Fisher [10] and Baur [6] showed independently in the seventies that if T is a complete first-order theory extending the theory of modules, then the class of models of T with pure embeddings is stable. In [25, 2.12], it is asked if the same is true for any abstract elementary class $(K, \leq _p)$ such that K is a class of modules and $\leq _p$ is the pure submodule relation. In this paper we give some instances where this (...) is true:Theorem.Assume R is an associative ring with unity. Let $(K, \leq _p)$ be an AEC such that $K \subseteq R\text {-Mod}$ and K is closed under finite direct sums, then: •If K is closed under pure-injective envelopes, then $\mathbf {K}$ is $\lambda $ -stable for every $\lambda \geq \operatorname {LS}(\mathbf {K})$ such that $\lambda ^{|R| + \aleph _0}= \lambda $.•If K is closed under pure submodules and pure epimorphic images, then $\mathbf {K}$ is $\lambda $ -stable for every $\lambda $ such that $\lambda ^{|R| + \aleph _0}= \lambda $.•Assume R is Von Neumann regular. If $\mathbf {K}$ is closed under submodules and has arbitrarily large models, then $\mathbf {K}$ is $\lambda $ -stable for every $\lambda $ such that $\lambda ^{|R| + \aleph _0}= \lambda $.As an application of these results we give new characterizations of noetherian rings, pure-semisimple rings, Dedekind domains, and fields via superstability. Moreover, we show how these results can be used to show a link between being good in the stability hierarchy and being good in the axiomatizability hierarchy.Another application is the existence of universal models with respect to pure embeddings in several classes of modules. Among them, the class of flat modules and the class of $\mathfrak {s}$ -torsion modules. (shrink)

We characterize rings over which every cotorsion module is pure injective in terms of certain descending chain conditions and the Ziegler spectrum, which renders the classes of von Neumann regular rings and of pure semisimple rings as two possible extremes. As preparation, descriptions of pure projective and Mittag–Leffler preenvelopes with respect to so-called definable subcategories and of pure generation for such are derived, which may be of interest on their own. Infinitary axiomatizations (...) lead to coherence results previously known for the special case of flat modules. Along with pseudoflat modules we introduce quasiflat modules, which arise naturally in the model-theoretic and the category-theoretic contexts. (shrink)

This paper studies various equivalent characterizations of left semisimple rings from the standpoint of reverse mathematics. We first show that \ is equivalent to the statement that any left module over a left semisimple ring is semisimple over \. We then study characterizations of left semisimple rings in terms of projective modules as well as injective modules, and obtain the following results: \ is equivalent to the statement that any left module over a left (...) semisimple ring is projective over \; \ is equivalent to the statement that any left module over a left semisimple ring is injective over \; \ proves the statement that if every cyclic left R-module is projective, then R is a left semisimple ring; \ proves the statement that if every cyclic left R-module is injective, then R is a left semisimple ring. (shrink)

This paper studies the structure of semisimple rings using techniques of reverse mathematics, where a ring is left semisimple if the left regular module is a finite direct sum of simple submodules. The structure theorem of left semisimple rings, also called Wedderburn-Artin Theorem, is a famous theorem in noncommutative algebra, says that a ring is left semisimple if and only if it is isomorphic to a finite direct product of matrix rings over division (...) rings. We provide a proof for the theorem in $$\mathrm RCA_{0}$$, showing the structure theorem for computable semisimple rings. The decomposition of semisimple rings as finite direct products of matrix rings over division rings is unique. Based on an effective proof of the Jordan-Hölder Theorem for modules with composition series, we also provide an effective proof for the uniqueness of the matrix decomposition of semisimple rings in $$\mathrm RCA_{0}$$. (shrink)

This paper was a comment on address at a conference whose proceedings were published by The Personalist (now the Pacific Philosophical Quarterly.) It was pure ephemera and only someone interested in the paper on which it was a comment would find this of interest. I have no copy of it remaining and have, at this distance, no memory of what I might have said.

Schur’s Lemma says that the endomorphism ring of a simple left R-module is a division ring. It plays a fundamental role to prove classical ring structure theorems like the Jacobson Density Theorem and the Wedderburn–Artin Theorem. We first define the endomorphism ring of simple left R-modules by their Π10\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Pi ^{0}_{1}$$\end{document} subsets and show that Schur’s Lemma is provable in RCA0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm RCA_{0}$$\end{document}. A ring (...) R is left primitive if there is a faithful simple left R-module and left semisimple if the left regular module RR\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_{R}R$$\end{document} is semisimple. The Jacobson Density Theorem and the Wedderburn-Artin Theorem characterize left primitive ring and left semisimple ring, respectively. We then study such theorems from the standpoint of reverse mathematics. (shrink)

Extending the language of rings to include predicates for Jacobson radical relations, we show that the theory of regular rings defined by Carson, Lipshitz and Saracino is the model completion of the theory of semisimple rings. Removing the requirement on the Jacobson radical (reduced to {0}), we prove that the theory of rings with no nilpotents does not admit a model companion relative to this augmented language.

