d+2)/(d-2)$, defined on bounded domains of $\RR^d$, $d\ge 3$, without reference to the ... More
Weighted fast diffusion equations (Part I): Sharp asymptotic rates without symmetry and symmetry breaking in Caffarelli-Kohn-Nirenberg inequalitiesFeb 26 2016Jun 20 2016In this paper we consider a family of Caffarelli-Kohn-Nirenberg interpolation inequalities (CKN), with two radial power law weights and exponents in a subcritical range. We address the question of symmetry breaking: are the optimal functions radially ... More
Weighted fast diffusion equations (Part II): Sharp asymptotic rates of convergence in relative error by entropy methodsFeb 26 2016Jun 20 2016This paper is the second part of the study. In Part~I, self-similar solutions of a weighted fast diffusion equation (WFD) were related to optimal functions in a family of subcritical Caffarelli-Kohn-Nirenberg inequalities (CKN) applied to radially symmetric ... More
Classification of radial solutions to the Emden-Fowler equation on the hyperbolic spaceApr 19 2011May 01 2011We study the Emden-Fowler equation $-\Delta u=|u|^{p-1}u$ on the hyperbolic space ${\mathbb H}^n$. We are interested in radial solutions, namely solutions depending only on the geodesic distance from a given point. The critical exponent for such equation ... More
Sharp rates of decay of solutions to the nonlinear fast diffusion equation via functional inequalitiesJul 17 2009The goal of this note is to state the optimal decay rate for solutions of the nonlinear fast diffusion equation and, in self-similar variables, the optimal convergence rates to Barenblatt self-similar profiles and their generalizations. It relies on the ... More
Asymptotics of the fast diffusion equation via entropy estimatesApr 18 2007We consider non-negative solutions of the fast diffusion equation $u_t=\Delta u^m$ with $m \in (0,1)$, in the Euclidean space R^d, d?3, and study the asymptotic behavior of a natural class of solutions, in the limit corresponding to $t\to\infty$ for $m\ge ... More
Clustering dynamics in a class of normalised generalised gamma dependent priorsAug 02 2016Normalised generalised gamma processes are random probability measures that induce nonparametric prior distributions widely used in Bayesian statistics, particularly for mixture modelling. We construct a class of dependent normalised generalised gamma ... More
Clustering dynamics in a class of normalised generalised gamma dependent priorsAug 02 2016Nov 04 2016Normalised generalised gamma processes are random probability measures that induce nonparametric prior distributions widely used in Bayesian statistics, particularly for mixture modelling. We construct a class of dependent normalised generalised gamma ... More
Common factors, trends, and cycles in large datasetsSep 05 2017Nov 07 2017This paper considers a non-stationary dynamic factor model for large datasets to disentangle long-run from short-run co-movements. We first propose a new Quasi Maximum Likelihood estimator of the model based on the Kalman Smoother and the Expectation ... More
Some insights on bicategories of fractions: representations and compositions of 2-morphismsOct 15 2014Apr 20 2016In this paper we investigate the construction of bicategories of fractions originally described by D. Pronk: given any bicategory $\mathcal{C}$ together with a suitable class of morphisms $\mathbf{W}$, one can construct a bicategory $\mathcal{C}[\mathbf{W}^{-1}]$, ... More
Chemically-exfoliated single-layer MoS$_2$ : stability, lattice dynamics and catalytic adsorption from first principlesDec 05 2013Chemically and mechanically exfoliated MoS$_2$ single-layer samples have substantially different properties. While mechanically exfoliated single-layers are mono-phase (1H polytype with Mo in trigonal prismatic coordination), the chemically exfoliated ... More
Cosmology with the lyman-alpha forest in the WMAP eraOct 15 2003In the WMAP era of high precision cosmology an accurate determination of the matter power spectrum from lyman-alpha forest data becomes crucial. When combining the matter power spectrum derived from CMB experiments with that inferred from lyman-alpha ... More
The coherent interaction between matter and radiation - A tutorial on the Jaynes-Cummings modelNov 04 2011The Jaynes-Cummings (JC) model is a milestone in the theory of coherent interaction between a two-level system and a single bosonic field mode. This tutorial aims to give a complete description of the model, analyzing the Hamiltonian of the system, its ... More
On the strong coupling expansion in the su(1|1) sector of N=4 SYMMay 08 2008May 12 2008We consider the anomalous dimension of the fermionic highest states Tr(psi^L) in the su(1|1) sector of N=4 SYM at strong coupling. In the thermodynamical L->OO limit it is described by a BES-like integral equation recently proposed by Rej, Staudacher ... More
Universality of three gaugino anomalous dimensions in N=4 SYMMay 04 2007May 05 2007We study maximal helicity three gaugino operators in N=4 Super Yang-Mills theory. We show that the lowest anomalous dimension of scaling operators with generic finite spin can be expressed in terms of the universal anomalous dimension appearing at twist-2. ... More
