fast exact search in hamming space with multi index hashing there is growing interest in representing image data and feature descriptors using compact binary codes for fast near neighbor search although binary codes are motivated by their use as direct indices addresses into a hash table codes longer than 32 bits are not being used as such as it was thought to be ineffective we introduce a rigorous way to build multiple hash tables on binary code substrings that enables exact k nearest neighbor search in hamming space the approach is storage efficient and straight forward to implement theoretical analysis shows that the algorithm exhibits sub linear run time behavior for uniformly distributed codes empirical results show dramatic speedups over a linear scan baseline for datasets of up to one billion codes of 64 128 or 256 bits

strategic information transmission this paper develops a model of strategic communication in which a better informed sender s sends a possibly noisy signal to a receiver r who then takes an action that determines the welfare of both we characterize the set of bayesian nash equilibria under standard assumptions and show that equilibrium signaling always takes a strikingly simple form in which s partitions the support of the scalar variable that represents his private information and introduces noise into his signal by reporting in effect only which element of the partition his observation actually lies in we show under further assumptions that before s observes his private information the equilibrium whose partition has the greatest number of elements is pareto superior to all other equilibria and that if agents coordinate on this equilibrium r s equilibrium expected utility rises when agents preferences become more similar since r bases his choice of action on rational expectations this establishes a sense in which equilibrium signaling is more informative when agents preferences are more similar

some results concerning the generic continuity of set valued mappings abstract a theorem proved by fort in 1951 states that an upper semi continuous mapping from a baire space x into non empty compact subsets of a metric space is both lower and upper semi continuous at the points of a dense residual set of x in this paper we present several results concerning the generic continuity of set valued mappings first we demonstrate that generic continuity in the sense of baire category cannot be extended to almost everywhere continuity with respect to some measure then we show that baireness of the domain space is a necessary condition for fort s theorem to hold finally we show that fort s theorem holds without any compactness assumption on the images of the set valued mapping

the solution of tingley s problem for the operator norm unit sphere of complex n n matrices abstract in this paper we study geometric structures and isometries of the unit sphere of n n complex matrices we introduce the notion of proper exposed points of the unit ball of a banach space which provides a refinement of that of exposed point provided that the space is separable as a new geometric interpretation of unitary matrices it is shown that the set of all proper exposed points of the unit ball of m n c coincides with its unitary group u n where m n c denotes the algebra of all n n complex matrices moreover we show that every maximal convex subset of the unit sphere of m n c can be identified with the unit ball of m n 1 c by an affine bijection preserving the unitary matrices this map is isometric with respect to any unitarily invariant norm as an application we completely determine the forms of surjective isometries on the unit sphere of m n c with respect to the operator norm which provides an affirmative answer to tingley s problem on m n c

optimal use of communication resources we study a repeated game with asymmetric information about a dynamic state of nature in the course of the game the better informed player can communicate some or all of his information to the other our model covers costly and or bounded communication we characterize the set of equilibrium payoffs and contrast these with the communication equilibrium payoffs which by definition entail no communication costs

on the mazur ulam property for the space of hilbert space valued continuous functions abstract let k be a compact hausdorff space and let h be a real or complex hilbert space with dim h r 2 we prove that the space c k h of all h valued continuous functions on k equipped with the supremum norm satisfies the mazur ulam property that is if y is any real banach space every surjective isometry from the unit sphere of c k h onto the unit sphere of y admits a unique extension to a surjective real linear isometry from c k h onto y our strategy relies on the structure of c k module of c k h and several results in jb triple theory for this purpose we determine the facial structure of the closed unit ball of a real jb triple and its dual space

