“Miniaturized” Linearizations for Quadratic 0/1 Problems

In order to solve a quadratic 0/1 problem, some techniques, consisting in deriving a linear integer formulation, are used. Those techniques, called “linearization”, usually involve a huge number of additional variables. As a consequence, the exact resolution of the linear model is, in general, very difficult. Our aim, in this paper, is to propose “economical” linear models. Starting from an existing linearization (typically the so-called “classical linearization”), we find a new linearization with fewer variables. The resulting model is called “Miniaturized” linearization. Based on this approach, we propose a new linearization scheme for which numerical tests have been performed.     

Classical analogue of a quantum Schwarzschild black hole: “Standard model” and beyond

We build a model in which the main global properties of classical and semiclassical black holes become local: these are the event horizon, “no-hair,” temperature, and entropy. Our construction is based on the features of a quantum collapse, discovered when studying some particular quantum black hole models. But our model is purely classical, and this allows using the Einstein equations and classical (local) thermodynamics self-consistently and, in particular, solving the “puzzle of log 3.”     

Pseudodifferential operators of infinite order and Gevrey classes

Summary A class of pseufodifferential operators of infinite order acting on spaces of Gevrey functions and their duals is defined. For the corresponding symbols the rules of the classical symbolic calculus are proved. In particular for operators satisfying an “hipoellipticity condition” a result of propagation of Gevrey regularity, is obtained by proving the existence of a parametrix.

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Riassunto Viene definita una classe di operatori pseudodifferenziali di ordine infinito che agiscono su spazi di funzioni Gevrey e sui loro duali. Per i corrispondenti simboli si provano le regole del calcolo simbolico classico. In particolare per gli operatori che soddisfano una “condizione di ipoellitticità” si ottiene un risultato di propapagazione di regolarità Gevrey, provando l'esistenza di una parametrice.

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Work supported by Ministero della Pubblica Istruzione and G.N.A.F.A. C.N.R., of Italy.     

Functional classical mechanics and rational numbers

The notion of microscopic state of the system at a given moment of time as a point in the phase space as well as a notion of trajectory is widely used in classical mechanics. However, it does not have an immediate physical meaning, since arbitrary real numbers are unobservable. This notion leads to the known paradoxes, such as the irreversibility problem. A “functional” formulation of classical mechanics is suggested. The physical meaning is attached in this formulation not to an individual trajectory but only to a “beam” of trajectories, or the distribution function on phase space. The fundamental equation of the microscopic dynamics in the functional approach is not the Newton equation but the Liouville equation for the distribution function of the single particle. The Newton equation in this approach appears as an approximate equation describing the dynamics of the average values and there are corrections to the Newton trajectories. We give a construction of probability density function starting from the directly observable quantities, i.e., the results of measurements, which are rational numbers.     

Computational efficiency and approximate inertial manifolds for a Bénard convection system

Summary A computational comparison between classical Galerkin and approximate inertial manifold (AIM) methods is performed for the case of two-dimensional natural convection in a saturated porous material. For prediction of Hopf and torus bifurcations far from convection onset, the improvements of the AIM method over the classical one are small or negligible. Two reasons are given for the lack of distinct improvement. First, the small boundary layer length scale is the source of the instabilities, so it cannot be modeled as a “slave” to the larger scales, as the AIM attempts to do. Second, estimates based on the Gevrey class regularity of solutions to the governing equations show that the classical and AIM methods may be virtually equivalent. It is argued that these two reasons are physical and mathematical reflections of one another.     

The Expected loss in the discretization of multistage stochastic programming problems—estimation and convergence rate

In the present paper, the approximate computation of a multistage stochastic programming problem (MSSPP) is studied. First, the MSSPP and its discretization are defined. Second, the expected loss caused by the usage of the “approximate” solution instead of the “exact” one is studied. Third, new results concerning approximate computation of expectations are presented. Finally, the main results of the paper—an upper bound of the expected loss and an estimate of the convergence rate of the expected loss—are stated.     