Anomalous dimensions at twist-3 in the sl(2) sector of N=4 SYMApr 26 2007We consider twist-3 operators in the sl(2) sector of N=4 SYM built out of three scalar fields with derivatives. We extract from the Bethe Ansatz equations of this sector the exact lowest anomalous dimension gamma(s) of scaling fields for several values ... More
Wave functions for Hamiltonian Lattice Gauge TheoryMar 21 2000We study four dimensional SU(2) lattice gauge theory in the Hamiltonian formalism by Green's Function Monte Carlo methods. A trial ground state wave function is introduced to improve the configuration sampling and we discuss the interplay between its ... More
Verification of Reachability Problems for Time Basic Petri NetsSep 09 2014Time-Basic Petri nets, is a powerful formalism for model- ing real-time systems where time constraints are expressed through time functions of marking's time description associated with transition, representing possible firing times. We introduce a technique ... More
Ultraluminous X-ray sources: three exciting yearsOct 19 2015The extreme extragalactic sources known as Ultraluminous X-ray Sources (ULX) represent a unique testing environment for compact objects population studies and the accretion process. Their nature has long been disputed. Their luminosity, well above the ... More
On the classification of complete area-stationary and stable surfaces in the sub-Riemannian Sol manifoldMay 25 2013Aug 17 2013We study the classification of area-stationary and stable $C^2$ regular surfaces in the space of the rigid motions of the Minkowski plane E(1,1), equipped with its sub-Riemannian structure. We construct examples of area-stationary surfaces that are not ... More
Hadronic Production of Heavy QuarksOct 29 1997We review the status of theoretical evaluations of heavy quark and heavy quarkonium hadroproduction cross sections and their comparisons with experimental data.
Jet Areas, and What They are Good ForJun 19 2007We introduce the concept of the area of a jet, and show how it can be used to perform the subtraction of even a large amount of diffuse noise from hard jets.
pQCD Calculations of Heavy Quark and J/psi ProductionFeb 20 2007We review the present status of theoretical predictions for both closed (J/psi) and open heavy quark production in high energy collisions, and their comparisons to experimental data.
QCD Predictions for Charm and Bottom Production at RHICDec 20 2005We present up-to-date QCD predictions for open charm and bottom production at RHIC in nucleon-nucleon collisions at \sqrt{S} = 200 GeV. The electron spectrum resulting from heavy flavor decays is also evaluated for direct comparison to the PHENIX and ... More
Rise and Fall of the Bottom Quark Production ExcessJul 16 2004We review the history of comparisons between bottom production measurements and QCD predictions. We challenge the existence of a `significant discrepancy', and argue that standard approaches to QCD calculations do a good job in describing the experimental ... More
An equilibrated fluxes approach to the Certified Descent Algorithm for shape optimization using conforming Finite Element and Discontinuous Galerkin discretizationsNov 10 2016The Certified Descent Algorithm (CDA) is a gradient-based method for shape optimization which certifies that the direction computed using the shape gradient is a genuine descent direction for the objective functional under analysis. It relies on the computation ... More
Contracting rigid germs in higher dimensionsSep 30 2011Jan 09 2013Following Favre, we define a holomorphic germ f:(C^d,0) -> (C^d,0) to be rigid if the union of the critical set of all iterates has simple normal crossing singularities. We give a partial classification of contracting rigid germs in arbitrary dimensions ... More
A Poincaré-Dulac renormalization theorem for attracting rigid germs in $\mathbb{C}^d$Mar 14 2011Sep 30 2011Studying the dynamics of attracting rigid germs $f:(\mathbb{C}^d, 0) \rightarrow (\mathbb{C}^d, 0)$ in dimension $d \geq 3$, a new phenomenon arise: principal resonances. The resonances of the classic Poincar\'e-Dulac theory are given by (multiplicative) ... More
Gravity, holography and applications to condensed matterOct 09 2016Oct 17 2016Momentum relaxation is an ever-present and unavoidable ingredient of any realistic condensed matter system. In real-world materials the presence of a lattice, impurities or disorder forces momentum to dissipate and leads to relevant physical effects such ... More
Stress-corrosion mechanisms in silicate glassesJan 19 2009Apr 01 2009The present review is intended to revisit the advances and debates in the comprehension of the mechanisms of subcritical crack propagation in silicate glasses almost a century after its initial developments. Glass has inspired the initial insights of ... More
