bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hyperlinear and Sofic Groups: A Brief Guide
Authors: Pestov Vladimir G. 
Published: January 2009

AbstractThis is an introductory survey of the emerging theory of two new classes of (discrete, countable) groups, called hyperlinear and sofic groups. They can be characterized as subgroups of metric ultraproducts of families of, respectively, unitary groups U(n) and symmetric groups Sn, n ∈ ℕ. Hyperlinear groups come from theory of operator algebras (Connes' Embedding Problem), while sofic groups, introduced by Gromov, are motivated by a problem of symbolic dynamics (Gottschalk's Surjunctivity Conjecture). Open questions are numerous, in particular it is still unknown if every group is hyperlinear and/or sofic.
Full Development of Tarski's Geometry of Solids
Authors: Gruszczyński Rafaŀ , Pietruszczak Andrzej 
Published: January 2009

AbstractIn this paper we give probably an exhaustive analysis of the geometry of solids which was sketched by Tarski in his short paper [20, 21]. We show that in order to prove theorems stated in [20, 21] one must enrich Tarski's theory with a new postulate asserting that the universe of discourse of the geometry of solids coincides with arbitrary mereological sums of balls, i.e., with solids. We show that once having adopted such a solution Tarski's Postulate 4 can be omitted, together with its versions 4′ and 4″. We also prove that the equivalence of postulates 4, 4′ and 4″ is not provable in any theory whose domain contains objects other than solids. Moreover, we show that the concentricity relation as defined by Tarski must be transitive in the largest class of structures satisfying Tarski's axioms.We build a model (in three-dimensional Euclidean space) of the theory of so called T*-structures and present the proof of the fact that this is the only (up to isomorphism) model of this theory.Moreover, we propose different categorical axiomatizations of the geometry of solids. In the final part of the paper we answer the question concerning the logical status (within the theory of T*-structures) of the definition of the concentricity relation given by Tarski.
A Survey of Propositional Realizability Logic
Authors: Plisko Valery 
Published: January 2009

AbstractThe study of propositional realizability logic was initiated in the 50th of the last century. Some interesting results were obtained in the 60-70th, but many important problems in this area are still open. Now interest to these problems from new generation of researchers is observed. This survey contains an exposition of the results on propositional realizability logic and corresponding techniques. Thus reading this paper can be the start point in exploring and development of constructive logic.
Actions of Groups of Finite Morley Rank on Small Abelian Groups
Authors: Deloro Adrien 
Published: January 2009

AbstractWe classify actions of groups of finite Morley rank on abelian groups of Morley rank 2: there are essentially two, namely the natural actions ofSL(V)andGL(V)withVa vector space of dimension 2. We also prove an identification theorem for the natural module of SL2in the finite Morley rank category.
Creatures on ω1 and weak diamonds
Authors: Mildenberger Heike 
Published: January 2009

AbstractWe specialise Aronszajn trees by an ωω-bounding forcing that adds reals. We work with creature forcings on uncountable spaces.As an application of these notions of forcing, we answer a question of Moore, Hrušák and Džamonja whether implies the existence of a Souslin tree in a negative way by showing that “ and every Aronszajn tree is special” is consistent relative to ZFC.
Normal subgroups of infinite symmetric groups, with an application to stratified set theory
Authors: Bowler Nathan , Forster Thomas 
Published: January 2009

It is generally known that infinite symmetric groups have few nontrivial normal subgroups (typically only the subgroups of bounded support) and none of small index. (We will explain later exactly what we mean by small). However the standard analysis relies heavily on the axiom of choice. By dint of a lot of combinatorics we have been able to dispense—largely—with the axiom of choice. Largely, but not entirely: our result is that if X is an infinite set with ∣X∣ = ∣X × X∣ then Symm(X) has no nontrivial normal subgroups of small index. Some condition like this is needed because of the work of Sam Tarzi who showed [4] that, for any finite group G, there is a model of ZF without AC in which there is a set X with Symm(X)/FSymm(X) isomorphic to G.The proof proceeds in two stages. We consider a particularly useful class of permutations, which we call the class of flexible permutations. A permutation of X is flexible if it fixes at least ∣X∣-many points. First we show that every normal subgroup of Symm(X) (of small index) must contain every flexible permutation. This will be theorem 4. Then we show (theorem 7) that the flexible permutations generate Symm(X).
Borel-amenable reducibilities for sets of reals
Authors: Ros Luca Motto 
Published: January 2009