learning discriminability preserving histogram representation from unordered features for multibiometric feature fused template protection multi biometric feature level fusion exploits feature information from more than one biometric source to improve recognition performance and template security when ordered and unordered feature sets representing different biometric sources are involved feature fusion becomes problematic one way to mitigate this incompatibility problem is to transform the unordered extracted feature sets to ordered feature representation without sacrificing the discrimination power of the original features so that a feature fusion on ordered features can subsequently be applied existing unordered to ordered feature transformation methods are designed for three dimensional minutiae point sets and are mostly not adaptable to high dimensional feature input this paper proposes a feature transformation scheme to learn a histogram representation from an unordered feature set our algorithm estimates the component wise correspondences among the sample feature sets of each user and then learns a set of bins per user based on the distribution of the mutually corresponding feature instances given the learnt bins the histogram representation of a sample can be generated by concatenating the normalized frequency of unordered features falling into histogram bins experimental results on seven unimodal and three bimodal biometric databases show that our feature transformation scheme is able to preserve the discrimination power of the original features more promisingly than state of the art transformation schemes we propose a feature transformation method to learn a histogram feature representation from the unordered features for multi biometric ordered feature fused template protection we devise a discriminative measure to guide the learning of histogram bins for deriving a discriminative histogram representation the proposed method is able to preserve the discrimination power of the unordered features very promisingly experiments on seven unimodal and three bimodal biometric datasets reveal that the proposed method achieves a better overall performance than the state of the arts

the value of markov chain games with lack of information on one side we consider a two player zero sum game given by a markov chain over a finite set of states and a family of matrix games indexed by states the sequence of states follows the markov chain at the beginning of each stage only player 1 is informed of the current state then the corresponding matrix game is played and the actions chosen are observed by both players before proceeding to the next stage we call such a game a markov chain game with lack of information on one side this model generalizes the model of aumann and maschler of zero sum repeated games with lack of information on one side which corresponds to the case where the transition matrix of the markov chain is the identity matrix we generalize the proof of aumann and maschler and from the definition and the study of appropriate nonrevealing auxiliary games with infinitely many stages show the existence of the uniform value an important difference with aumann and maschler s model is that here the notions for player 1 of using the information and revealing a relevant information are distinct

extension of isometries between unit spheres of finite dimensional polyhedral banach spaces abstract we prove that an onto isometry between unit spheres of finite dimensional polyhedral banach spaces extends to a linear isometry of the corresponding spaces

belief free communication equilibria in repeated games this paper considers a general model of repeated games with incomplete information and imperfect monitoring we study belief free communication equilibria bfce defined as follows players communicate with a mediator who receives types and signals and recommends actions a bfce is a communication device such that all players have an incentive to play faithfully irrespectively of their belief about the state we characterize bfce payoffs for any repeated game with incomplete information in terms of one shot payoff functions information and signaling structure

tingley s problem for spaces of trace class operators abstract we prove that every surjective isometry between the unit spheres of two trace class spaces admits a unique extension to a surjective complex linear or conjugate linear isometry between the spaces this provides a positive solution to tingley s problem in a new class of operator algebras

on the limits of communication in multidimensional cheap talk a comment we analyze a cheap talk game a la crawford and sobel in a multidimensional state and policy space a feature of the multidimensional state space is that communication on one dimension often reveals information on others we show how this feature imposes bounds on communication

inference based similarity search in randomized montgomery domains for privacy preserving biometric identification similarity search is essential to many important applications and often involves searching at scale on high dimensional data based on their similarity to a query in biometric applications recent vulnerability studies have shown that adversarial machine learning can compromise biometric recognition systems by exploiting the biometric similarity information existing methods for biometric privacy protection are in general based on pairwise matching of secured biometric templates and have inherent limitations in search efficiency and scalability in this paper we propose an inference based framework for privacy preserving similarity search in hamming space our approach builds on an obfuscated distance measure that can conceal hamming distance in a dynamic interval such a mechanism enables us to systematically design statistically reliable methods for retrieving most likely candidates without knowing the exact distance values we further propose to apply montgomery multiplication for generating search indexes that can withstand adversarial similarity analysis and show that information leakage in randomized montgomery domains can be made negligibly small our experiments on public biometric datasets demonstrate that the inference based approach can achieve a search accuracy close to the best performance possible with secure computation methods but the associated cost is reduced by orders of magnitude compared to cryptographic primitives