Boundary trace inequalities and rearrangements

A new approach to boundary trace inequalities for Sobolev functions is presented, which reduces any trace inequality involving general rearrangement-invariant norms to an equivalent, considerably simpler, one-dimensional inequality for a Hardy-type operator. In particular, improvements of classical boundary trace embeddings and new optimal trace embeddings are derived. This research was partially supported by the Italian research project “Geometric properties of solutions to variational problems” of GNAMPA (INdAM) 2006, by the research project MSM 0021620839 of the Czech Ministry of Education, by grants 201/03/0935, 201/05/2033 and 201/07/0388 of the Grant Agency of the Czech Republic and by the Nečas Center for Mathematical Modeling project no. LC06052 financed by the Czech Ministry of Education.     

“Grandi” lenti in un reticolo di rette

A buffon problem is studied for a “thin lens” in the plane, a convex test body made by the union of two circular segments both less than or equal to a semicircle. The case in which the lens is “small” compared with the distance between the parallel lines of the Buffon lattice has been treated in [4]. The instance investigated in this paper is the one of a “large” lens, i.e. of a lens which can have multiple intersections with the Buffon lattice.

Lavoro eseguito col contributo parziale del M.U.R.S.T.     

Two faces of mathematics lessons in Korea: conventional lessons and innovative lessons

This study identifies the characteristics of mathematics classrooms in Korea. First, conventional Korean mathematics lessons are analyzed from the perspective of “theory of variation”. Second, an innovative lesson for gifted children is reported in detail and analyzed from the perspective of “Lakatos’ proofs and refutations”. Third, the classroom characteristics identified in both the conventional lessons and the innovative lesson are interpreted in terms of the underlying cultural values that they share with other East Asian countries. The study concludes that although the two faces of Korean mathematics lessons look different, they may flow from the same “heart”—that of the common Confucian heritage culture culture, and in particular East Asian pragmatism.     

Harnack and HWI inequalities on infinite-dimensional spaces

In this paper, the dimensional-free Harnack inequalities are established on infinite-dimensional spaces. More precisely, we establish Harnack inequalities for heat semigroup on based loop group and for Ornstein-Uhlenbeck semigroup on the abstract Wiener space. As an application, we establish the HWI inequality on the abstract Wiener space, which contains three important quantities in one inequality, the relative entropy “H”, Wasserstein distance “W”, and Fisher information “I”.     

The Deregulated Electricity Market Viewed as a Bilevel Programming Problem

In this paper, we present a bilevel programming formulation of a deregulated electricity market. By examining the electricity market in this format, we achieve two things. First, the relation of the deregulated electricity market to general economic models that can be formulated as bilevel programming problems (e.g. Stackelberg leader-follower games and principal-agency models) becomes clear. Secondly, it provides an explanation of the reason why the so-called “folk theorems” can be proven to be false for electricity networks. The interpretation of the deregulated electricity market as a bilevel program also indicates the magnitude of the error that can be made if the electricity market model studied does not take into account the physical constraints of the electric grid, or oversimplifies the electricity network to a radial network.     

A Multi-Class Dynamic User Equilibrium Model for Queuing Networks with Advanced Traveler Information Systems

This paper presents a formulation and solution algorithm for a composite dynamic user-equilibrium assignment problem with multi-user classes, in order to assess the impacts of Advanced Traveler Information Systems (ATIS) in general networks with queues. Suppose that users equipped with ATIS will receive complete information and hence be able to choose the best departure times and routes in a deterministic manner, while users not equipped with ATIS will have incomplete information and hence may make decisions on departure times and routes in a stochastic manner. This paper proposes a discrete-time, finite-dimensional variational inequality formulation that involves two criteria regarding the route and departure time choice behaviors, i.e., the deterministic dynamic user equilibrium and the nested logit-based stochastic dynamic user equilibrium. The formulation is then converted to an equivalent “zero-extreme value” minimization problem. A heuristic algorithm based on route/time-swapping process is proposed, which iteratively adjusts the route and departure time choices to reach closely to an extreme point of the minimization problem. A numerical example is used to demonstrate the effectiveness of the proposed approach for assessing the ATIS impacts such as changes in individual travel costs, departure times, route inflows, queuing peaks and total network travel cost. This revised version was published online in July 2006 with corrections to the Cover Date.     

