We study the notion of weak amalgamation in the context of diagonal conjugacy classes. Generalizing results of Kechris and Rosendal, we prove that for every countable structure M, Polish group G of permutations of M, and \, G has a comeager n-diagonal conjugacy class iff the family of all n-tuples of G-extendable bijections between finitely generated substructures of M, has the joint embedding property and the weak amalgamation property. We characterize limits of weak Fraïssé classes that (...) are not homogenizable. Finally, we investigate 1- and 2-diagonal conjugacy classes in groups of ball-preserving bijections of certain ordered ultrametric spaces. (shrink)

We compare two different notions of generic expansions of countable saturated structures. One kind of genericity is related to existential closure, and another is defined via topological properties and Baire category theory. The second type of genericity was first formulated by Truss for automorphisms. We work with a later generalization, due to Ivanov, to finite tuples of predicates and functions. Let $N$ be a countable saturated model of some complete theory $T$ , and let $(N,\sigma)$ denote an expansion of $N$ (...) to the signature $L_{0}$ which is a model of some universal theory $T_{0}$ . We prove that when all existentially closed models of $T_{0}$ have the same existential theory, $(N,\sigma)$ is Truss generic if and only if $(N,\sigma)$ is an e-atomic model. When $T$ is $\omega$ -categorical and $T_{0}$ has a model companion $T_{\mathrm {mc}}$ , the e-atomic models are simply the atomic models of $T_{\mathrm {mc}}$. (shrink)

The Cherlin–Zil'ber Conjecture states that all simple groups of finite Morley rank are algebraic. We prove that any minimal counterexample to this conjecture has a unique conjugacy class of Carter subgroups, which are analogous to Cartan subgroups in algebraic groups.

We show that every two-dimensional class of topological similarity, and hence every diagonal conjugacy class of pairs, is meager in the group of order preserving bijections of the rationale and in the group of automorphisms of the ordered rational Urysohn space.

Die „Grundlage der gesamten Wissenschaftslehre“ bleibt für den, der Fichte im philosophiegeschichtlichen Zusammenhang sehen will, der wichtigste Text; dies gilt auch dann noch, wenn die Akademie-Ausgabe abgeschlossen sein wird. Der Jenaer Fichte hat nicht nur auf seine Zeitgenossen am stärksten gewirkt, er war auch seinerseits damals noch am offensten für Einflüsse. Der vorliegende Kommentar – der erste, der den gesamten deutschen Text behandelt – bietet keine Paraphrase, keine Übersetzung in eine zeitgemäßere Sprache, keine „Darstellung“, die Fichtes Disposition durch eine eigene (...) ersetzt und damit – gewollt oder ungewollt – in Konkurrenz zum Original tritt. Er will vielmehr den Leser auf seinem dornigen Pfad Satz für Satz begleiten und bei keiner Schwierigkeit im Stich lassen. Die konkrete Erforschung literarischer Bezüge und Abhängigkeiten zeigt, wie sehr der „Selbstdenker“ Fichte – unbeschadet seiner Eigenständigkeit – nicht nur in der Philosophie, sondern im ganzen Geistesleben der Epoche verwurzelt ist. Durch die ausgiebigen, mit sprachlichen Erläuterungen versehenen Zitate entlegener Quellen ist der Kommentar zugleich eine Art Lesebuch. (shrink)

The present "philological commentary" is directed at those who have decided to take time for reading the original text, at least in an English translation. The first volume "Textual Criticism" is intended to meet the difficulties caused by the fact that our text editions are based on manuscripts separated from the original by more than a millennium.

With the third volume, it is invited to enter the intellectual environment of Aristotle. The most relevant sources are given in full (with English translation), so that the commentary is also a reader documenting the disputationes metaphysicae of the 4th century BC. For the undeniable contradictions in the Metaphysics, a new genetic explanation is offered.

Though since Werner Jaeger's famous Studien zur Entstehungsgeschichte der Metaphysik des Aristoteles of 1912 remarkable observations were made, the topic "Composition of the Metaphysics" almost disappeared from the agenda. As, however, neglect of this philological task results in either selective reading or anachronistic systematization, the author has resumed it, extending it to the internal structure of the singular books.

Though since Werner Jaeger's famous Studien zur Entstehungsgeschichte der Metaphysik des Aristoteles of 1912 remarkable observations were made, the topic "Composition of the Metaphysics" almost disappeared from the agenda. As, however, neglect of this philological task results in either selective reading or anachronistic systematization, the author has resumed it, extendig it to the internal structure of the singular books.

