iterates of fuzzy circulant matrices abstract the iterates of circulant matrices under the max min product is investigated in this article it is shown that if the first row of a fuzzy circulant matrix is in decreasing order then the iterates of the circulant converge and if the first row is in increasing order then the iterates oscillate in both cases a complete description of the iterates is obtained as an application this yields an o n algorithm for computing the transitive closure of a certain type of fuzzy relation viz relations whose adjacency matrices are fuzzy circulants with decreasing first row

an upper bound on indices of finite fuzzy relations abstract let r be an arbitrary n n fuzzy matrix which represents a finite fuzzy relation d and k be the period and the index of r respectively in this paper we present some further results about d and k and point out that k n 1 n where n is the least common multiple of 1 2 n

time varying market efficiency of the gcc stock markets abstract this paper investigates the time varying levels of weak form market efficiency for the gcc stock markets over the period spanning from may 2005 to september 2013 we use two empirical approaches 1 the generalized autoregressive conditional heteroscedasticity in mean garch m model with state space time varying parameter kalman filter and 2 a rolling technique sample test of the fractional long memory parameter d as long memory estimation methods we use the detrended fluctuation analysis dfa technique the modified r s statistic the exact local whittle elw and the feasible exact local whittle felw methods moreover we use the bai and perron 1998 2003 multiple structural breaks technique to test and date the time varying behavior of stock market efficiency empirical results show that gcc markets have different degrees of time varying efficiency and also have experiencing periods of efficiency improvement results also show evidence of structural breaks in all gcc markets moreover we observe that the recent financial shocks such as arab spring and subprime crises have a significant impact on the time path evolution of market efficiency

on simultaneously nilpotent fuzzy matrices abstract nilpotent fuzzy matrices play a crucial role in the study of fuzzy matrices in this paper we shall extend the nilpotence to the notion of simultaneous nilpotence for a finite set of fuzzy matrices the notion of simultaneous nilpotence relates to the infinite products of a finite number of fuzzy matrices which converge to the zero matrix properties of the simultaneous nilpotence will be established in the study of consecutive powers of a fuzzy matrix a controllable fuzzy matrix can be characterized by an associated nilpotent fuzzy matrix in this paper we propose the notion of simultaneously controllable fuzzy matrices which can be thought of as a generalization of the notion of controllable fuzzy matrices similar to the nilpotent characterization for a controllable fuzzy matrix the simultaneously controllable fuzzy matrices can be characterized by a finite set of associated simultaneously nilpotent fuzzy matrices

on the power sequence of a fuzzy matrix with convex combination of max product and max min operations in the literature the powers of a fuzzy matrix with max min max product max archimedean t norm max t norm max arithmetic mean compositions have been studied it turns out that the limiting behavior of the powers of a fuzzy matrix depends on the composition involved in this paper we consider the powers of a fuzzy matrix with convex combination of max product and max min operations we show that the powers of a fuzzy matrix a with such operations are asymptotical p period if and only if the powers of an associated boolean matrix a are p periodic moreover necessary and sufficient conditions for such a fuzzy matrix to be nilpotent are proposed

a comparison of dea and sfa using micro and macro level perspectives efficiency of chinese local banks abstract this study investigates to which extent results produced by a single frontier model are reliable based on the application of data envelopment analysis and stochastic frontier approach to a sample of chinese local banks our findings show they produce a consistent trend on global efficiency scores over the years however rank correlations indicate they diverge with respect to individual performance diagnoses therefore these models provide steady information on the efficiency of the banking system as a whole but they become divergent at the individual level

milnor witt k groups of local rings abstract we introduce milnor witt k groups of local rings and show that the n th milnor witt k group of a local ring r which contains an infinite field of characteristic not 2 is the pull back of the n th power of the fundamental ideal in the witt ring of r and the n th milnor k group of r over the n th milnor k group of r modulo 2 this generalizes the work of morel hopkins on milnor witt k groups of a field

