共查询到20条相似文献,搜索用时 15 毫秒
1.
A pair of n×n matrices (A, B) is called a commuting pair if AB=BA. We characterize the linear operators that preserve the set of commuting pairs of matrices over a subsemiring of nonnegative real numbers. 相似文献
2.
The column rank of an m by n matrix A over max algebra is the weak dimension of the column space of A. We compare the column rank with rank of matrices over max algebra. We also characterize the linear operators which preserve the column rank of matrices over max algebra. 相似文献
3.
The column rank of an m by n matrix A over max algebra is the weak dimension of the column space of A. We compare the column rank with rank of matrices over max algebra. We also characterize the linear operators which preserve the column rank of matrices over max algebra. 相似文献
4.
B. Kuzma 《Monatshefte für Mathematik》2003,139(4):271-274
It shown that a linear, surjective mapping which preserves paracontractions in both directions (relative to Euclidean norm) is an (anti)isometry. This is no longer the case if it preserves paracontractions in one direction only.This work was supported by grants from the Ministry of Science and Technology of Slovenia.Received February 4, 2002; in revised form September 20, 2002
Published online May 9, 2003 相似文献
5.
Enrique Casanovas 《Archive for Mathematical Logic》1998,37(4):221-234
A model of countable similarity type and cardinality is expandable if every consistent extension of its complete theory with is satisfiable in and it is compactly expandable if every such extension which additionally is finitely satisfiable in is satisfiable in . In the countable case and in the case of a model of cardinality of a superstable theory without the finite cover property the notions of saturation, expandability and compactness for expandability
agree. The question of the existence of compactly expandable models which are not expandable is open. Here we present a test
which serves to prove that a compactly expandable model of cardinality of a superstable theory is expandable. It is stated in terms of the existence of a certain elementary submodel whose corresponding
theory of pairs of models satisfies a weak elimination of Ramsey quantifiers.
Received May 20, 1996 相似文献
6.
7.
Toshiyasu Arai 《Archive for Mathematical Logic》1998,37(3):149-165
We show that the consistency of the first order arithmetic follows from the pointwise induction up to the Howard ordinal. Our proof differs from U. Schmerl [Sc]: We do not need Girard's
Hierarchy Comparison Theorem. A modification on the ordinal assignment to proofs by Gentzen and Takeuti [T] is made so that
one step reduction on proofs exactly corresponds to the stepping down in ordinals. Also a generalization to theories of finitely iterated inductive definitions is proved.
Received May 30, 1996 相似文献
8.
Summary. In the fields like Astronomy and Ecology, the need for proper statistical analysis of data that are censored is being increasingly
recognized. Such data occur when, due to noise or other factors, instruments fail to detect low luminosities of celestial
objects, or low concentrations of certain pollutants. For multivariate censored data sets there are very few distribution
free methods available and researchers in the various fields often impose an assumption on the joint distribution, such as
multivariate normality, and carry out parametric inferences. Under censoring, however, such parametric inferences are asymptotically
wrong if the imposed assumption is incorrect. In this paper we propose a class of goodness-of-fit procedures for testing assumptions
about the multivariate distribution under random censoring. The test procedures generalize Pearson's goodness-of-fit test
in the sense that they are based on the concept of observed-minus-expected frequencies. The theory of the test statistic,
however, differs from that for the classical Pearson test due to the accommodation of censored data.
Received: 24 May 1994 / In revised form: 3 March 1996 相似文献
9.
《Linear and Multilinear Algebra》2007,55(6):521-533
For each k≥ 0, those nonsingular matrices that transform the set of totally nonzero vectors with k sign variations into (respectively, onto) itself are studied. Necessary and sufficient conditions are provided. The cases k=0,1,2,n-3,n-2,n-1 are completely characterized. 相似文献
10.
Ana Colubi Miguel López-Díiaz J. Santos Domíinguez-Menchero M. Angeles Gil 《Probability Theory and Related Fields》1999,114(3):401-417
Strong laws of large numbers have been stated in the literature for measurable functions taking on values on different spaces.
In this paper, a strong law of large numbers which generalizes some previous ones (like those for real-valued random variables
and compact random sets) is established. This law is an example of a strong law of large numbers for Borel measurable nonseparably
valued elements of a metric space.
Received: 24 February 1998 / Revised version: 3 January 1999 相似文献
11.