Convex programming with single separable constraint and bounded variables

In this paper a minimization problem with convex objective function subject to a separable convex inequality constraint “≤” and bounded variables (box constraints) is considered. We propose an iterative algorithm for solving this problem based on line search and convergence of this algorithm is proved. At each iteration, a separable convex programming problem with the same constraint set is solved using Karush-Kuhn-Tucker conditions. Convex minimization problems subject to linear equality/ linear inequality “≥” constraint and bounds on the variables are also considered. Numerical illustration is included in support of theory.     

V. A. Fock and N. N. Bogoliubov and their role in establishing modern quantum field theory

The relation between the Wightman axioms in quantum field theory and the “S-matrix” Bogoliubov axioms is discussed. The choice of the Fock representation of the canonical commutation relations for asymptotic field variables is interpreted as a condition for the correct formulation of the relativistic scattering problem. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 120, No. 3, pp. 380–393, September, 1999.     

A Probabilistic Approach to Carne’s Bound

Carne’s bound is a sharp inequality controlling the transition probabilities for a discrete reversible Markov chain (Section 1). Its ordinary proof uses spectral techniques which look as efficient as miraculous. Here we present a new proof, comparing a “drift” for ways “out” and “back”, to get the gaussian part of the bound (Section 2), and using a conditioning technique to get the flight factor (Section 4). Moreover we show how our proof is more “supple” than Carne’s one and may generalize (Section 3.2).      

The Incoherence Objection in Moral Theory

J.J.C. Smart famously complained that rule utilitarianism is incoherent, and that rule utilitarians are guilty of “rule worship”. Much has been said about whether Smart’s complaint is justified, but I will assume for the sake of argument that Smart was on to something. Instead, I have three other goals. First, I want to show that Smart’s complaint is a specific instance of a more general objection to a moral theory—what I will call the Incoherence Objection. Second, I want to illustrate how the Incoherence Objection can apply both to consequentialist and, surprisingly, some nonconsequentialist theories. Finally, I want to demonstrate at least one way nonconsequentialist theories that make use of rules, principles, and the like can dodge the Incoherence Objection.     

Algebraic axiomatization of tense intuitionistic logic

We introduce two unary operators G and H on a relatively pseudocomplemented lattice which form an algebraic axiomatization of the tense quantifiers “it is always going to be the case that” and “it has always been the case that”. Their axiomatization is an extended version for the classical logic and it is in accordance with these operators on many-valued Łukasiewicz logic. Finally, we get a general construction of these tense operators on complete relatively pseudocomplemented lattice which is a power lattice via the so-called frame.     

The Grand Riemann Hypothesis

These lectures are a continuation of Bombieri’s series “The classical Theory of Zeta and L-Functions” (in this volume). Naturally there is some overlap between his and our presentations. My aim is to formulate the Riemann Hypothesis “GRH” in its most general setting and to demonstrate its importance and power as well as to indicate some of the progress that has been made around these conjectures. A particular theme being that a number of the striking applications of the GRH have been proven unconditionally by establishing suitably strong approximations thereof.     

On Hausdorff measure and an inequality due to Maz’ya

We give an “elementary” proof of an inequality due to Maz’ya. As a prerequisite we prove an approximation property for the Hausdorff measure. We also comment on the relations between Maz’ya’s inequality, the isoperimetric inequality, and the Sobolev inequality.