Localisation in 2+1 dimensional SU(3) pure gauge theory at finite temperatureMar 12 2019I study the localisation properties of low Dirac eigenmodes in 2+1 dimensional SU(3) pure gauge theory, both in the low-temperature, confined and chirally-broken phase and in the high-temperature, deconfined and chirally-restored phase, by means of numerical ... More
Radial and cylindrical symmetry of solutions to the Cahn-Hilliard equationFeb 01 2019The paper is devoted to the classification of entire solutions to the Cahn-Hilliard equation $-\Delta u = u-u^3-\delta$ in $\R^N$, with particular interest in those solutions whose nodal set is either bounded or contained in a cylinder. The aim is to ... More
Lyapunov exponents, holomorphic flat bundles and de Rham moduli spaceOct 30 2018We consider Lyapunov exponents for flat bundles over hyperbolic curves defined via parallel transport over the geodesic flow. We refine a lower bound obtained by Eskin, Kontsevich, Moeller and Zorich showing that the sum of the first k exponents is greater ... More
Top production at large p_t at NLO+NLL accuracySep 18 2018We introduce a new version of the FONLL code, now capable of calculating differential distributions for top quark production with next-to-leading-log resummation of log(p_t/m) terms. Numerical results for LHC and FCC kinematics are presented. In the transverse ... More
Thermodynamic laws for populations and quantum coherence: A self-contained introduction to the resource theory approach to thermodynamicsJul 30 2018In these notes I give a self-contained introduction to the resource theory approach to quantum thermodynamics. I will introduce in an elementary manner the technical machinery necessary to unpack and prove the core statements of the theory. The topics ... More
On a homotopy version of the Duflo isomorphismDec 19 2017For a finite dimensional Lie algebra $\mathfrak{g}$, the Duflo map $S\mathfrak{g}\rightarrow U\mathfrak{g}$ defines an isomorphism of $\mathfrak{g}$-modules. On $\mathfrak{g}$-invariant elements it gives an isomorphism of algebras. Moreover, it induces ... More
Thermal properties of a string bit model at large NSep 06 2017We study the finite temperature properties of a recently introduced string bit model designed to capture some features of the emergent string in the tensionless limit. The model consists of a pair of bosonic and fermionic bit operators transforming in ... More
Filtrations on graph complexes and the Grothendieck-Teichmüller Lie algebra in depth twoJul 03 2017We establish an isomorphism between the Grothendieck-Teichm\"uller Lie algebra $\mathfrak{grt}_1$ in depth two modulo higher depth and the cohomology of the two-loop part of the graph complex of internally connected graphs $\mathsf{ICG}(1)$. In particular, ... More
A bicategory of reduced orbifolds from the point of view of differential geometry - IApr 25 2013Jan 09 2015We describe a bicategory $(\mathcal{R}ed\,\mathcal{O}rb)$ of reduced orbifolds in the framework of classical differential geometry (i.e. without any explicit reference to notions of Lie groupoids or differentiable stacks, but only using orbifold atlases, ... More
The classification of isotrivially fibred surfaces with p_g=q=2Apr 08 2009Jul 29 2010An isotrivially fibred surface is a smooth projective surface endowed with a morphism onto a curve such that all the smooth fibres are isomorphic to each other. The first goal of this paper is to classify the isotrivially fibred surfaces with $p_g=q=2$ ... More
A Law of Large Numbers for an Interacting Particle System with Confining PotentialJan 03 2007In this paper we consider an interacting particle system modeled as a system of $N$ stochastic differential equations driven by Brownian motions with a drift term including a confining potential acting on each particle, and an interaction potential modeling ... More
Finite generation of iterated wreath products in product actionMay 30 2015Jun 21 2015Let $\mathcal{S}$ be a sequence of finite perfect transitive permutation groups with uniformly bounded number of generators. We prove that the infinitely iterated wreath product in product action of the groups in $\mathcal{S}$ is topologically finitely ... More
Interior regularity of solutions of non-local equations in Sobolev and Nikol'skii spacesJan 12 2016We prove interior $H^{2s-\varepsilon}$ regularity for weak solutions of linear elliptic integro-differential equations close to the fractional $s$-Laplacian. The result is obtained via intermediate estimates in Nikol'skii spaces, which are in turn carried ... More
Combinatorially two-orbit convex polytopesNov 06 2014Feb 19 2015Any convex polytope whose combinatorial automorphism group has two orbits on the flags is isomorphic to one whose group of Euclidean symmetries has two orbits on the flags (equivalently, to one whose automorphism group and symmetry group coincide.) Hence, ... More
The fractional Laplacian in power-weighted $L^p$ spaces: integration-by-parts formulas and self-adjointnessDec 05 2015Aug 08 2016We consider the fractional Laplacian operator $(-\Delta)^s$ (let $ s \in (0,1) $) on Euclidean space and investigate the validity of the classical integration-by-parts formula that connects the $ L^2(\mathbb{R}^d) $ scalar product between a function and ... More