a note on non support points negligible sets gâteaux differentiability and lipschitz embeddings abstract this paper first presents a characterization of three classes of negligible closed convex sets i e gauss null sets aronszajn null sets and cube null sets in terms of non support points then gives a generalization of g teaux differentiability theorems of lipschitz mapping from open sets to those closed convex sets admitting non support points and as their application finally shows that a closed convex set in a separable banach space x can be lipschitz embedded into a banach space y with the radon nikodym property if and only if the closure of its linear span is linearly isomorphic to a closed subspace of y

the value of markov chain games with incomplete information on both sides we consider zero sum repeated games with incomplete information on both sides where the states privately observed by each player follow independent markov chains it generalizes the model introduced by aumann and maschler in the sixties and solved by mertens and zamir in the seventies where the private states of the players were fixed it also includes the model introduced in renault 19 renault j 2006 the value of markov chain games with lack of information on one side math oper res 31 3 490 512 of markov chain repeated games with lack of information on one side where only one player privately observes the sequence of states we prove here that the limit value exists and we obtain a characterization via the mertens zamir system where the nonrevealing value function plugged in the system is now defined as the limit value of an auxiliary nonrevealing dynamic game this nonrevealing game is defined by restricting the players not to reveal any information on the limit behavior of their

sharp corner points and isometric extension problem in banach spaces abstract in this article we begin using some geometric methods to study the isometric extension problem in general real banach spaces for any banach space y we define a collection of sharp corner points of the unit ball b 1 y which is empty if y is strictly convex and dim y 2 then we prove that any surjective isometry between two unit spheres of banach spaces x and y has a linear isometric extension on the whole space if y is a g teaux differentiability space in particular separable spaces or reflexive spaces and the intersection of sharp corner points and weak exposed points of b y is weak dense in the latter moreover we study the sharp corner points in many classical banach spaces and solve isometric extension problem affirmatively in the case that y is l 1 c 0 c l or some c

selecting cheap talk equilibria there are typically multiple equilibrium outcomes in the crawford sobel cs model of strategic information transmission this paper identifies a simple condition on equilibrium payoffs called nits no incentive to separate that selects among cs equilibria under a commonly used regularity condition only the equilibrium with the maximal number of induced actions satisfies nits we discuss various justifications for nits including perturbed cheap talk games with nonstrategic players or costly lying we also apply nits to other models of cheap talk illustrating its potential beyond the cs framework

fair distribution protocols or how the players replace fortune there are n 2 players p1 p2 pn each of them having a finite alphabet a1 an and there is a probability distribution p on a a1 an the players want to choose a a according to p in such a way that pk knows only the kth component ak of a this can be done with the help of an impartial person or fortune who chooses a a according to p and informs pk on ak only but what happens if no such person is available can the players find a procedure that replaces fortune it is proved here that the answer is yes when n 4 as an application it is shown that a correlated equilibrium of a noncooperative n person game n 4 coincides with a nash equilibrium of an extended game involving in addition plain conversations only

a note on the mazur ulam property of almost cl spaces abstract we introduce the t property and prove that every banach space with the t property has the mazur ulam property for short mup we obtain as its immediate applications that almost cl spaces admitting a smooth point in particular separable almost cl spaces and a two dimensional space whose unit sphere is a hexagon have the mup furthermore we discuss the stability of the spaces having the mup derived from the c 0 and l 1 sums and show that the space c k x of the vector valued continuous functions has the mup where x is a separable almost cl space and k is a compact metric space

nash codes for noisy channels this paper studies the stability of communication protocols that deal with transmission errors we consider a coordination game between an informed sender and an uninformed receiver who communicate over a noisy channel the sender s strategy called a code maps states of nature to signals the receiver s best response is to decode the received channel output as the state with highest expected receiver payoff given this decoding an equilibrium or nash code results if the sender encodes every state as prescribed we show two theorems that give sufficient conditions for nash codes first a receiver optimal code defines a nash code a second more surprising observation holds for communication over a binary channel which is used independently a number of times a basic model of information transmission under a minimal monotonicity requirement for breaking ties when decoding which holds generically every code is a nash code

two player repeated games with nonobservable actions and observable payoffs this paper studies two person repeated games in which after each stage a player is informed about the payoff he received at the previous stage the information can in some cases include more than that four kinds of nash equilibrium concepts are defined by the limit of the means a characterization of the equilibrium payoffs sets and several properties of these sets are given as a specific example the standard information case that of the folk theorem is provided