zero cycles and projective modules let a be a reduced affine k algebra of dimension n over an algebraically closed field k let fnko a denote the sub group of ko a generated by the images of all the residue fields of all smooth maximal ideals of height n for a module of finite projective dimension m let m denote the image of m in ko a for a projective a module p of rank n we define the nth chern class of p to be cn p e l i aip where p is the dual of p suppose fnko a has no n 1 torsion then our main result th 3 8 is that p has a free direct summand of rank one if and only if cn p 0 when the characteristic of k is zero or a is normal and n 3 it is known that fnko a is torsion free le sr hence our theorem is applicable in these cases also when a is regular fnko a coincides with chn x the chow group of zero cycles of spec a and cn p coincides with the usual nth chern class as defined by grothendieck see fu when n 3 and a is regular this result was proved in mkm when n 3 and the characteristic of k is not equal to two this result in mkm was extended to the singular case by m levine in this paper we extend the results of mkm to all dimensions with the assumption stated above on torsion in fnko a we first show that cor 3 4 if i c a is a local complete intersection of height n then a i is zero in ko a if and only if i is a complete intersection corollary 3 4 together with a result of mohan kumar mk cor 1 9 here at once gives theorem 3 8 in section 1 we give some preliminaries and generalize results in mk2 these results are crucially used in the rest of the paper the basic ideas in section 1 are all taken from mk2 in section 2 we prove theorem 2 2 which strengthens a result of boratynski bo for local complete intersections with trivial co normal bundle theorem 2 2 is one of the crucial ingredients in the proofs of the results in section 3 as an amusing application of theorem 2 2 we give a new proof of a theorem of srinivas sr about torsion in zero cycles

affine representability results in mathbb a 1 homotopy theory i vector bundles we establish a general affine representability result in a1 homotopy theory over a general base we apply this result to obtain representability results for vector bundles in a1 homotopy theory our results simplify and significantly generalize morel s a1 representability theorem for vector bundles

murthy s conjecture on 0 cycles we show that the levine weibel chow group of 0 cycles mathrm ch d a of a reduced affine algebra a of dimension d ge 2 over an algebraically closed field is torsion free among several applications it implies an affirmative solution to an old conjecture of murthy in classical k theory

modeling stochastic frontier based on vine copulas abstract this article models a production function and analyzes the technical efficiency of listed companies in the united states germany and england between 2005 and 2012 based on the vine copula approach traditional estimates of the stochastic frontier assume that data is multivariate normally distributed and there is no source of asymmetry the proposed method based on vine copulas allow us to explore different types of asymmetry and multivariate distribution using data on product capital and labor we measure the relative efficiency of the vine production function and estimate the coefficient used in the stochastic frontier literature for comparison purposes this production vine copula predicts the value added by firms with given capital and labor in a probabilistic way it thereby stands in sharp contrast to the production function where the output of firms is completely deterministic the results show that on average s p500 companies are more efficient than companies listed in england and germany which presented similar average efficiency coefficients for comparative purposes the traditional stochastic frontier was estimated and the results showed discrepancies between the coefficients obtained by the application of the two methods traditional and frontier vine opening new paths of non linear research

on the max contraction powers of a fuzzy matrix abstract in the literature the powers of a fuzzy matrix with max arithmetic mean convex combination of max min and max arithmetic mean convex combination of max product and max min compositions have been studied it turns out that the limiting behavior of the powers of a fuzzy matrix depends on the composition involved in this paper we consider the max contraction powers of a fuzzy matrix which is an extension of the max arithmetic mean convex combination of max min and max arithmetic mean convex combination of max product and max arithmetic mean operation we show that the powers of such a fuzzy matrix are always convergent and the limit matrix has the feature that all elements of each column are identical

convergence of powers for a fuzzy matrix with convex combination of max min and max arithmetic mean operations fuzzy matrices have been proposed to represent fuzzy relations on finite universes since thomason s paper in 1977 showing that powers of a max min fuzzy matrix either converge or oscillate with a finite period conditions for limiting behavior of powers of a fuzzy matrix have been studied it turns out that the limiting behavior depends on the algebraic operations employed which usually in the literature includes max min max product max archimedean t norm max t norm max arithmetic mean operations respectively in this paper we consider the powers of a fuzzy matrix with convex combination of max min and max arithmetic mean operations we show that the powers of such a fuzzy matrix are always convergent

on the estimation of technical inefficiency in the stochastic frontier production function model abstract the error term in the stochastic frontier model is of the form v u where v is a normal error term representing pure randomness and u is a non negative error term representing technical inefficiency the entire v u is easily estimated for each observation but a previously unsolved problem is how to separate it into its two components v and u this paper suggests a solution to this problem by considering the expected value of u conditional on v u an explicit formula is given for the half normal and exponential cases