The question of the relationship between ontology and theology, the main problem of the interpretation in volume 3, is also the guiding question of our last volume. The history of metaphysics is a history of the efforts towards an outlook on the world and life, which are about the meaning and connection of fundamental concepts: being, life, intellect, unity, truth, goodness. From these, the concept of divinity is derived. As in the previous volumes, a rich material of original texts and (...) interpretations is spread out. (shrink)

Der vorliegende "philologische" Kommentar beansprucht Kants Critik der reinen Vernunft aus ihren historischen Voraussetzungen zu erklären. Zu diesen gehört an erster Stelle Kants Sprache; sie ist nicht mehr die unsere, was den unvorbereiteten Leser von heute schon an der Semantik und Syntax vieler Sätze scheitern lässt. Neben einer Fülle von sprachlichen Erläuterungen und textkritischen Untersuchungen bringt der Kommentar reichliche Zitate aus den von Kant benutzten Logik- und Metaphysik-Lehrbüchern, die seine Rezeption der "dogmatischen" Philosophie Christian Wolffs und seiner Nachfolger belegen; lateinische (...) Texte werden dabei sowohl im Original als auch in deutscher Übersetzung geboten. Einzelne Motive werden ideengeschichtlich bis in die Antike zurückverfolgt; hieraus eröffnen sich Perspektiven für eine "Metakritik" von einem "vorkritischen" Standpunkt aus, die im Rahmen eines philologischen Kommentars nur angedeutet werden können. (shrink)

When a professor from Middle Europe teaches Computer Ethics in the Middle East using a textbook from the US, cultural differences become apparent. A main challenge lies in avoiding cultural imperialism during teaching. In order to meet this challenge, personal portfolios have been used for course work. The course design as well as portfolio tasks are presented and experiences are discussed. Based on our experiences we recommend applying this approach to equally overcome effects of group dynamics in similar courses as (...) well as to bridge the generational gap that normally exists between students and professors. (shrink)

Malgré sa défiance pour la théorie, la recherche scientifique de Goethe n’est pas allée sans un soin tout particulier porté à la méthode qu’elle devait mettre en œuvre. Précisément parce qu’il fallait rendre compte du phénomène dans sa diversité et dans sa totalité, il importait de réfléchir aux moyens qui assureraient la réussite d’une telle démarche. Pour Goethe, il s’agissait de mettre en œuvre un concours harmonieux des différentes facultés de l’esprit humain, seul capable de répondre à la richesse du (...) réel tel qu’il se manifeste à nous, et donc seul capable de fonder adéquatement une démarche expérimentale en science. (shrink)

Objective Apeiron was founded in 1966 and has developed into one of the oldest and most distinguished journals dedicated to the study of ancient philosophy, ancient science, and, in particular, of problems that concern both fields. Apeiron is committed to publishing high-quality research papers in these areas of ancient Greco-Roman intellectual history; it also welcomes submission of articles dealing with the reception of ancient philosophical and scientific ideas in the later western tradition. The journal appears quarterly. Articles are peer-reviewed on (...) a double-blind basis. Topics ancient philosophy ancient science reception of ancient philosophical and scientific ideas in the later western tradition Article formats Original Articles. (shrink)

Regular groups and fields are common generalizations of minimal and quasi-minimal groups and fields, so the conjectures that minimal or quasi-minimal fields are algebraically closed have their common generalization to the conjecture that each regular field is algebraically closed. Standard arguments show that a generically stable regular field is algebraically closed. LetKbe a regular field which is not generically stable and letpbe its global generic type. We observe that ifKhas a finite extensionLof degreen, thenPhas unbounded orbit under the action of (...) the multiplicative group ofL.Known to be true in the minimal context, it remains wide open whether regular, or even quasi-minimal, groups are abelian. We show that if it is not the case, then there is a counter-example with a unique nontrivial conjugacy class, and we notice that a classical group with one nontrivial conjugacy class is not quasi-minimal, because the centralizers of all elements are uncountable. Then, we construct a group of cardinality ω1with only one nontrivial conjugacy class and such that the centralizers of all nontrivial elements are countable. (shrink)

LetMbe a countably infinite ω-categorical structure. Consider Aut(M) as a complete metric space by definingd(g, h) = Ω{2−n:g(xn) ≠h(xn) org−1(xn) ≠h−1(xn)} where {xn:n∈ ω} is an enumeration ofMAn automorphism α ∈ Aut(M) is generic if its conjugacy class is comeagre. J. Truss has shown in [11] that if the set P of all finite partial isomorphisms contains a co-final subset P1closed under conjugacy and having the amalgamation property and the joint embedding property then there is a generic (...) automorphism. In the present paper we give a weaker condition of this kind which is equivalent to the existence of generic automorphisms. Really we give more: a characterization of the existence of generic expansions (defined in an appropriate way) of an ω-categorical structure. We also show that Truss' condition guarantees the existence of a countable structure consisting of automorphisms ofMwhich can be considered as an atomic model of some theory naturally associated toM. We do it in a general context of weak models for second-order quantifiers.The author thanks Ludomir Newelski for pointing out a mistake in the first version of Theorem 1.2 and for interesting discussions. Also, the author is grateful to the referee for very helpful remarks. (shrink)