AbstractWe show that if ℱ is any “well-behaved” subset of the Borel functions and we assume the Axiom of Determinacy then the hierarchy of degrees on (ωω) induced by ℱ turns out to look like the Wadge hierarchy (which is the special case where ℱ is the set of continuous functions).
Decisive creatures and large continuum
Authors: Kellner Jakob , Shelah Saharon 
Published: January 2009

AbstractFor f, g ∈ ωω let be the minimal number of uniform g-splitting trees (or: Slaloms) to cover the uniform f-splitting tree, i.e., for every branch v of the f-tree, one of the g-trees contains v. is the dual notion: For every branch v, one of the g-trees guesses v(m) infinitely often.It is consistent that for ℵ1 many pairwise different cardinals κ∊ and suitable pairs (f∊, g∊).For the proof we use creatures with sufficient bigness and halving. We show that the lim-inf creature forcing satisfies fusion and pure decision. We introduce decisiveness and use it to construct a variant of the countable support iteration of such forcings, which still satisfies fusion and pure decision.
Zero-one law and definability of linear order
Authors: Niemistö Hannu 
Published: January 2009

§1. Introduction. A logic ℒ has a limit law, if the asymptotic probability of every query definable in ℒ converges. It has a 0–1-law if the probability converges to 0 or 1. The 0–1-law for first-order logic on relational vocabularies was independently found by Glebski et al. [6] and Fagin [5]. Later it has been shown for many other logics, for instance for fragments of second order logic [12], for finite variable logic [13] and for FO extended with the rigidity quantifier [3]. Lynch [14] has shown a limit law for first-order logic on vocabularies with unary functions.We say that two formulas or two logics are almost everywhere equivalent, if they are equivalent on a class of structures whose asymptotic probability measure is one [7]. A 0–1-law is usually proved by showing that every quantifier of the logic has almost everywhere quantifier elimination, i.e., every formula with just one quantifier in front of it is almost everywhere equivalent to a quantifier-free formula. Besides proving 0–1-law, this implies that the logic is (weakly) almost everywhere equivalent to first-order logic.The aim of this paper is to study, whether a logic with a 0–1-law can have greater expressive power than FO in the almost everywhere sense and to what extent. In particular, we are interested on the definability of linear order. Because a 0–1-law determines the almost everywhere expressive power of the sentences of the logic completely, but does not say anything about formulas explicitly, we have to assume some regularity on logics. We will therefore mostly consider extensions of first-order logic with generalized quantifiers.
From index sets to randomness in ∅n: random reals and possibly infinite computations part II
Authors: Becher Verónica , Grigorieff Serge 
Published: January 2009

AbstractWe obtain a large class of significant examples ofn-random reals (i.e., Martin-Löf random in oracle ∅(n−1)) à la Chaitin. Any such real is defined as the probability that a universal monotone Turing machine performing possibly infinite computations on infinite (resp. finite large enough, resp. finite self-delimited) inputs produces an output in a given set. In particular, we develop methods to transfermany-one completeness results of index sets ton-randomness of associated probabilities.
On second order intuitionistic propositional logic without a universal quantifier
Authors: Zdanowski Konrad 
Published: January 2009

AbstractWe examine second order intuitionistic propositional logic, IPC2. Let ℱ∃ a be the set of formulas with no universal quantification. We prove Glivenko's theorem for formulas in ℱ∃ that is, for φ ∈ ℱ∃, φ is a classical tautology if and only if ┐┐φ is a tautology of IPC2. We show that for each sentence φ ∈ ℱ∃ (without free variables), φ is a classical tautology if and only if φ is an intuitionistic tautology. As a corollary we obtain a semantic argument that the quantifier ∀ is not definable in IPC2 from ⊥, ⋁, ⋀, →, ∃.
Towards a characterization of order-invariant queries over tame graphs
Authors: Benedikt Michael , Segoufin Luc 
Published: January 2009

AbstractThis work deals with the expressive power of logics on finite graphs with access to an additional “arbitrary” linear order. The queries that can be expressed this way are the order-invariant queries for the logic. For the standard logics used in computer science, such as first-order logic, it is known that access to an arbitrary linear order increases the expressiveness of the logic. However, when we look at the separating examples, we find that they have satisfying models whose Gaifman Graph is complex – unbounded in valence and in treewidth. We thus explore the expressiveness of order-invariant queries over well-behaved graphs. We prove that first-order order-invariant queries over strings and trees have no additional expressiveness over first-order logic in the original signature. We also prove new upper bounds on order-invariant queries over bounded treewidth and bounded valence graphs. Our results make use of a new technique of independent interest: the application of algebraic characterizations of definability to show collapse results.
Increasing u2 by a stationary set preserving forcing
Authors: Claverie Benjamin , Schindler Ralf 
Published: January 2009