from fuzzy regression to gradual regression interval based analysis and extensions abstract this paper proposes an analysis of parametric interval based regression methodologies according to ontic and epistemic visions of intervals when assuming an epistemic point of view a new interpretation of fuzzy regression through the notion of gradual intervals is developed which leads to gradual regression gradual regression is viewed as an extension of the imprecise interval based regression which is obtained by integrating an uncertain dimension gradual intervals can yield improved specificity compared to conventional intervals and jointly consider the concepts of imprecision and uncertainty through a single and coherent formalism the formulation of the gradual regression problem its resolution and the propagation of the information through the obtained regressive models are carried out via gradual interval arithmetic the proposed method allows not only the extension of the interval vision to the gradual case but also interesting interpretations according to non additive confidence measure theories possibility and belief functions

continuous affine support mappings for convex operators abstract we investigate the problem of existence of continuous affine resp linear support mappings for convex resp sublinear partially defined operators we prove that a weakly borel measurable convex operator defined on a closed convex subset of a locally convex frechet space with values in an ordered locally convex vector space with the least upper bound property and an order unit inducing the topology in fact has continuous affine support mappings we give an example indicating that the order unit being present is essential a step towards our result is provided by a variant of the sandwich theorem obtained for the case of weakly borel measurable convex and concave operators finally we obtain necessary and sufficient conditions for the existence of a continuous affine support mapping h for a convex operator such that h x 0 x 0 holds for a fixed point x 0 in terms of the upper directional derivate x 0 for at x 0

orientation selection using modified fcm for competitive code based palmprint recognition coding based methods are among the most promising palmprint recognition methods because of their small feature size fast matching speed and high verification accuracy the competitive coding scheme one representative coding based method first convolves the palmprint image with a bank of gabor filters with different orientations and then encodes the dominant orientation into its bitwise representation despite the effectiveness of competitive coding few investigations have been given to study the influence of the number of gabor filters and the orientation of each gabor filter in this paper based on the statistical orientation distribution and the orientation separation characteristics we propose a modified fuzzy c means cluster algorithm to determine the orientation of each gabor filter since the statistical orientation distribution is based on a set of real palmprint images the proposed method is more suitable for palmprint recognition experimental results indicate that the proposed method achieves higher verification accuracy while compared with that of the original competitive coding scheme and several state of the art methods such as ordinal measure and rloc considering both the computational complexity and the verification accuracy competitive code with six orientations would be the optimal choice for palmprint recognition

tingley s problem through the facial structure of operator algebras abstract tingley s problem asks whether every surjective isometry between the unit spheres of two banach spaces admits an extension to a real linear surjective isometry between the whole spaces in this paper we give an affirmative answer to tingley s problem when both spaces are preduals of von neumann algebras the spaces of self adjoint operators in von neumann algebras or the spaces of self adjoint normal functionals on von neumann algebras we also show that every surjective isometry between the unit spheres of unital c algebras restricts to a bijection between their unitary groups in addition we show that every surjective isometry between the normal state spaces or the normal quasi state spaces of two von neumann algebras extends to a linear surjective isometry

belief free equilibria in games with incomplete information we define belief free equilibria in two player games with incomplete information as sequential equilibria for which players continuation strategies are best replies after every history independently of their beliefs about the state of nature we characterize a set of payoffs that includes all belief free equilibrium payoffs conversely any payoff in the interior of this set is a belief free equilibrium payoff the characterization is applied to the analysis of reputations

on a generalized mazur ulam question extension of isometries between unit spheres of banach spaces abstract we call a banach space x admitting the mazur ulam property mup provided that for any banach space y if f is an onto isometry between the two unit spheres of x and y then it is the restriction of a linear isometry between the two spaces a generalized mazur ulam question is whether every banach space admits the mup in this paper we show first that the question has an affirmative answer for a general class of banach spaces namely somewhere flat spaces as their immediate consequences we obtain on the one hand that the question has an approximately positive answer given e 0 every banach space x admits a 1 e equivalent norm such that x has the mup on the other hand polyhedral spaces cl spaces admitting a smooth point in particular separable cl spaces have the mup