euler class groups and the homology of elementary and special linear groups abstract we improve homology stability ranges for elementary and special linear groups over rings with many units our result implies stability for unstable quillen k groups and proves a conjecture of bass for commutative local rings with infinite residue fields we show that the obstruction to further stability is given by milnor witt k theory as an application we construct euler classes of projective modules with values in the cohomology of the milnor witt k theory sheaf for d dimensional commutative noetherian rings with infinite residue fields we show that the vanishing of the euler class is necessary and sufficient for an oriented projective module p of rank d to split off a rank 1 free direct summand along the way we obtain a new presentation of milnor witt k theory and of symplectic k 2 simplifying the classical matsumoto moore presentation

efficiency of thai stock markets detrended fluctuation analysis the evolution of hurst exponent of set index over time as a measure of market efficiency is examined by dfa method it is found that during the study period hurst exponent tends to decrease to the ideal value 0 5 i e the market becomes more efficient this finding readily conforms to the assertion that emerging markets are becoming more efficient additionally the development of hurst exponent during november 2006 to march 2015 of set index compared to mai index is investigated the result shows that the deviation of the hurst exponent from 0 5 for the mai index is larger than that of the set index this implies that set is more efficient than mai and thus supports the assumption that market capitalization has significant influence on market efficiency

convergence of powers of controllable fuzzy matrices abstract convergence of powers of controllable fuzzy matrices is considered it is shown that they oscillate with period equal to 2 in general some equalities and sequences of inequalities about powers of controllable fuzzy matrices are obtained using these general results we improve some results known in the literature

motivic spheres and the image of the suslin hurewicz map we show that an old conjecture of a a suslin characterizing the image of a hurewicz map from quillen k theory in degree n to milnor k theory in degree n admits an interpretation in terms of unstable mathbb a 1 homotopy sheaves of the general linear group using this identification we establish suslin s conjecture in degree 5 for infinite fields having characteristic unequal to 2 or 3 we do this by linking the relevant unstable mathbb a 1 homotopy sheaf of the general linear group to the stable mathbb a 1 homotopy of motivic spheres

the gersten conjecture for milnor k theory we prove that the n th milnor k group of an essentially smooth local ring over an infinite field coincides with the n n motivic cohomology of the ring this implies levine s generalized bloch kato conjecture

on the transitive matrices over distributive lattices abstract a matrix is called a lattice matrix if its elements belong to a distributive lattice for a lattice matrix a of order n if there exists an n n permutation matrix p such that f pap t f ij satisfies f ij f ji for i j then f is called a canonical form of a in this paper the transitivity of powers and the transitive closure of a lattice matrix are studied and the convergence of powers of transitive lattice matrices is considered also the problem of the canonical form of a transitive lattice matrix is further discussed

convergence of products of fuzzy matrices convergence of powers of a fuzzy matrix has been studied in the literature in this paper we shall extend the scope to the products of a finite number of fuzzy matrices we shall demonstrate that the outcomes of products of fuzzy matrices will be more complicated than the cases of powers of a fuzzy matrix two notions of convergence are established weak convergence and strong convergence the main results to guarantee the weak convergence of products of fuzzy matrices are due to the concepts of transitive and compact properties of fuzzy matrices which can be viewed as a generalization of the transitive and compact properties of a fuzzy matrix sufficient conditions similar to the pinching theorem in calculus are given as well for strong convergence

convergence of powers of a fuzzy transitive matrix convergence of powers of a fuzzy transitive matrix is considered and some conditions for convergence are given under the max min operation on fuzzy matrices a fuzzy transitive matrix is a matrix which represents a fuzzy transitive relation and has many interesting properties the conditions for convergence of fuzzy matrices are examined under a special operation which is essential to reduction of fuzzy matrices or fuzzy systems given results show graph theoretic properties of fuzzy matrices and are useful when we consider convergence of systems represented by fuzzy matrices

chow witt groups and grothendieck witt groups of regular schemes let a be a noetherian commutative z 1 2 algebra of krull dimension d and let p be a projective a module of rank d we use derived grothendieck witt groups and euler classes to detect some obstructions for p to split off a free factor of rank one if d 3 we show that the vanishing of its euler class in the corresponding grothendieck witt group is a necessary and sufficient condition for p to have a free factor of rank one if d is odd we also get some results in that direction if a is regular we show that the chow witt groups defined by morel and barge appear naturally as some homology groups of a gersten type complex in grothendieck witt theory from this we deduce that if d 3 then the vanishing of the euler class of p in the corresponding chow witt group is a necessary and sufficient condition for p to have a free factor of rank one crown copyright c 2008 published by elsevier inc all rights reserved