We present numerous natural algebraic examples without the so-called Canonical Base Property (CBP). We prove that every commutative unitary ring of finite Morley rank without finite-index proper ideals satisfies the CBP if and only if it is a field, a ring of positive characteristic or a finite direct product of these. In addition, we construct a CM-trivial commutative local ring with a finite residue field without the CBP. Furthermore, we also show that finite-dimensional non-associative algebras over an algebraically closed field (...) of characteristic [Formula: see text] give rise to triangular rings without the CBP. This also applies to Baudisch’s [Formula: see text]-step nilpotent Lie algebras, which yields the existence of a [Formula: see text]-step nilpotent group of finite Morley rank whose theory, in the pure language of groups, is CM-trivial and does not satisfy the CBP. (shrink)

In this paper we present the generalization of neutrosophic rings and neutrosophic fields. We also extend the neutrosophic ideal to neutrosophic biideal and neutrosophic N-ideal. We also find some new type of notions which are related to the strong or pure part of neutrosophy. We have given sufficient amount of examples to illustrate the theory of neutrosophic birings, neutrosophic N-rings with neutrosophic bifields and neutrosophic N-fields and display many properties of them in this paper.

Let l be a commutative field; Bauval [1] showed that the theory of the ring l[X1,...,Xm] is the same as the weak second-order theory of the field l. Now, l[X1,...,Xm] is the ring of the monoid m, so it may be asked what properties of m we can deduce from the theory of l[;m], that is, if l[m] is elementarily equivalent to the ring of monoid k[G], with k, a field and G, a monoid, what do we know not only (...) about the first-order theory of G but also about more properties of G. We prove that in this case G is isomorphic to m.Bauval [1, Theorem V.2.1] proved that if a factorial ring A is elementarily equivalent to l[;X1,...,Xm], then A is isomorphic to F[X1,...,Xm], with F being the field of invertible elements of A.Our result is different from this property because, a priori, the field k is not the field of invertible elements . Furthermore, k[G]; is not always factorial or Neotherian: if G is isomorphic to the cartesian product ∏i<ω, then the number of irreducible elements that divide elements that divide X is infinite, and the ideal generated by the monomials X is not finitely generated.We recall that to be factorial of Neotherian are not elementary properties. (shrink)

We give a definition, in the ring language, of Zp inside Qp and of Fp[[t]] inside Fp), which works uniformly for all p and all finite field extensions of these fields, and in many other Henselian valued fields as well. The formula can be taken existential-universal in the ring language, and in fact existential in a modification of the language of Macintyre. Furthermore, we show the negative result that in the language of rings there does not exist a uniform (...) definition by an existential formula and neither by a universal formula for the valuation rings of all the finite extensions of a given Henselian valued field. We also show that there is no existential formula of the ring language defining Zp inside Qp uniformly for all p. For any fixed finite extension of Qp, we give an existential formula and a universal formula in the ring language which define the valuation ring. (shrink)

We show that certain classes of modules have universal models with respect to pure embeddings: Let R be a ring, T a first‐order theory with an infinite model extending the theory of R‐modules and (where ⩽pp stands for “pure submodule”). Assume has the joint embedding and amalgamation properties. If or, then has a universal model of cardinality λ. As a special case, we get a recent result of Shelah [28, 1.2] concerning the existence of universal reduced torsion‐free abelian (...) groups with respect to pure embeddings.We begin the study of limit models for classes of R‐modules with joint embedding and amalgamation. We show that limit models with chains of long cofinality are pure‐injective and we characterize limit models with chains of countable cofinality. This can be used to answer [18, Question 4.25].As this paper is aimed at model theorists and algebraists an effort was made to provide the background for both. (shrink)

This paper provides the first examples of rings of algebraic numbers containing the rings of algebraic integers of the infinite algebraic extensions of where Hilbert's Tenth Problem is undecidable.

