a simple resampling method by perturbing the minimand suppose that under a semiparametric setting an estimator of a vector of parameters of interest is obtained by optimising an objective function which has a u process structure the covariance matrix of the estimator is generally a function of the underlying density function which may be difficult to estimate well by conventional methods in this paper we present a simple resampling method by perturbing the objective function repeatedly inferences of the parameters can then be made based on a large collection of the resulting optimisers we illustrate our proposal by three examples with a heteroscedastic regression model

order preservation in limit algebras abstract the matrix units of a digraph algebra a induce a relation known as the diagonal order on the projections in a masa in the algebra normalizing partial isometries in a act on these projections by conjugation they are said to be order preserving when they respect the diagonal order order preserving embeddings in turn are those embeddings which carry order preserving normalizers to order preserving normalizers this papers studies operator algebras which are direct limits of finite dimensional algebras with order preserving embeddings we give a complete classification of direct limits of full triangular matrix algebras with order preserving embeddings we also investigate the problem of characterizing algebras with order preserving embeddings

abstract minimality and circumscription abstract in this paper we present an alternative approach to the generalization of circumscription traditionally the generalization of circumscription involves the change of ordering among models while in the present study we only try to generalize the minimality criteria of models we define the notion of abstractly minimal or p z minimal models by isomorphism under this generalization we come up with the fact that some theories which are unsatisfiable in the original circumscription will be satisfiable now moreover we prove that this generalization is completely coincident with the original circumscription in the case of well founded theories

on estimation of partially linear transformation models we study a general class of partially linear transformation models which extend linear transformation models by incorporating nonlinear covariate effects in survival data analysis a new martingale based estimating equation approach consisting of both global and kernel weighted local estimation equations is developed for estimating the parametric and nonparametric covariate effects in a unified manner we show that with a proper choice of the kernel bandwidth parameter one can obtain the consistent and asymptotically normal parameter estimates for the linear effects asymptotic properties of the estimated nonlinear effects are established as well we further suggest a simple resampling method to estimate the asymptotic variance of the linear estimates and show its effectiveness to facilitate the implementation of the new procedure an iterative algorithm is developed numerical examples are given to illustrate the finite sample performance of the procedure supplementary materials are available online

a resampling method based on pivotal estimating functions summary suppose that under a semiparametric model setting one is interested in drawing inferences about a finite dimensi onal parameter vector based on an estimating function generally a consistent point estimator j for 0 the true value for j can be easily obtained by finding a root of the corresponding estimating equation to estimate the variance of ft however may involve complicated and subjective nonparametric functional estimates in this paper a general and simple resampling method for inferences about js0 based on pivotal estimating functions is proposed the new procedure is illustrated with the quantile and rank regression models for both cases our proposal can be easily and efficiently implemented with existing statistical software

the suprem architecture a new intelligent paradigm abstract we investigate the model theory of the notion of circumscription and find completeness theorems that provide a partial converse to a result of mccarthy we show that the circumscriptive theorems are precisely the truths of the minimal models in the case of various classes of theories and for various versions of circumscription we also present an example of commonsense reasoning in which first order circumscription does not achieve the intuitive and desired minimization

on conjugacy of masas and the outer automorphism group of the cuntz algebra we investigate the structure of the outer automorphism group of the cuntz algebra and closely related with this problem of conjugacy of masaa in on in particular we exhibit an uncountable family of masas conjugate to the standard masa dn via bogolubov automorphisms that are not inner conjugate to dn

censored regression quantiles abstract the object of this paper is to demonstrate how the lad estimation method for the censored regression model can be extended to more general quantiles in this paper the form of the conditional quantiles for the censored regression models is heuristically derived and discussed the resulting estimators of the regression coefficients which include the censored lad estimator as a special case are shown to be consistent and asymptotically normally distributed under appropriately translated versions of the corresponding assumptions for the former approach consistent estimation of the asymptotic covariance matrix when the error terms are i i d is also treated the paper discussed how several quantile estimators might be combined to improve efficiency when the error terms are identically distributed and how tests of homoskedasticity and symmetry of the error distribution can be constructed using particular differences of the estimated coefficients

