arXiv subjects

Boaz Tsaban

Publications and source records attributed to Boaz Tsaban.

At least 127 records · Page 7Linked to original sources

arXiv2007

SPM Bulletin 20

This issue contains announcements of articles on: The Pytkeev property; Partial order embeddings; Resolvability; Singular density; P(w)/fin and the Calkin algebra; Everywhere meagre and everywhere null sets; almost disjoint families; forcing axioms; Splitting families; Sacks Reals; unconditionally closed and algebraic sets in groups; Stratifiability; Dissipated Compacta; partition relations; pi-bases; covering by translates of a compact nullsets; and a new Problem of the Issue.

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arXiv2006

SPM Bulletin 19

Contents of the issue: Selection Principles and special sets of reals: Open problems Winning the pressing down game but not Banach Mazur Ramsey classes of topological and metric spaces More on partitioning triples of countable ordinals Countable compact Hausdorff spaces need not be metrizable in ZF Every topological group is a group retract of a minimal group The complexity of classifying separable Banach spaces up to isomorphism Reals n-generic relative to some perfect tree Nagata's conjecture and countably compactifications in generic extensions A Class of Groups in Which All Unconditionally Closed Sets are Algebraic A c0-saturated Banach space with no long unconditional basic sequences Spaces of continuous functions over Dugundji compacta Varia: Ideals and Equivalence Relations, beta-version Equivariant embedding of metrizable G-spaces in linear G-spaces Squares of Menger-bounded groups kappa-Frechet-Urysohn property of Ck(X) How to drive our families mad Hurewicz sets of reals without perfect subsets The spectrum of characters of ultrafilters on w Spaces of functions with countably many discontinuities Can groupwise density be much bigger than the non-dominating number? Productive local properties of function spaces Pinning quasi orders with their endomorphisms A game on the universe of sets Algebraic characterizations of measure algebras

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arXiv2006

SPM Bulletin 17

CONTENTS: Lecce Workshop presentations available online; Borel cardinalities below c_0; Hereditarily non-topologizable groups; A hodgepodge of sets of reals; Random gaps; Covering a bounded set of functions by an increasing chain of slaloms; Baire-one mappings contained in a usco map; Applications of k-covers II; Additivity numbers of covering properties; Combinatorial images of sets of reals and semifilter trichotomy; Another algebraic equivalent of the Continuum Hypothesis; A connection between decomposable ultrafilters and possible cofinalities II; Game Approach to Universally Kuratowski-Ulam Spaces; On the density of Banach spaces C(K) with the Grothendieck property; Antichains in partially ordered sets of singular cofinality; Bolzano-Weierstrass principle of choice extended towards ordinals; Nonequality of Dimensions for Metric Groups; Not all pure states on B(H) are diagonalizable; A comment on p<t; Problem of the Issue.

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arXiv2006

SPM Bulletin 16

CONTENTS OF THE ISSUE: Hurewicz-like tests for Borel subsets of the plane; Ordered Spaces, Metric Preimages, and Function Algebras; On the independence of a generalized statement of Egoroff's theorem from ZFC, after T. Weiss; Forty annotated questions about large topological groups; Strong compactness and a partition property; Countable Borel equivalence relations and quotient Borel spaces; Decisive creatures and large continuum; Models of real-valued measurability; Hausdorff ultrafilters; Block combinatorics; Maharam's problem; Universality of uniform Eberlein compacta; Linearly ordered compacta and Banach spaces with a projectional resolution of the identity; Steinhaus Sets and Jackson Sets; Problem of the Issue; Problems from earlier issues.

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arXiv2005

SPM Bulletin 15

CONTENTS: On Selective screenability and examples of R. Pol. Workshops and conferences: The Oxford Conference on Topology and Computer Science in Honour of Peter Collins and Mike Reed; Boise Extravaganza In Set Theory (BEST2006). Research announcements: The isometry group of the Urysohn space as a Levy group; Chasing Silver; Disjoint Non-Free Subgoups of Abelian Groups; Characterizing metric spaces whose hyperspaces are absolute neighborhood retracts; A Vitali set can be homeomorphic to its complement; o-Boundedness of free objects over a Tychonoff space; On the consistency strength of the Milner-Sauer conjecture; Reconstruction of manifolds and subsets of normed spaces from subgroups of their homeomorphism groups; Reconstruction theorem for homeomorphism groups without small sets and non-shrinking functions of a normed space; Locally Moving Groups and the Reconstruction Problem for Chains and Circles; Divisibility of countable metric spaces; Pre-compact families of finite sets of integers and weakly null sequences in Banach spaces; A semifilter approach to selection principles II: tau^*-covers; Parametrizing the abstract Ellentuck theorem; A notion of selective ultrafilter corresponding to topological Ramsey spaces; Compact spaces generated by retractions; Gromov-Hausdorff ultrametric; Computing the complexity of the relation of isometry between separable Banach spaces; On some classes of Lindelöf Sigma-spaces; On the depth of Boolean algebras. Problem of the Issue.