AbstractWe show that if I is a precipitous ideal on ω1 and if θ > ω1 is a regular cardinal, then there is a forcing ℙ = ℙ(I, θ) which preserves the stationarity of all I-positive sets such that in Vℙ, ⟨Hθ; ∈, I⟩ is a generic iterate of a countable structure ⟨M; ∈, Ī⟩. This shows that if the nonstationary ideal on ω1 is precipitous and exists, then there is a stationary set preserving forcing which increases . Moreover, if Bounded Martin's Maximum holds and the nonstationary ideal on ω1 is precipitous, then .
An inner model for global domination
Authors: Friedman Sy-David , Thompson Katherine 
Published: January 2009

AbstractIn this paper it is shown that the global statement that the dominating number for κ is less than 2κ for all regular κ, is internally consistent, given the existence of 0#. The possible range of values for the dominating number for κ and 2κ which may be simultaneously true in an inner model is also explored.
Arithmetic on semigroups
Authors: Ganea Mihai 
Published: January 2009

AbstractRelations between some theories of semigroups (also known as theories of strings or theories of concatenation) and arithmetic are surveyed. In particular Robinson's arithmetic Q is shown to be mutually interpretable with TC, a weak theory of concatenation introduced by Grzegorczyk. Furthermore, TC is shown to be interpretable in the theory F studied by Tarski and Szmielewa, thus confirming their claim that F is essentially undecidable.
PDL with intersection and converse: satisfiability and infinite-state model checking
Authors: Stefan Göller  , Lohrey Markus , Lutz Carsten 
Published: January 2009

AbstractWe study satisfiability and infinite-state model checking in ICPDL, which extends Propositional Dynamic Logic (PDL) with intersection and converse operators on programs. The two main results of this paper are that (i) satisfiability is in 2ΕΧΡΤΙΜΕ, thus 2ΕΧΡΤΙΜΕ-complete by an existing lower bound, and (ii) infinite-state model checking of basic process algebras and pushdown systems is also 2ΕΧΡΤΙΜΕ-complete. Both upper bounds are obtained by polynomial time computable reductions to ω-regular tree satisfiability in ICPDL, a reasoning problem that we introduce specifically for this purpose. This problem is then reduced to the emptiness problem for alternating two-way automata on infinite trees. Our approach to (i) also provides a shorter and more elegant proof of Danecki's difficult result that satisfiability in IPDL is in 2ΕΧΡΤΙΜΕ. We prove the lower bound(s) for infinite-state model checking using an encoding of alternating Turing machines.
Stacking mice
Authors: Jensen Ronald , Schimmerling Ernest , Schindler Ralf , Steel John 
Published: January 2009

AbstractWe show that either of the following hypotheses imply that there is an inner model with a proper class of strong cardinals and a proper class of Woodin cardinals. 1) There is a countably closed cardinal κ ≥ ℵ such that □κ and □(κ) fail. 2) There is a cardinal κ such that κ is weakly compact in the generic extension by Col(κ, κ+). Of special interest is 1) with κ = ℵ3 since it follows from PFA by theorems of Todorcevic and Velickovic. Our main new technical result, which is due to the first author, is a weak covering theorem for the model obtained by stacking mice over Kc∥κ.
Prime models of finite computable dimension
Authors: Semukhin Pavel 
Published: January 2009

AbstractWe study the following open question in computable model theory: does there exist a structure of computable dimension two which is the prime model of its first-order theory? We construct an example of such a structure by coding a certain family of c.e. sets with exactly two one-to-one computable enumerations into a directed graph. We also show that there are examples of such structures in the classes of undirected graphs, partial orders, lattices, and integral domains.
Finding paths through narrow and wide trees
Authors: Binns Stephen , Kjos-Hanssen Bjørn 
Published: January 2009

AbstractWe consider two axioms of second-order arithmetic. These axioms assert, in two different ways, that infinite but narrow binary trees always have infinite paths. We show that both axioms are strictly weaker than Weak König's Lemma, and incomparable in strength to the dual statement (WWKL) that wide binary trees have paths.
Impact of Communicating Familial Risk of Diabetes on Illness Perceptions and Self-Reported Behavioral Outcomes
Authors: Pijl Miranda , Timmermans Danielle R.M. , Claassen Liesbeth , Janssens A. Cecile J.W. , Nijpels Giel , Dekker Jacqueline M. , Marteau Theresa M. , Henneman Lidewij 
Published: January 2009

OBJECTIVE
To assess the potential effectiveness of communicating familial risk of diabetes on illness perceptions and self-reported behavioral outcomes.