the importance of open and recursive circumscription research note abstract circumscription is known to result in an inconsistency when applied to certain consistent theories to counter this problem closed nonrecursive circumscription a restricted form of circumscription that has been proved not to affect the consistency of the theory over which circumscription is applied has been proposed we show that closed nonrecursive circumscription involves an excessive weakening of standard circumscription by establishing that closed nonrecursive circumscription is incomplete for some crucial theories over which standard circumscription is consistent and complete first we prove that closed circumscription cannot yield the desired uniqueness formula for the simplest of existential theories second we prove that nonrecursive circumscription fails to be as strong as predicate completion for horn clause theories third we prove that the natural way to strengthen circumscription that is adding more variable predicates may weaken nonrecursive circumscription

approximately finitely acting operator algebras let e be an operator algebra on a hilbert space with finite dimensional c algebra c e a classification is given of the locally finite algebras a0 formula ak k and the operator algebras a formula ak k obtained as limits of direct sums of matrix algebras over e with respect to star extendible homomorphisms the invariants in the algebraic case consist of an additive semigroup with scale which is a right module for the semiring ve homu e e of unitary equivalence classes of star extendible homomorphisms this semigroup is referred to as the dimension module invariant in the operator algebra case the invariants consist of a metrized additive semigroup with scale and a contractive right module ve action subcategories of algebras determined by restricted classes of embeddings such as 1 decomposable embeddings between digraph algebras are also classified in terms of simplified dimension modules

on the satisfiability of circumscription abstract etherington mercer and reiter showed on the basis of ideas of bossu and siegel that circumscription cannot lead to inconsistency for universal formulas we extend this result in three directions to formulas of a more general syntactic form to circumscription with some predicate symbols allowed to vary and to prioritized circumscription

quantile correlations and quantile autoregressive modeling in this article we propose two important measures quantile correlation qcor and quantile partial correlation qpcor we then apply them to quantile autoregressive qar models and introduce two valuable quantities the quantile autocorrelation function qacf and the quantile partial autocorrelation function qpacf this allows us to extend the box jenkins three stage procedure model identification model parameter estimation and model diagnostic checking from classical autoregressive models to quantile autoregressive models specifically the qpacf of an observed time series can be employed to identify the autoregressive order while the qacf of residuals obtained from the fitted model can be used to assess the model adequacy we not only demonstrate the asymptotic properties of qcor and qpcor but also show the large sample results of qacf qpacf and the quantile version of the box pierce test moreover we obtain the bootstrap approximations to the distributions of parameter estimators and p

limit theorems for u processes a u process is a collection of u statistics concretely a u process over a family h of kernels h of m variables based on a probability measure p on s s is the collection u n m h p h in mathcal h of u statistics this chapter is devoted to the asymptotic theory of u processes we are interested in finding conditions on h and p ensuring that the law of large numbers or the central limit theorem or the law of the iterated logarithm hold for u n m h p uniformly in h h the theory of empirical processes deals with the same questions for the case m 1 and u process theory is patterned after it this is a relatively new subject at least in the generality presented here h being an arbitrary collection of kernels which are defined on a general measurable space there is therefore a need to indicate its usefulness to this effect a section on applications is added at the end of the chapter section 5 5 there we illustrate the use of each of the main theorems in this chapter by deriving properties of certain multidimensional generalizations of the median and in general of m estimators and by studying estimators of the cumulative hazard and distribution functions of a random variable based on truncated data

least absolute deviations estimation for the censored regression model this paper proposes an alternative to maximum likelihood estimation of the parameters of the censored regression or censored tobit model the proposed estimator is a generalization of least absolute deviations estimation for the standard linear model and unlike estimation methods based on the assumption of normally distributed error terms the estimator is consistent and asymptotically normal for a wide class of error distributions and is also robust to heteroscedasticity the paper gives the regularity conditions and proofs of these large sample results and proposes classes of consistent estimators of the asymptotic covariance matrix for both homoscedastic and heteroscedastic disturbances

homology for operator algebras ii stable homology for non self adjoint algebras new homology groups are defined for a non self adjoint operator algebra with a distinguished masa which is based upon cycles and boundaries associated with complexes of partial isometries in the stable algebra under natural hypotheses the zeroth order group coincides with thek0group of the generatedc algebra several identifications and applications are given and in particular it is shown how stable homology is significant for the classification of regular subalgebras and regular limit algebras