Oleg T. Izhboldin 《manuscripta mathematica》2000,102(1):41-52
Let F be a field of characteristic ≠2 and φ be a quadratic form over F. By X
φ we denote the projective variety given by the equation φ=0. For each positive even integer d≥8 (except for d=12) we construct a field F and a pair φ, ψ of anisotropic d-dimensional forms over F such that the Chow motives of X
φ and X
ψ coincide but . For a pair of anisotropic (2
n
-1)-dimensional quadrics X and Y, we prove that existence of a rational morphism Y→X is equivalent to existence of a rational morphism Y→X.
Received: 27 September 1999 / Revised version: 27 December 1999 相似文献
12.
We give a sufficient condition for the inexpressibility of the k-th extended vectorization of a generalized quantifier in , the extension of first-order logic by all k-ary quantifiers. The condition is based on a model construction which, given two -equivalent models with certain additional structure, yields a pair of -equivalent models. We also consider some applications of this condition to quantifiers that correspond to graph properties,
such as connectivity and planarity.
Received: 15 October 1996 相似文献
13.
For arbitrary finite group and countable Dedekind domain such that the residue field is finite for every maximal -ideal , we show that the localizations at every maximal ideal of two -lattices are isomorphic if and only if the two lattices satisfy the same first order sentences. Then we investigate generalizations
of the above results to arbitrary -torsion-free -modules and we apply the previous results to show the decidability of the theory of -lattices. Eventually, we show that -lattices have undecidable theory.
Received November 28, 1995 相似文献
14.
Arthur W. Apter 《Archive for Mathematical Logic》2000,39(3):209-211
We give a new proof using iterated Prikry forcing of Magidor's theorem that it is consistent to assume that the least strongly
compact cardinal is the least supercompact cardinal.
Received: 8 December 1997 / Revised version: 12 November 1998 相似文献
15.
We study some discrete isoperimetric and Poincaré-type inequalities for product probability measures μ
n
on the discrete cube {0, 1}
n
and on the lattice Z
n
. In particular we prove sharp lower estimates for the product measures of boundaries of arbitrary sets in the discrete cube.
More generally, we characterize those probability distributions μ on Z which satisfy these inequalities on Z
n
. The class of these distributions can be described by a certain class of monotone transforms of the two-sided exponential
measure. A similar characterization of distributions on R which satisfy Poincaré inequalities on the class of convex functions is proved in terms of variances of suprema of linear
processes.
Received: 30 April 1997 / Revised version: 5 June 1998 相似文献
16.
Paul Corazza 《Archive for Mathematical Logic》2000,39(3):219-226
The Wholeness Axiom (WA) is an axiom schema that can be added to the axioms of ZFC in an extended language , and that asserts the existence of a nontrivial elementary embedding . The well-known inconsistency proofs are avoided by omitting from the schema all instances of Replacement for j-formulas. We show that the theory ZFC + V = HOD + WA is consistent relative to the existence of an embedding. This answers a question about the existence of Laver sequences for regular classes of set embeddings: Assuming there is an -embedding, there is a transitive model of ZFC +WA + “there is a regular class of embeddings that admits no Laver sequence.”
Received: 7 July 1998 / Revised version: 5 November 1998 相似文献
17.
Kyriakos Keremedis 《Archive for Mathematical Logic》1999,38(3):153-162
We find a characterization of the covering number , of the real line in terms of trees. We also show that the cofinality of is greater than or equal to for every where ( is the additivity number of the ideal of all Lebesgue measure zero sets) is the least cardinal number k for which the statement: fails.
Received: 19 October 1994 / Revised version: 12 December 1996 相似文献
18.
The subject of this paper is a characterization of the -definable set functions of Kripke-Platek set theory with infinity and a uniform version of axiom of choice: . This class of functions is shown to coincide with the collection of set functionals of type 1 primitive recursive in a
given choice functional and . This goal is achieved by a G?del Dialectica-style functional interpretation of and a computability proof for the involved functionals.
Received October 9, 1996 相似文献
19.
We investigate several versions of a cardinal characteristic defined by Frankiewicz. Vojtáš showed , and Blass showed . We show that all the versions coincide and that is greater than or equal to the splitting number. We prove the consistency of and of .
Received: 2 October 1996 / Revised version: 22 May 1997 相似文献
20.
Under rather general assumptions we give an upper and lower bound estimate of the Hausdorff dimension of the invariant probability
measure for an iterated function systems acting on a Polish space.
Received: May 2, 2001; in final form: July 30, 2001?Published online: May 29, 2002 相似文献