The fields K) of generalized power series with coefficients in a field K and exponents in an additive abelian ordered group G play an important role in the study of real closed fields. The subrings K) consisting of series with non-positive exponents find applications in the study of models of weak axioms for arithmetic. Berarducci showed that the ideal JK) generated by the monomials with negative exponents is prime when is the additive group of the reals, and asked whether the (...) same holds for any G. We prove that this is the case and that in the quotient ring K)/J, each element admits at least one factorization into irreducibles. (shrink)

We continue the study of a theory which is a valued analogue of the theory of regular rings studied by Carson, Lipshitz and Saracino, characterize it as the model companion of the theory of Prüfer rings, and prove its decidability. We then link it to the theory of p.p. rings developed by Weispfenning and show that it admits quantifier elimination in a related language.

We use the Drozd-Warfield structure theorem for finitely presented modules over a serial ring to investigate the model theory of modules over a serial ring, in particular, to give a simple description of pp-formulas and to classify the pure-injective indecomposable modules. We also study the question of whether every pure-injective indecomposable module over a valuation ring is the hull of a uniserial module.

In important respects measurement practices underlay both the Second Scientific Revolution and the Second Industrial Revolution. Such practices, using increasingly accurate and precise instruments, both turned laboratories into factories for the production of exact measurement and also made factories the sites of laboratory-type and laboratory-quality measurement. Those who had learnt the protocols of precise, instrumentational measurement in university science and engineering classrooms, used those instruments and their skills to monitor and control industrial production, exchange technical data within and among firms (...) and formulate and implement technical standardization in industry. That these instruments measured not natural phenomena but technological ones made them no different in kind from what are more conventionally regarded as scientific instruments. Some indeed were simply instruments developed for scientific investigation and adapted for industrial use while others were created specifically for particular industrial applications. But more than the purely technical was going on in the use of those instruments. In addition to their function of producing knowledge they were also, in industrial production, instruments of hegemony – hegemony which, as Gramsci reminds us, begins in the factory. Among the lesser known of these devices is the freeness tester, used in production to control the manufacture of pulp and also in industrial research laboratories for the investigation of the pulping process. The Canadian Standard Freeness Tester (CSFT), developed at a Canadian government research facility on the campus of McGill University in the 1920s, quickly became a standard instrument in the pulp mills of North America and gained wide acceptance in other countries; it remains in use to this day. An understanding of its creation and function can provide a useful case study of the general observations discussed above. (shrink)