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arXiv2005

SPM Bulletin 14

CONTENTS: New reals: Can live with them, can live without them; Uniform almost everywhere domination; Heredity of tau-pseudocompactness; Understanding preservation theorems: omega^omega-bounding; Classification problems in continuum theory; Residuality of families of F_sigma sets; First countable, countably compact spaces and the continuum hypothesis; Game approach to universally Kuratowski-Ulam spaces; Small Valdivia compact spaces; Canonical forms of Borel functions on the Milliken space; Complete analytic equivalence relations; The Number of Near-Coherence Classes of Ultrafilters is Either Finite or 2^c; The complexity of recursion theoretic games; Cosmic dimension; There is no categorical metric continuum; On a conjecture and a problem of Hurewicz; Problem of the Issue.

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arXiv2005

SPM Bulletin 13

Contents of this issue: Workshops on SPM themes; Second workshop on Coverings, Selections and Games in Topology (SPM05); Analysis and Descriptive Set Theory Workshop; Descriptive set theory: Effective methods, equivalence relations; Analysis: typical functions, level sets structure; Organizational and additional details; Research announcements; Cardinal restrictions on some homogeneous compacta; Filters: Topological congruence relations on groups; Inverse Limits and Function Algebras; Ultrafilters and partial products of infinite cyclic groups; More on regular reduced products; Consistency of ``the ideal of null restricted to some A is kappa-complete not kappa^+-complete, kappa weakly inaccessible and cov(M)=aleph_1''; On removing one point from a compact space; Problems from earlier issues.

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arXiv2005

SPM Bulletin 10

We announce the solution of 4+21+1/2 (!) problems posed in earlier issues of the SPM Bulletin; the ``1/2'' standing for a ``consistently yes'' answer of Zdomsky to the last issue's Problem of the Month.

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arXiv2005

SPM Bulletin 11

This issue contains, in addition to the usual contents, a special festive announcement: A book. This book by Banakh and Zdomsky seems to be the first in a planned series by these authors. We believe that the book will become a cornerstone in many future mathematical investigations, in particular in the field of infinite-combinatorial topology. The book's preliminary version is available online, as seen in the announcement, and the readers of the SPM Bulletin are encouraged to take a look and make comments. Zdomsky has also made two detailed contributions to this issue. This is the ideal form of a contribution to the SPM Bulletin, and we urge all contributors to consider this possibility from time to time. 1 Editor's note; 2 Research announcements; 2.1 On subclasses of weak Asplund spaces; 2.2 The number of translates of a closed nowhere dense set required to cover a Polish group; 2.3 More on convexity numbers of closed sets in R^n; 2.4 A new book: Coherence of Semifilters; 3 Characterization of topological spaces with (strictly) o-bounded free topological group; 4 An equivalent of SPM Bulletin 2's Problem of the month; 5 Boise Extravaganza In Set Theory (March 25--27, 2005); 6 Problem of the Issue; 7 Problems from earlier issues; References

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arXiv2005

SPM Bulletin 12

In this issue we celebrate the appearance of the proceedings of the first SPM Workshop, announce several mathematical breakthroughs, have two extended contributions by Babinkostova, and a new open problem by Kalenda. Contents: Editor's note; Proceedings of the first workshop on Coverings, Selections, and Games in Topology; A five element basis for the uncountable linear orders; Set mapping reflection; The Proper Forcing Axiom, Prikry forcing, and the Singular Cardinals Hypothesis; A solution to the L space problem and related ZFC constructions; Countable Tightness, Elementary Submodels and Homogeneity; No transcendence basis of R over Q can be an analytic set; Two properties of C_p(X) weaker than Fr'echet Urysohn property; Some partition properties for measurable colourings of (\aleph_1)^2; Potential theory and forcing; On decompositions of Banach spaces of continuous functions on Mr'owka's spaces; A note on D-spaces; Set-theoretic properties of Schmidt's ideal; Almost-disjoint coding and strongly saturated ideals; Selective screenability and covering dimension; On a problem of Rothberger and Sierpinski; Problem of the Issue; Problems from earlier issues;