Proof diagrams for multiplicative linear logicJun 29 2016Sep 14 2016The original idea of proof nets can be formulated by means of interaction nets syntax. Additional machinery as switching, jumps and graph connectivity is needed in order to ensure correspondence between a proof structure and a correct proof in sequent ... More
Weak fiber products in a bicategory of fractionsDec 10 2014We fix any pair $(\mathbf{\mathscr{C}},\mathbf{W})$ consisting of a bicategory and a class of morphisms in it, admitting a bicalculus of fractions, i.e. a "localization" of $\mathbf{\mathscr{C}}$ with respect to the class $\mathbf{W}$. In the resulting ... More
Automatic Synthesis of Test Cases to Identify Software RedundancyNov 16 2014Software system can include redundant implementation elements, such as, different methods that can produce indistinguishable results. This type of redundancy is called intrinsic if it is already available in the software, although not intentionally planned. ... More
Minimum relative entropy distributions with a large mean are GaussianMay 26 2016We consider the following frustrated optimization problem: given a prior probability distribution $q$, find the distribution $p$ minimizing the relative entropy with respect to $q$ such that $\textrm{mean}(p)$ is fixed and large. We show that solutions ... More
On the large $Ω$-deformations in the Nekrasov-Shatashvili limit of $\mathcal N=2^{*}$ SYMApr 30 2016May 14 2016We study the multi-instanton partition functions of the $\Omega$-deformed $\mathcal N =2^{*}$ $SU(2) $ gauge theory in the Nekrasov-Shatashvili (NS) limit. They depend on the deformation parameters $\epsilon_{1}$, the scalar field expectation value $a$, ... More
An Improved Upper Bound for the Ground State Energy of Fermion Lattice ModelsMay 23 2001We present an improved upper bound for the ground state energy of lattice fermion models with sign problem. The bound can be computed by numerical simulation of a recently proposed family of deformed Hamiltonians with no sign problem. For one dimensional ... More
The Lyman-alpha forest as a probe of fundamental physicsApr 28 2005We use LUQAS, a sample of 27 high resolution high signal-to-noise UVES quasar (QSO) spectra (Kim et al. 2004), and the Croft et al. (2002) sample together with a set of high resolution large box size hydro-dynamical simulations run with the code GADGET-II ... More
Elementary Thermal Operations and the Universality of Thermodynamic ConstraintsJul 01 2016To what extent is the resource theory approach to thermodynamics relevant for realistic experimental scenarios? We deconstruct this framework, showing that each transition among incoherent states allowed in the theory can be obtained by sequentially applying ... More
On high dimensional directed polymer in random mediaMay 16 1995Aug 10 1995Directed polymers in random media are studied using results of the asymptotic theory of extreme statistics. Despite the strong correlation, one can recover the behavior of independent random variables for high dimensions, using a result which requires ... More
On Heavy Quarks Photoproduction and c -> D* Fragmentation FunctionsAug 07 1997The state of the art of the theoretical calculations for heavy quarks photoproduction is reviewed. The full fixed order next-to-leading order massive calculation and the resummation of large log(p_T/m) terms for differential cross sections are described. ... More
Heavy Quark Production: Theory vs. ExperimentDec 15 2003The current status of the comparisons between some experimental results and theoretical predictions for heavy quark production is reviewed. It is shown that the combination of new theoretical tools and better experimental input allows for a good description ... More
Phenomenology of quarkonia production in fixed target experiments and at the Tevatron and HERA collidersJun 16 1997The phenomenology of heavy quarkonia production in fixed target experiments and at the Tevatron and HERA colliders is reviewed. The latest theoretical results are presented and compared with data, with emphasis on the predictions of the factorization ... More
Search for new physics in dijet final states in ATLAS and CMSSep 14 2017Events containing a pair of high energy hadronic jet can provide clear signatures in the search for new physics at high energy hadron colliders. The ATLAS and CMS experiments collected the data from LHC collisions at $\sqrt{s}$= 13 TeV during 2015 and ... More
Double scaling limit of N=2 chiral correlators with Maldacena-Wilson loopOct 24 2018We consider $\mathcal N=2$ conformal QCD in four dimensions and the one-point correlator of a class of chiral primaries with the circular $\frac{1}{2}$-BPS Maldacena-Wilson loop. We analyze a recently introduced double scaling limit where the gauge coupling ... More
Explicit bounds on exceptional zeroes of Dirichlet $L$-functionsSep 14 2018The aim of this paper is to improve the upper bound for the exceptional zeroes $\beta_0$ of Dirichlet $L$-functions. We do this by improving on explicit estimate for $L'(\sigma, \chi)$ for $\sigma$ close to unity.