RESEARCH DESIGN AND METHODS
Individuals with a family history of diabetes were randomized to receive risk information based on familial and general risk factors (n = 59) or general risk factors alone (n = 59). Outcomes were assessed using questionnaires at baseline, 1 week, and 3 months.

RESULTS
Compared with individuals receiving general risk information, those receiving familial risk information perceived heredity to be a more important cause of diabetes (P &lt; 0.01) at 1-week follow-up, perceived greater control over preventing diabetes (P &lt; 0.05), and reported having eaten more healthily (P = 0.01) after 3 months. Behavioral intentions did not differ between the groups.

CONCLUSIONS
Communicating familial risk increased personal control and, thus, did not result in fatalism. Although the intervention did not influence intentions to change behavior, there was some evidence to suggest it increases healthy behavior.
Combined Measurement of Fasting Plasma Glucose and A1C Is Effective for the Prediction of Type 2 Diabetes
Authors: Sato Kyoko Kogawa , Hayashi Tomoshige , Harita Nobuko , Yoneda Takeshi , Nakamura Yoshiko , Endo Ginji , Kambe Hiroshi 
Published: January 2009

OBJECTIVE
We prospectively assessed whether the combined measurements of fasting plasma glucose (FPG) and A1C were effective for predicting type 2 diabetes.

RESEARCH DESIGN AND METHODS
Study participants included 6,736 nondiabetic Japanese men aged 40–55 years. Type 2 diabetes was diagnosed in those who had an FPG ≥126 mg/dl or who were being treated with an oral antidiabetic agent or insulin. The models including FPG, A1C, and both were compared using the area under the receiver operating characteristic (AUROC) curves.

RESULTS
During the 4-year follow-up period, we confirmed 659 diabetes cases. In multivariate analysis, both FPG and A1C were independently associated with the risk of type 2 diabetes. The model including both FPG and A1C had a greater AUROC curve than that including FPG alone (0.853 vs. 0.818; P &lt; 0.001) or A1C alone (0.853 vs. 0.771; P &lt; 0.001).

CONCLUSIONS
The combined measurement of FPG and A1C was effective for predicting type 2 diabetes.
Admission Hyperglycemia Predicts a Worse Outcome in Stroke Patients Treated With Intravenous Thrombolysis
Authors: Poppe Alexandre Y. , Majumdar Sumit R. , Jeerakathil Thomas , Ghali William , Buchan Alastair M. , Hill Michael D. 
Published: January 2009

OBJECTIVE
Admission hyperglycemia has been associated with worse outcomes in ischemic stroke. We hypothesized that hyperglycemia (glucose &gt;8.0 mmol/l) in the hyperacute phase would be independently associated with increased mortality, symptomatic intracerebral hemorrhage (SICH), and poor functional status at 90 days in stroke patients treated with intravenous tissue plasminogen activator (IV-tPA).

RESEARCH DESIGN AND METHODS
Using data from the prospective, multicenter Canadian Alteplase for Stroke Effectiveness Study (CASES), the association between admission glucose &gt;8.0 mmol/l and mortality, SICH, and poor functional status at 90 days (modified Rankin Scale &gt;1) was examined. Similar analyses examining glucose as a continuous measure were conducted.

RESULTS
Of 1,098 patients, 296 (27%) had admission hyperglycemia, including 18% of those without diabetes and 70% of those with diabetes. After multivariable logistic regression, admission hyperglycemia was found to be independently associated with increased risk of death (adjusted risk ratio 1.5 [95% CI 1.2–1.9]), SICH (1.69 [0.95–3.00]), and a decreased probability of a favorable outcome at 90 days (0.7 [0.5–0.9]). An incremental risk of death and SICH and unfavorable 90-day outcomes was observed with increasing admission glucose. This observation held true for patients with and without diabetes.