the mazur ulam property for two dimensional somewhere flat spaces abstract in this paper we show that if x is a two dimensional real normed space such that its unit sphere contains a line segment with the distance between its endpoints being greater than 1 then x has the mazur ulam property that is every isometry from the unit sphere of x onto the unit sphere of any normed space y can be extended to a linear isometry from x onto y

multi agent inference in social networks a finite population learning approach when people in a society want to make inference about some parameter each person may want to use data collected by other people information data exchange in social networks is usually costly so to make reliable statistical decisions people need to weigh the benefits and costs of information acquisition conflicts of interests and coordination problems will arise in the process classical statistics does not consider people s incentives and interactions in the data collection process to address this imperfection this work explores multi agent bayesian inference problems with a game theoretic social network model motivated by our interest in aggregate inference at the societal level we propose a new concept finite population learning to address whether with high probability a large fraction of people in a given finite population network can make good inference serving as a foundation this concept enables us to study the long run trend of aggregate inference quality as population grows supp

spherical isometries of finite dimensional c algebras abstract in this paper it is shown that every surjective isometry between the unit spheres of two finite dimensional c algebras extends to a real linear jordan isomorphism followed by multiplication operator by a fixed unitary element this gives an affirmative answer to tingley s problem between two finite dimensional c algebras moreover we show that if two finite dimensional c algebras have isometric unit spheres then they are isomorphic

player type distributions as state variables and information revelation in zero sum repeated games with discounting this paper examines the role of the player type distributions in repeated zero sum games of incomplete information with discounting of payoffs in particular the strategic sufficiency of the posterior distributions for histories and the limiting properties of the posterior sequence are discussed it is shown that differentiability of the value function is sufficient to allow the posteriors to serve as state variables for histories the limiting properties of the posterior distributions are considered and a characterization given of the set of possible limit points of the posterior distribution this characterization is given in terms of the value of information in the one stage game

a novel encoding scheme for effective biometric discretization linearly separable subcode separability in a code is crucial in guaranteeing a decent hamming distance separation among the codewords in multibit biometric discretization where a code is used for quantization intervals labeling separability is necessary for preserving distance dissimilarity when feature components are mapped from a discrete space to a hamming space in this paper we examine separability of binary reflected gray code brgc encoding and reveal its inadequacy in tackling interclass variation during the discrete to binary mapping leading to a tradeoff between classification performance and entropy of binary output to overcome this drawback we put forward two encoding schemes exhibiting full ideal and near ideal separability capabilities known as linearly separable subcode lssc and partially linearly separable subcode plssc respectively these encoding schemes convert the conventional entropy performance tradeoff into an entropy redundancy tradeoff in the increase of code length extensive experimental results vindicate the superiority of our schemes over the existing encoding schemes in discretization performance this opens up possibilities of achieving much greater classification performance with high output entropy

certifiable pre play communication full disclosure this article asks when communication with certifiable information leads to complete information revelation we consider bayesian games augmented by a pre play communication phase in which announcements are made publicly we first characterize the augmented games in which there exists a fully revealing sequential equilibrium with extremal beliefs i e any deviation is attributed to a single type of the deviator next we define a class of games for which existence of a fully revealing equilibrium is equivalent to a richness property of the evidence structure this characterization enables us to provide different sets of sufficient conditions for full information disclosure that encompass and extend all known results in the literature and are easily applicable we use these conditions to obtain new insights in games with strategic complementarities voting with deliberation and persuasion games with multidimensional types

learning sets in state dependent signalling game forms a characterization we consider repeated game forms with incomplete information and state dependent signalling structure we study the information a player can learn about the state of nature through a communication procedure in a way robust to unilateral deviations more precisely we say that playeri can distinguish state from state if there exists a strategy profile such that if is the true state and at most one player deviates from the profile then playeri will know after a finite number of stages that is not the true state the learning set of playeri at is the set of states that playeri cannot distinguish from it corresponds to the information playeri can learn in a way immune against unilateral deviations if the state is and players communicate through the game form for a finite number of stages this notion was introduced in a joint paper with t tomala renault and tomala 2000 we provide here a general characterization of the learning sets