Følner functions and the generic Word Problem for finitely generated amenable groupsMar 12 2017Jul 03 2018We introduce and investigate different definitions of effective amenability, in terms of computability of F{\o}lner sets, Reiter functions, and F{\o}lner functions. As a consequence, we prove that recursively presented amenable groups have subrecursive ... More
Arbitrage and Hedging in model-independent markets with frictionsDec 04 2015Aug 25 2016We provide a Fundamental Theorem of Asset Pricing and a Superhedging Theorem for a model independent discrete time financial market with proportional transaction costs. We consider a probability-free version of the Robust No Arbitrage condition introduced ... More
A family of covering properties for forcing axioms and strongly compact cardinalsMar 03 2007This paper presents the main results in my Ph.D. thesis. In what follows several proofs of SCH are presented introducing a family of covering properties which implies both SCH and the failure of various forms of square. These covering properties are also ... More
Guessing models and generalized Laver diamondDec 10 2010Oct 10 2011We analyze the notion of guessing model, a way to assign combinatorial properties to arbitrary regular cardinals. Guessing models can be used, in combination with inaccessibility, to characterize various large cardinals axioms, ranging from supercompactness ... More
Dispersive deformations of the Hamiltonian structure of Euler's equationsSep 01 2015Euler's equations for a two-dimensional system can be written in Hamiltonian form, where the Poisson bracket is the Lie-Poisson bracket associated to the Lie algebra of divergence free vector fields. We show how to derive the Poisson brackets of 2d hydrodynamics ... More
F-thresholds, integral closure and convexityJul 05 2016The purpose of this note is to revisit the results of arXiv:1407.4324 from a slightly different perspective, outlining how, if the integral closures of a finite set of prime ideals abide the expected convexity patterns, then the existence of a peculiar ... More
Two-orbit convex polytopes and tilingsMar 10 2014We classify the convex polytopes whose symmetry groups have two orbits on the flags. These exist only in two or three dimensions, and the only ones whose combinatorial automorphism group is also two-orbit are the cuboctahedron, the icosidodecahedron, ... More
Fine regularity results for Mumford-Shah minimizers: porosity, higher integrability and the Mumford-Shah conjectureOct 12 2016We review some classical results and more recent insights about the regularity theory for local minimizers of the Mumford and Shah energy and their connections with the Mumford and Shah conjecture. We discuss in details the links among the latter, the ... More
On hereditarily just infinite profinite groups obtained via iterated wreath productsMay 30 2015We study a generalisation of the family of non-(virtually pro-$p$) hereditarily just infinite profinite groups introduced by J.\! S.\! Wilson in 2010. We prove that this family contains groups of finite lower rank. We also show that many groups in this ... More
Trakhtenbrot theorem and first-order axiomatic extensions of MTLMar 04 2014Jul 09 2014In 1950, B.A. Trakhtenbrot showed that the set of first-order tautologies associated to finite models is not recursively enumerable. In 1999, P. H\'ajek generalized this result to the first-order versions of \L ukasiewicz, G\"odel and Product logics. ... More
First-order Nilpotent Minimum Logics: first stepsMar 30 2011Jul 02 2012Following the lines of the analysis done in [BPZ07, BCF07] for first-order G\"odel logics, we present an analogous investigation for Nilpotent Minimum logic NM. We study decidability and reciprocal inclusion of various sets of first-order tautologies ... More
Proof Diagrams for Multiplicative Linear Logic: Syntax and SemanticsFeb 01 2017Proof nets are a syntax for linear logic proofs which gives a coarser notion of proof equivalence with respect to syntactic equality together with an intuitive geometrical representation of proofs. In this paper we give an alternative $2$-dimensional ... More