u processes rates of convergence on introduit un nouveau processus stochastique une collection de statistiques u indicees par une famille de noyaux symetriques on obtient des conditions pour la convergence presque sure uniforme d une suite de tels processus

relative positions of matroid algebras abstract a classification is given for regular positions d d d of jones index 4 where equation omitted is an even matroid algebra and where the individual summands have index 2 a similar classification is obtained for positions of direct sums of 2 symmetric algebras and in the odd case for the positions of sums of 2 symmetric c algebras in matroid c algebras the approach relies on an analysis of intermediate non self adjoint operator algebras and the classifications are given in terms of k0 invariants partial isometry homology and scales in the composite invariant k0 h1

homology for operator algebras abstract a 4 cycle algebra is a finite dimensional digraph algebra csl algebra whose reduced digraph is a 4 cycle a rigid embedding between such algebras is a direct sum of certain nondegenerate multiplicity one star extendible embeddings a complete classification is obtained for the regular isomorphism classes of direct systems a of 4 cycle algebras with rigid embeddings the critical invariant is a binary relation in k 0 a h 1 a generalising the scale of the k 0 group called the joint scale the joint scale encapsulates other invariants and compatibility conditions of regular isomorphism these include the scale of h 1 a the scale of h 0 a h 1 a sign compatibility congruence compatibility and h 0 h 1 coupling classes these invariants are also important for lifting k 0 h 1 isomorphisms to algebra isomorphisms we resolve this lifting problem for various classes of 4 cycle algebra direct systems

the restricted weyl group of the cuntz algebra and shift endomorphisms it is shown that modulo the automorphisms which fix the canonical diagonal masa point wise the group of those automorphisms of on which globally preserve both the diagonal and the core uhf subalgebra is isomorphic via restriction with the group of those homeomorphisms of the full one sided n shift space which eventually commute along with their inverses with the shift transformation the image of this group in the outer automorphism group of on can be embedded into the quotient of the automorphism group of the full two sided n shift by its center generated by the shift if n is prime then this embedding is an isomorphism msc 2010 46l40 37b10

applications of circumscription to formalizing common sense knowledge we present a new and more symmetric version of the circumscription method of nonmonotonic reasoning first described in mccarthy 1980 and some applications to formalizing common sense knowledge the applications in this paper are mostly based on minimizing the abnormality of different aspects of various entities included are nonmonotonic treatments of is a hierarchies the unique names hypothesis and the frame problem the new circumscription may be called formula circumscription to distinguish it from the previously defined domain circumscription and predicate circumscription a still more general formalism called prioritized circumscription is briefly explored

an interior point algorithm for nonlinear quantile regression abstract a new algorithm for computing quantile regression estimates for problems in which the response function is nonlinear in parameters is described the nonlinear l 1 estimation problem is a special median case the algorithm is closely related to recent developments on interior point methods for solving linear programs performance of the algorithm on a variety of test problems including the censored linear quantile regression problem of powell 1986 is reported

the uniqueness of af diagonals in regular limit algebras necessary and sufficient conditions are obtained for the uniqueness of standard regular af maximal abelian self adjoint algebras in regular limit algebras up to approximate inner unitary equivalence

saturation nonmonotonic reasoning and the closed world assumption abstract to deal with the problem of implicit negative information in databases it is necessary to use a nonmonotonic form of reasoning the form of reasoning described in this paper uses an ordering relation on interpretations of the type i is inferior to j if every elementary fact true in i is true in j in simple cases this rule may be defined by a set p of formulas implies a formula q if every minimal model of p satisfies q in more general cases this definition leads to paradox if p is consistent and has no minimal model p must not imply q and its negation we have 1 1 carefully formulated the definition of a special type of implication called sub implication to avoid this type of paradox 2 2 proved that if p is a set of clauses then p has a minimal model and more generally that every model of a set of clauses is minored by one of its minimal models 3 3 developed in this last case subject to certain conditions such as the use of a particular set of clauses called groundable clauses or g clauses a decidable algorithm to compute whether p implies q q being practically any formula

a theorem on the consistency of circumscription abstract this paper gives more general conditions under which mccarthy s circumscription is consistent allowing application of the method outside the domain of universal sentences it is shown that circumscription as presented here continues to correspond to the semantic model of minimization some applications are detailed