Let be a countable first order structure and endow the universe of with the discrete topology. Then the automorphism group of becomes a topological group. A tuple of automorphisms is defined to be weakly generic iff its diagonal conjugacy class (in the algebraic sense) is dense (in the topological sense) and the ‐orbit of each is finite. Existence of tuples of weakly generic automorphisms are interesting from the point of view of model theory as well as from the (...) point of view of finite combinatorics.The main results of the present work are as follows. In Theorem 2.6 we characterize the existence of tuples of weakly generic automorphisms with the aid of the profinite topology of free groups. In Corollary 2.12 we will show that if has finite topological rank r (and satisfies a further, mild technical condition) then the existence of a weakly generic tuple in implies the existence of weakly generic tuples in for all natural number. Finally, in Theorem 3.2 we show that if is a countable model of an ℵ0‐categorical, simple theory in which all types over the empty set are stationary and has a pair of weakly generic automorphisms then it has tuples of weakly generic automorphisms of arbitrary finite length.At the technical level we will combine elementary investigations about the profinite topology of free groups with the results of [11] about topological ranks of the automorphism groups of some structures. (shrink)

Let D be a division ring such that the number of conjugacy classes of the multiplicative group D ∗ is equal to the power of D ∗ . Suppose that H is the group GL or PGL, where V is a vector space of infinite dimension ϰ over D . We prove, in particular, that, uniformly in κ and D , the first-order theory of H is mutually syntactically interpretable with the theory of the two-sorted structure 〈κ,D〉 in the (...) second-order logic with quantification over arbitrary relations of power ⩽κ . A certain analogue of this results is proved for the groups ΓL and PΓL . These results imply criteria of elementary equivalence for infinite-dimensional classical groups of types H= ΓL , PΓL , GL, PGL over division rings, and solve, for these groups, a problem posed by U. Felgner. It follows from the criteria that if H≡H then κ 1 and κ 2 are second-order equivalent as sets. (shrink)

We characterize preservation of superstability and ω-stability for finite extensions of abelian groups and reduce the general case to the case of p-groups. In particular we study finite extensions of divisible abelian groups. We prove that superstable abelian-by-finite groups have only finitely many conjugacy classes of Sylow p-subgroups.

We develop a Sylow theory for stable groups satisfying certain additional conditions (2-finiteness, solvability or smallness) and show that their maximal p-subgroups are locally finite and conjugate. Furthermore, we generalize a theorem of Baer-Suzuki on subgroups generated by a conjugacy class of p-elements.

RésuméACarter subgroupis a self-normalizing locally nilpotent subgroup. For studying these subgroups in groups of finite Morley rank, we introduce the new notion of alocally closed subgroup. We show that every solvable group of finite Morley rank has a unique conjugacy class of Carter subgroups.

A Carter subgroup is a self-normalizing locally nilpotent subgroup. For studying these subgroups in groups of finite Morley rank, we introduce the new notion of a locally closed subgroup. We show that every solvable group of finite Morley rank has a unique conjugacy class of Carter subgroups.

Given an admissible indexing φ of the countable atomless Boolean algebra B, an automorphism F of B is said to be recursively presented (relative to φ) if there exists a recursive function $p \in \operatorname{Sym}(\omega)$ such that F ⚬ φ = φ ⚬ p. Our key result on recursiveness: Both the subset of $\operatorname{Aut}(\mathscr{B})$ consisting of all those automorphisms which are recursively presented relative to some indexing, and its complement, the set of all "totally nonrecursive" automorphisms, are uncountable. This arises (...) as a consequence of the following combinatorial investigations: (1) A comparison of the cycle structures of f and f̄, where f is a permutation of some free basis of B and f̄ is the automorphism of B induced by f. (2) An explicit description of the permutations of ω whose conjugacy classes in $\operatorname{Sym}(\omega)$ are (a) uncountable, (b) countably infinite, and (c) finite. (shrink)

Extending techniques of Dowd and those of Poizat, we study computational complexity of in the case when is a generic oracle, where is a positive integer, and denotes the collection of all -query tautologies with respect to an oracle . We introduce the notion of ceiling-generic oracles, as a generalization of Dowd's notion of -generic oracles to arbitrary finitely testable arithmetical predicates. We study how existence of ceiling-generic oracles affects behavior of a generic oracle, by which we show that is (...) not a subset of is comeager in the Cantor space. Moreover, using ceiling-generic oracles, we present an alternative proof of the fact (Dowd) that the class of all -generic oracles has Lebesgue measure zero. (shrink)