A blackbody is not a blackboxOct 27 2010Nov 08 2010We discuss carefully the blackbody approximation, stressing what it is (a limit case of radiative transfer), and what it is not (the assumption that the body is perfectly absorbing, i.e. black). Furthermore, we derive the Planck spectrum without enclosing ... More
Some insights on bicategories of fractions - IIIOct 23 2014Nov 21 2014We fix any bicategory $\mathscr{A}$ together with a class of morphisms $\mathbf{W}_{\mathscr{A}}$, such that there is a bicategory of fractions $\mathscr{A}[\mathbf{W}_{\mathscr{A}}^{-1}]$. Given another such pair $(\mathscr{B},\mathbf{W}_{\mathscr{B}})$ ... More
Can Market Risk Perception Drive Inefficient Prices? Theory and EvidenceSep 17 2014This work presents an asset pricing model that under rational expectation equilibrium perspective shows how, depending on risk aversion and noise volatility, a risky-asset has one equilibrium price that differs in term of efficiency: an informational ... More
D0-brane tension in string field theoryAug 12 2005We compute the D0-brane tension in string field theory by representing it as a tachyon lump of the D1-brane compactified on a circle of radius $R$. To this aim, we calculate the lump solution in level truncation up to level L=8. The normalized D0-brane ... More
Green Function Simulation of Hamiltonian Lattice Models with Stochastic ReconfigurationJul 20 1999Feb 07 2000We apply a recently proposed Green Function Monte Carlo to the study of Hamiltonian lattice gauge theories. This class of algorithms computes quantum vacuum expectation values by averaging over a set of suitable weighted random walkers. By means of a ... More
Bosonization and the lattice: the $d=2$ Gross-Neveu modelMar 14 1994We consider the lattice formulation of bosonized quantum field theories. As a non trivial example, we study the two dimensional Gross-Neveu model. Analytical investigations and direct numerical simulation strongly suggest that the lattice model reproduces ... More
Sudakov Expansions and Top Quark Physics at LHCJun 28 2005We review some peculiar features of Sudakov expansions in the calculation of electroweak radiative corrections in the MSSM at high energy. We give specific examples and consider in particular the process b g -> t W of single top quark production relevant ... More
Monte Carlo study of exact S-matrix duality in non simply laced affine Toda theoriesAug 02 1995Aug 03 1995The $(g_2^{(1)}, d_4^{(3)})$\ pair of non simply laced affine Toda theories is studied from the point of view of non perturbative duality. The classical spectrum of each member is composed of two massive scalar particles. The exact S-matrix prediction ... More
Diagrammatic evaluation of conformal weights in the U_q[SU(2)] symmetric Heisenberg chainJun 20 1995We consider the $U_q[SU(2)]$ symmetric Heisenberg chain when $q=e^{i\pi/(m+1)}$ and $m$ is integer. We consider the cases $m=3$ and $m=5$ which correspond to the Ising and 3-state Potts models. We study the finite size scaling (FSS) of the ground states ... More
On the classification of surfaces of general type with $p_g=q=2$Nov 22 2013The paper is an extended version of the talk which I gave at the XIX Congresso dell'UMI in Bologna in September 2011. The aim of this paper is twofold: first, to give an overview on the recent development in the classification of surfaces of general type ... More
Dissecting financial markets: Sectors and statesJul 05 2002By analyzing a large data set of daily returns with data clustering technique, we identify economic sectors as clusters of assets with a similar economic dynamics. The sector size distribution follows Zipf's law. Secondly, we find that patterns of daily ... More
Recent Progress in Jet Algorithms and Their Impact in Underlying Event StudiesJun 09 2009Recent developments in jet clustering are reviewed. We present a list of fast and infrared and collinear safe algorithms, and also describe new tools like jet areas. We show how these techniques can be applied to the study of underlying event or, more ... More