randomized quantization and source coding with constrained output distribution this paper studies fixed rate randomized vector quantization under the constraint that the quantizer s output has a given fixed probability distribution a general representation of randomized quantizers that includes the common models in the literature is introduced via appropriate mixtures of joint probability measures on the product of the source and reproduction alphabets using this representation and results from optimal transport theory the existence of an optimal minimum distortion randomized quantizer having a given output distribution is shown under various conditions for sources with densities and the mean square distortion measure it is shown that this optimum can be attained by randomizing quantizers having convex codecells for stationary and memoryless source and output distributions a rate distortion theorem is proved providing a single letter expression for the optimum distortion in the limit of large blocklengths

some asymptotic results in discounted repeated games of one sided incomplete information the paper analyzes the nash equilibria of two person discounted repeated games with one sided incomplete information and known own payoffs if the informed player is arbitrarily patient relative to the uninformed player then the characterization for the informed player s payoffs is essentially the same as that in the undiscounted case this implies that even small amounts of incomplete information can lead to a discontinuous change in the equilibrium payoff set for the case of equal discount factors however and under an assumption that strictly individually rational payoffs exist a result akin to the folk theorem holds when a complete information game is perturbed by a small amount of incomplete information

modeling the shape of the scene a holistic representation of the spatial envelope in this paper we propose a computational model of the recognition of real world scenes that bypasses the segmentation and the processing of individual objects or regions the procedure is based on a very low dimensional representation of the scene that we term the spatial envelope we propose a set of perceptual dimensions naturalness openness roughness expansion ruggedness that represent the dominant spatial structure of a scene then we show that these dimensions may be reliably estimated using spectral and coarsely localized information the model generates a multidimensional space in which scenes sharing membership in semantic categories e g streets highways coasts are projected closed together the performance of the spatial envelope model shows that specific information about object shape or identity is not a requirement for scene categorization and that modeling a holistic representation of the scene informs about its probable semantic category

a reflection on tingley s problem and some applications abstract in this paper we show how some metric properties of the unit sphere of a normed space can help to approach a solution to tingley s problem in our main result we show that if an onto isometry between the spheres of strictly convex spaces is the identity when restricted to some relative open subset then it is the identity this implies that an onto isometry between the unit spheres of strictly convex finite dimensional spaces is linear if and only if it is linear on a relative open set we prove the same for arbitrary two dimensional spaces and obtain that every two dimensional non strictly convex normed space has the mazur ulam property we also include some other less general yet interesting results along with a generalisation of curvature to normed spaces

games with incomplete information played by bayesian players i iii this article originally appeared in management science november 1967 volume 14 number 3 pp 159 182 published by the institute of management sciences the paper develops a new theory for the analysis of games with incomplete information where the players are uncertain about some important parameters of the game situation such as the payoff functions the strategies available to various players the information other players have about the game etc however each player has a subjective probability distribution over the alternative possibilities in most of the paper it is assumed that these probability distributions entertained by the different players are mutually consistent in the sense that they can be regarded as conditional probability distributions derived from a certain basic probability distribution over the parameters unknown to the various players but later the theory is extended also to cases where the different players subjective probability distributions fail to satisfy this consistency assumption in cases where the consistency assumption holds the original game can be replaced by a game where nature first conducts a lottery in accordance with the basic probability distribution and the outcome of this lottery will decide which particular subgame will be played i e what the actual values of the relevant parameters will be in the game yet each player will receive only partial information about the outcome of the lottery and about the values of these parameters however every player will know the basic probability distribution governing the lottery thus technically the resulting game will be a game with complete information it is called the bayes equivalent of the original game part i of the paper describes the basic model and discusses various intuitive interpretations for the latter part ii shows that the nash equilibrium points of the bayes equivalent game yield bayesian equilibrium points for the original game finally part iii considers the main properties of the basic probability distribution