This paper investigates indifferent sets for comeager classes in Cantor space focusing of the class of all 1-generic sets and the class of all weakly 1-generic sets. Jockusch and Posner showed that there exist 1-generic sets that have indifferent sets [10]. Figueira, Miller and Nies have studied indifferent sets for randomness and other notions [7]. We show that any comeager class in Cantor space contains a comeager class with a universal indifferent set. A (...) forcing construction is used to show that any 1-generic set, or weakly 1-generic set, has an indifferent set. Such an indifferent set can by computed by any set in GL2 which bounds the (weakly) 1-generic. We show by approximation arguments that some, but not all, ∆0 1-generic sets can compute an indifferent set 2 for themselves. We show that all ∆0 weakly 1-generic sets can compute 2 an indifferent set for themselves. Additional results on indifferent sets, including one of Miller, and two of Fitzgerald, are presented. (shrink)

This paper introduces, as an alternative to the (absolutely) lawless sequences of Kreisel and Troelstra, a notion of choice sequence lawless with respect to a given class D of lawlike sequences. For countable D, the class of D-lawless sequences is comeager in the sense of Baire. If a particular well-ordered class F of sequences, generated by iterating definability over the continuum, is countable then the F-lawless, sequences satisfy the axiom of open data and the continuity principle (...) for functions from lawless to lawlike sequences, but fail to satisfy Troelstra's extension principle. Classical reasoning is used. (shrink)

We study uncertainty relations for a general class of canonically conjugate observables. It is known that such variables can be approached within a limiting procedure of the Pegg–Barnett type. We show that uncertainty relations for conjugate observables in terms of generalized entropies can be obtained on the base of genuine finite-dimensional consideration. Due to the Riesz theorem, there exists an inequality between norm-like functionals of two probability distributions in finite dimensions. Using a limiting procedure of the Pegg–Barnett type, we (...) take the infinite-dimensional limit right for this inequality. Hence, uncertainty relations are derived in terms of generalized entropies. In particular, the case of measurements with a finite precision is addressed. It takes into account that in any experiment an accuracy of performed measurements is always limited. (shrink)

We prove that the conjugacy problem for the automorphism group of the random graph is Borel complete, and discuss the analogous problem for some other countably categorical structures.

We show that for any countable homogeneous ordered graph G, the conjugacy problem for automorphisms of G is Borel complete. In fact we establish that each such G satisfies a strong extension property called ABAP, which implies that the isomorphism relation on substructures of G is Borel reducible to the conjugacy relation on automorphisms of G.

We survey recent developments in the theory of class forcing for- malized in the second-order set-theoretic setting.

First published in 1994. Routledge is an imprint of Taylor & Francis, an informa company.

Argues that a set is the mereological whole of the singleton sets of its members (following Lewis's Parts of Classes), and that the singleton set of X is the state of affairs of X's having some unit-making property.

We study classes of graded structures satisfying the properties of amalgamation, joint embedding and hereditariness. Given appropriate conditions, we can build a graded analogue of the Fraïssé limit. Some examples such as the class of all finite weighted graphs or the class of all finite fuzzy orders (evaluated on a particular countable algebra) will be examined.

This dissertation aims to analyze, clarify, and reconstruct the concept of class consciousness by developing a dialectical account of political agency at work in the concept. I defend a dialectical account of agency, that includes both the way in which individuals come together to form groups, but also the capacity of a collective to transform social conditions. I argue that this account of political agency is necessary in order to understand the possibility of social transformation or change. I trace (...) the development of the relationship between consciousness and agency in the early tradition of Western Marxism, focusing primarily on the account of class consciousness given by Georg Lukács in History and Class Consciousness. Against his account of the world historical agency of a unified proletariat, however, I defend Theodor Adorno’s insistence on nonidentity, and the importance of unreconciled groups in capitalist society. In order to understand these groups, such as the vanguard, party, or proletariat, we must understand the way in which individuals form groups, as well as their inherent collectivity. -/- My account of the political agency at work in the concept of class consciousness is broadly speaking pluralist. I argue that a multiplicity of methodologies is needed in order to arrive at a complete picture of the concept. I defend an account of class consciousness that is neither reductive nor deflationary with respect to other dimensions of social domination. This class forward approach seeks to build intersectional political coalitions in order to undertake revolutionary action. Successful revolutionary social transformation is never guaranteed in advance; however, the concept of class consciousness, reconstructed through the lens of political agency, offers conceptual resources to address the problems of today, for the sake of a better tomorrow. (shrink)

An infinite binary sequence is complex if the Kolmogorov complexity of its initial segments is bounded below by a computable function. We prove that a Π₁⁰ class P contains a complex element if and only if it contains a wtt-cover for the Cantor set. That is, if and only if for every Y⊆ω there is an X in P such that X≥wtt Y. We show that this is also equivalent to the Π₁⁰ class's being large in some sense. (...) We give an example of how this result can be used in the study of scattered linear orders. (shrink)