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arXiv2004

The combinatorics of Borel covers

In this paper we extend previous studies of selection principles for families of open covers of sets of real numbers to also include families of countable Borel covers. The main results of the paper could be summarized as follows: 1. Some of the classes which were different for open covers are equal for Borel covers -- Section 1; 2. Some Borel classes coincide with classes that have been studied under a different guise by other authors -- Section 4.

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arXiv2004

SPM Bulletin 9

This is the ninth issue of this bulletin. CONTENTS: Proceedings of SPM Workshop; A brief remark on van der Waerden spaces; Complete ccc Boolean algebras, the order sequential topology, and a problem of von Neumann; Cardinal invariants p, t and h and real functions; A comment on p<t; On squares of spaces and F_sigma-sets; Comparing the uniformity invariants of null sets for different measures; Maximal functions and the additivity of various families of null sets; How many miles to beta(omega)? -- Approximating beta(omega) by metric-dependent compactifications; The cardinal characteristic for relative gamma-sets; Uncountable intersections of open sets under CPA_prism; Covering R^{n+1} by graphs of n-ary functions and long linear orderings of Turing degrees; CONFERENCE: Foundations of the Formal Sciences V: Infinite Games; Problem of the month; Problems from earlier issues

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arXiv2004

SPM Bulletin 8

Never has an issue of the SPM Bulletin contained as much interesting information as this issue does. In addition to the interesting research announcements, this issue contains announcements of solutions for three open problems, one of which being a Problem of the Month in an earlier issue. CONTENTS: The Reznichenko property and the Pytkeev property in hyperspaces; Between Maharam's and von Neumann's problems; Fraisse Limits, Ramsey Theory, and Topological Dynamics of Automorphism Groups; Concerning problems about cardinal invariants on Boolean algebras; Small Locally Compact Linearly Lindelof Spaces; Luzin gaps; The weak Fréchet-Urysohn property in function spaces; $F$-Hurewicz spaces; Open problems in topology; The hyper-weak distributive law and a related game in Boolean algebras; Problem of Issue 7 solved; Errata to: Hereditary topological diagonalizations and the Menger-Hurewicz Conjectures; The additivity number of the Menger and Scheepers properties; Conferences: Geometric Topology: Infinite-Dimensional Topology, Absolute Extensors, Applications; Problem of the month; Problems from earlier issues; References

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arXiv2004

SPM Bulletin 7

This is the seventh issue of this bulletin, featuring a new form as well as a concise list of past open problems.

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arXiv2003

SPM Bulletin 6 (November 2003)

After a long break, we are back with some very interesting research announcements and an open problem which is one of the most difficult, long lasting, and important problems in the field. A major change in this bulletin is that from now on it will usually not appear monthly, but more close to quarterly. Special announcements (if urgent) will be made by text emails. Contributions to the next issue are, as always, welcome.

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arXiv2003

SPM Bulletin 5 (Special issue)

*** Note the comment above *** This is a special issue dedicated to the announcement of Shelah's recent solution of the Minimal Tower problem, one of the oldest and most important problems in infinite combinatorics which also motivated some new studies in SPM (see fourth issue of this bulletin). We give some background and personal perspectives on the problem and its solution. We decided not to include additional research announcements in this issue, so to let them draw the attention they deserve in the coming issue. This issue also contains an interesting new problem which is related to the Minimal Tower problem (but still open).

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arXiv2003

Pseudorandom permutations with the fast forward property

This paper has been withdrawn by the author(s), due to the existence of a much better paper in http://arxiv.org/abs/cs.CR/0207027

cs.CR↗

arXiv2003

Efficient linear feedback shift registers with maximal period

We introduce and analyze an efficient family of linear feedback shift registers (LFSR's) with maximal period. This family is word-oriented and is suitable for implementation in software, thus provides a solution to a recent challenge posed in FSE '94. The classical theory of LFSR's is extended to provide efficient algorithms for generation of irreducible and primitive LFSR's of this new type.

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