CONCLUSIONS
In this cohort of IV-tPA–treated stroke patients, admission hyperglycemia was independently associated with increased risk of death, SICH, and poor functional status at 90 days. Treatment trials continue to be urgently needed to determine whether this is a modifiable risk factor for poor outcome.
Halphen pencils on weighted Fano threefold hypersurfaces
Authors: Cheltsov Ivan , Park Jihun 
Published: January 2009

AbstractOn a general quasismooth well-formed weighted hypersurface of degree Σi=14 a i in ℙ(1, a 1, a 2, a 3, a 4), we classify all pencils whose general members are surfaces of Kodaira dimension zero.
On the solutions of Knizhnik-Zamolodchikov system
Authors: Sakhnovich Lev 
Published: January 2009

AbstractWe consider the Knizhnik-Zamolodchikov system of linear differential equations. The coefficients of this system are rational functions. We prove that under some conditions the solution of the KZ system is rational too. We give the method of constructing the corresponding rational solution. We deduce the asymptotic formulas for the solution of the KZ system when the parameter ρ is an integer.
Executive dysfunction in a survival environment
Authors: Porter Heather , Leach John 
Published: January 2009

AbstractVictims often respond to survival incidents with maladaptive behaviours that suggest impairment in executive function. To examine this hypothesis the authors tested sub‐components of executive function during an intensive military survival exercise. Compared to a control group the survival course participants showed significant impairment in the incongruent condition of the Stroop task; the mean repetition gap and adjacent letter pair components of the random letter generation task; and the planning and action components of the Tower of London task. No impairment was found in dual‐task performance nor in verbal fluency. The pattern of the data suggests that the maladaptive behaviour frequently observed in survival incidents may be explained by dysfunction in the supervisory system‐contention scheduler interface. Copyright © 2009 John Wiley & Sons, Ltd.
Zweidimensionale Polymere: nur ein Traum von Synthetikern?
Authors: Sakamoto Junji , van Heijst Jeroen , Lukin Oleg , Schlüter A. Dieter 
Published: January 2009

AbstractVermutlich werden synthetische 2D‐Polymere auf vielen Gebieten der Naturwissenschaft und Technik Bedeutung erlangen, und zwar grundlegende ebenso wie praktische. Daher überrascht es, dass auf diesem Gebiet bisher so wenige Fortschritte zu verzeichnen sind. In den letzten Jahrzehnten sind zwar viele Ansätze zur Synthese solcher Polymere beschrieben worden, die tatsächliche Synthese eines kovalent verknüpften, periodischen, molekularen Films mit der Dicke einer Monomereinheit ist bisher jedoch nicht gelungen. Unser Aufsatz liefert einen Überblick über bisherige Strategien sowie eine Analyse, wie die Synthese eines 2D‐Polymers wohl gelingen könnte. Bei unserer Analyse wird die Polymerisation in einer (anfänglich) homogenen Phase mit der Polymerisation an Grenzflächen verglichen, und es werden strukturelle Aspekte von Monomeren sowie möglicherweise bevorzugte Verknüpfungsmodi berücksichtigt. Es werden auch Aspekte wie Schrumpfung sowie Domänen‐ und Rissbildung behandelt, und es wird kurz darauf eingegangen, wie die Chancen für eine erfolgreiche Strukturanalyse des Endprodukts verbessert werden könnten.
Structural and Electronic Properties of Ultrathin Tin–Phthalocyanine Films on Ag(111) at the Single‐Molecule Level
Authors: Wang Yongfeng , Kröger Jörg , Berndt Richard , Hofer Werner 
Published: January 2009

AbstractKopf oder Zahl? Die Entwicklung der strukturellen und elektronischen Eigenschaften von Zinn‐Phthalocyanin‐Filmen wurde von einer Submonoschicht‐ bis zu einer Multischichtbedeckung mithilfe der Niedertemperatur‐Rastertunnelmikroskopie analysiert. Zwei Molekülkonformationen wurden beobachtet: zufällig verteilt in der ersten Schicht und als Inseln mit einer einzigen Konformation in den folgenden Schichten.magnified image
A Two‐State Reactivity Model Explains Unusual Kinetic Isotope Effect Patterns in CH Bond Cleavage by Nonheme Oxoiron(IV) Complexes
Authors: Klinker Eric J. , Shaik Sason , Hirao Hajime , Que Lawrence 
Published: January 2009

AbstractDie Bindungsstärke zählt: Die Werte für den kinetischen Isotopeneffekt (KIE) bei der Spaltung von C‐H‐Bindungen durch zwei verwandte Oxoeisen(IV)‐Komplexe zeigen eine ungewöhnliche Abhängigkeit von der C‐H‐Bindungsstärke: Große, nichtklassische KIE‐Werte treten bei Bindungsstärken unter 93 kcal mol−1 auf, semiklassische Werte darüber (siehe Bild; DHA=9,10‐Dihydroanthracen). Dieses unerwartete Verhalten lässt sich mithilfe eines Zwei‐Zustands‐Reaktivitätsmodells verstehen.magnified image