product quantization for nearest neighbor search this paper introduces a product quantization based approach for approximate nearest neighbor search the idea is to decompose the space into a cartesian product of low dimensional subspaces and to quantize each subspace separately a vector is represented by a short code composed of its subspace quantization indices the euclidean distance between two vectors can be efficiently estimated from their codes an asymmetric version increases precision as it computes the approximate distance between a vector and a code experimental results show that our approach searches for nearest neighbors efficiently in particular in combination with an inverted file system results for sift and gist image descriptors show excellent search accuracy outperforming three state of the art approaches the scalability of our approach is validated on a data set of two billion vectors

on the extension of isometries between the unit spheres of von neumann algebras abstract we prove that every surjective isometry between the unit spheres of two von neumann algebras admits a unique extension to a surjective real linear isometry between these two algebras

tingley s problem through the facial structure of an atomic jbw triple abstract we prove that every surjective isometry between the unit spheres of two atomic jbw triples e and b admits a unit extension to a surjective real linear isometry from e into b this result constitutes a new positive answer to tingley s problem in the jordan setting

interval arithmetic based simple linear regression between interval data discussion and sensitivity analysis on the choice of the metric the prediction of a response random interval valued set from an explanatory one has been examined in previous developments these developments have considered an interval arithmetic based linear model between the random interval valued sets and a least squares regression analysis the least squares approach involves a generalized l 2 metric between interval data this metric weights squared distances between data location mid points centers and squared distances between data imprecision spread radius as a consequence estimators of the parameters in the linear model depend on the choice of the weights in the metric to investigate about a suitable choice of weighting in the generalized mid spread metric a theoretical conclusion is first obtained finally the impact of varying the weights is discussed by considering a monte carlo simulation study

communication equilibria in repeated games with incomplete information correlated equilibria in the sense of aumann i e normal form correlated equilibria are studied in two person infinitely repeated games with lack of information on one side extensions of the solution concept are introduced several of which are shown to be payoff equivalent in the model under consideration a normal form correlated equilibrium is a nash equilibrium of the game where each player gets a private output from a correlation device before the beginning of the original game an r device r 0 1 is a communication device receiving an input from each player before every stage t 1 r and selecting a pair of outputs one for each player at every stage t 1 2 according to a memory dependent transition probability an r communication equilibrium is a nash equilibrium of the game extended by means of an r device let c resp dr r 0 1 be the set of normal form correlated resp r communication equilibrium payoffs d0 is the set of extensive form correlated equilibrium payoffs achieved by means of an autonomous device acting only by sending a stream of outputs to each player and d is the set of all communication equilibrium payoffs corresponding to communication devices which can receive inputs at every stage even arbitrarily large the paper characterizes the different sets and investigate whether they coincide

guaranteed performance regions in markovian systems with competing decision makers a decision maker is facing a dynamic system which is being controlled by himself herself as well as by other decision makers he she considers a vector of performance measures acceptable performance is defined through a set in the space of performance vectors whether this decision maker can guarantee a time averaged performance vector which approaches this desired set is considered for the worst case scenario in which other decision makers may for selfish reasons try to exclude his her vector from the desired set for a controlled markov model of the system a sufficient condition for approachability is given and appropriate control strategies are constructed under certain recurrence conditions a complete characterization of approachability is then provided for convex sets the mathematical formulation leads to a theory of approachability for stochastic games with vector payoffs a simple queuing example illustrates this approach

approximation of functional relationships to fuzzy observations abstract for approximating functional relationships to fuzzy observations there exist several approaches joining some communities the functional relationship is still kept a fuzzy function even if the observations are crisp the case of crisp observations often requires specific considerations in this paper an approximation method using hausdorff like distances is proposed naturally containing the crisp observation case and leading to a crisp function for crisp observations additional the proposed method leads to well known approximation principles from classical theory and can be realized by standard computer software a simple example completes the considerations

generic gâteaux differentiability of convex functions on small sets the theory of generic differentiability of convex functions on banach spaces is by now a well explored part of infinite dimensional geometry all the attempts to solve this kind of problem have in common as a working hypothesis one special feature of the finite dimensional case namely convex functions are always considered to be defined on convex sets with nonempty interior but typically a convex set in a banach space does not have interior points even when it is not contained in a closed hyperplane so this raises the problem of expounding a theory of differentiability of convex functions defined on small sets i e sets without interior points in our paper n2 we have made an attempt to solve this problem discussing questions of generic frechet differentiability of convex functions on small sets in the present paper we deal with problems of generic gateauxdifferentiability in this context

a set arithmetic based linear regression model for modelling interval valued responses through real valued variables a new linear regression model for an interval valued response and a real valued explanatory variable is presented the approach is based on the interval arithmetic comparisons with previous methods are discussed the new linear model is theoretically analyzed and the regression parameters are estimated some properties of the regression estimators are investigated finally the performance of the procedure is illustrated using both a real life application and simulation studies

non zero sum two person repeated games with incomplete information characterization of all equilibria of nonzero sum two person repeated games with incomplete information in the standard one sided information case informally each such equilibrium is described by a sequence of communications between the players consisting of information transmission and coordination leading to some individually rational agreement formally the concept of a bi martingale is introduced

ldahash improved matching with smaller descriptors sift like local feature descriptors are ubiquitously employed in computer vision applications such as content based retrieval video analysis copy detection object recognition photo tourism and 3d reconstruction feature descriptors can be designed to be invariant to certain classes of photometric and geometric transformations in particular affine and intensity scale transformations however real transformations that an image can undergo can only be approximately modeled in this way and thus most descriptors are only approximately invariant in practice second descriptors are usually high dimensional e g sift is represented as a 128 dimensional vector in large scale retrieval and matching problems this can pose challenges in storing and retrieving descriptor data we map the descriptor vectors into the hamming space in which the hamming metric is used to compare the resulting representations this way we reduce the size of the descriptors by representing them as short binary strings and learn descriptor invariance from examples we show extensive experimental validation demonstrating the advantage of the proposed approach

on two player repeated games with lack of information on one side and state independent signalling we consider two person undiscounted repeated games with lack of information on one side and state independent signalling and prove the existence of a joint plan uniform equilibrium

on optimal rules of persuasion a speaker wishes to persuade a listener to accept a certain request the conditions under which the request is justified from the listener s point of view depend on the values of two aspects the values of the aspects are known only to the speaker and the listener can check the value of at most one a mechanism specifies a set of messages that the speaker can send and a rule that determines the listener s response namely which aspect he checks and whether he accepts or rejects the speaker s request we study mechanisms that maximize the probability that the listener accepts the request when it is justified and rejects the request when it is unjustified given that the speaker maximizes the probability that his request is accepted we show that a simple optimal mechanism exists and can be found by solving a linear programming problem in which the set of constraints is derived from what we call the l principle

the mazur ulam property in l sum and c0 sum of strictly convex banach spaces abstract in this paper we deal with those banach spaces z which satisfy the mazur ulam property namely that every surjective isometry from the unit sphere of z to the unit sphere of any banach space y admits a unique extension to a surjective real linear isometry from z to y we prove that for every countable set with 2 the banach space c 0 x satisfies the mazur ulam property whenever the banach space x is strictly convex with dim x r 2 for every as a consequence every weakly countably determined banach space can be equivalently renormed so that it satisfies the mazur ulam property

computational complexity and communication coordination in two player games the main contribution of this paper is the development and application of cryptographic techniques to the design of strategic communication mechanisms one of the main assumptions in cryptography is the limitation of the computational power available to agents we introduce the concept of limited computational complexity and by borrowing results from cryptography we construct a communication protocol to establish that every correlated equilibrium of a two person game with rational payoffs can be achieved by means of computationally restricted unmediated communication this result provides an example in game theory where limitations of computational abilities of players are helpful in solving implementation problems more specifically it is possible to construct mechanisms with the property that profitable deviations are too complicated to compute

reputation and commitment in two person repeated games without discounting two person repeated games with no discounting are considered where there is uncertainty about the type of the players if there is a possibility that a player is an automaton committed to a particular pure or mixed stage game action then this provides a lower bound on the nash equilibrium payoffs to a normal type of this player the lower bound is the best available and is robust to the existence of other types the results are extended to the case of two sided uncertainty this work extends schmidt 1993 who analysed the restricted class of conflicting interest games