continent. 1.1 (2011): 60-67. At the beginning of Martin Heidegger’s lecture “Time and Being,” presented to the University of Freiburg in 1962, he cautions against, it would seem, the requirement that philosophy make sense, or be necessarily responsible (Stambaugh, 1972). At that time Heidegger's project focused on thinking as thinking and in order to elucidate his ideas he drew comparisons between his project and two paintings by Paul Klee as well with a poem by Georg Trakl. In front of Klee's (...) Saints from the Window and Death of Fire —though we wouldn’t absolutely understand what we were seeing—he writes, “we should want to stand…a long while.” In a similar manner, of Trakl’s poem “Septet of Death”—although it is likely we are unsure in what we hear—Heidegger states that, “we should want to hear…[it] often.” Heidegger further states that in appreciating these, “we “should abandon any claim that [they] be immediately intelligible” (1). So also we must we approach, Heidegger continues, the realm of theoretical physics, in which the difficult work of Werner Heisenberg, be listened to “without protest” and without “any claim that he be immediately understood.” These works, like his own project, merit the time they take to be originally (mis)understood. But this is not necessarily true for philosophy, Heidegger advises, because, “That thinking is supposed to offer ‘worldly wisdom’ and perhaps even a ‘way to a blessed life’” (1). Philosophy is in the unique position of being both abstract (what do we talk about when we talk?) and at the same moment, useful. There are demands that it make sense, that it be, grounded, immediate, and most importantly, rational. Heidegger draws these comparisons between the works of Klee and Trakl and Heisenberg not to claim that philosophy is totally irresponsible. He does not claim that the poet, the painter, nor the physicist have acted irresponsibly. Rather, he would say, they are rising to the highest levels of intelligibility, though it is perhaps an intelligibility that is commonly unavailable to us. In Trakl’s case, as we shall see, mastery is the end result of difficult words. Instead, Heidegger seems be making pleas: for a period of uninterrupted unintelligibility (pure unintelligibility); and that there is a time (that time is now) when, “thinking is…placed in a position which demands of it reflections that are far removed from any useful, practical wisdom” (1-2). Heidegger argues that philosophy requires a period of time in which, instead of focusing on the practical—or even on the worldly—the discipline draw its “determination” instead from the place of painting and poetry and physics. In doing so, “we should have to abandon any claims to immediate intelligibility” (2). But Heidegger doesn’t offer this as a way out. We still have to turn up, we “still have to listen, because we must think what is inevitable, but preliminary” (2). The point for Heidegger, is not to listen to a series of propositions, but instead to “follow the movement of showing” (2). I. … Maybe we're here only to say: house, bridge, well, gate, jug, olive tree, window— at most: pillar, tower … but to say them, remember, oh, to say them in a way that the things themselves never dreamed of existing so intensely.… Rainer Maria Rilke, “The Ninth Elegy” There is little more fundamental, preliminary, in the world than language. We use language, in the form of speech, constantly, whether we are saying anything or not. “Man speaks,” Heidegger writes, and goes on to describe in his essay “Language” (2001) the constant speaking that we do. “We are always speaking, even when we do not utter a single word aloud, but merely listen or read, and even when we are not particularly speaking or listening but are attending to some work or taking a rest” (187). Speaking is expression, an utterance of something internal. It is a recognition of a world. It is a way of communicating thought and it is an activity that we all do, inevitably. Speaking separates the human from the animal world, and despite advances in primatology that seek to give ‘voice’ to primates and other non-human animals, it can safely be said that our form of communication—what we call speech and know as language—is the most advanced, the most complicated. We use it to present and represent the world around us; through actual utterances (vocalization) or through the written word or through ‘unvoiced thoughts’ and dreams. We use language, but more specifically speech—naming—to transmit moods, thoughts, desires, aversions, and feelings. These expressions, mere utterances, nearly always find a source in words, whether spoken or not. Heidegger writes that this common view of language means “that only speech enables man to be the living being he is as man. It is as the one who speaks that man is—man” (187). Speaking then—utterance—surrounds us constantly, whether in the form of careful thought—in the form of an academic paper, say—or in the half mutterings and forgotten thoughts of a nearly remembered dream. Like scaffolding, the apparatus of speech sustains and explains the world, making, in a sense, the world rational, making it apparent. When we speak, we describe, and in doing so, name the world. We use words, through this process of naming, to interpret and sustain the world we see, and the world we imagine. Like Rilke’s naming of jug, and bridge, and window, and stream, we describe—and inscribe upon—the world through an activity of naming. Are we here, perhaps, to name? Is it possible not to name? Is it possible to regard and to view and to look around without naming what we see? Is it possible to feel—to experience—world without giving utterance to that feeling, that process? Sadness, grief, joy, ecstasy, hunger, thirst. Desk, light, room, pen, book, world. White, black, tomorrow, today. Each of these words is a name given to a thing I see in front of me, or a concept that I imagine (in the case of tomorrow or world). What arises in my mind has already existed. If I imagine it, it is named. The word for ‘tomorrow’ and ‘desk’ and ‘light’ precedes me, and precedes my concept of it. The idea of it is already pre-informed, and I must, in a certain sense, bend my ideas to it. When I imagine a table, I imagine my own table (or I imagine an idea of table) but that imagining must follow certain general rules; while, perhaps, it might not always require four legs and a horizontal surface, it must, at least not be, say, a pool of water, or a pile of excrement. It must have some tableness to it to be a table. It must, with Heidegger, table. Otherwise, speech is reduced to gibberish. For Heidegger however, the discussion of language points to something deeper than its “scientific and analytic” study as a communicative device. Indeed, Heidegger seeks to understand language not in reference to man or woman, not as an utterance of humanity, but in reference to itself. In doing so he abandons the conversation—that is, he casts away the traditional arguments surrounding philosophy of language; that it is a means of expression; that it is a human activity; and that it is somehow a representation of something that is—in order to seek to understand language as language, on its own terms. Heidegger is not a philosopher of language, but a philosopher of world, of being. Despite these “correct ideas” holding sway “over the whole field of the varied scientific perspectives on language…they ignore completely the oldest natural cast of language” (191). What is this “oldest natural cast of language? It is the act of language itself. Language is language and language speaks. “Most often,” Heidegger writes, “and too often, we encounter what is spoken only as the residue of a speaking long past” (195). Speech, as we normally encounter it, is like Echo herself calling out to Narcissus, doomed to repeat what has already been said, a mere remnant of what was once language, a trace left behind in the gathering silence of becoming. In both the essay “Language” and in his three lecture course “The Nature of Language” (1982), Heidegger attempts to unpack the seeming tautology of language as language. In each, he focuses on poetry as a way out, or into, a true discussion of the oldest natural cast of language. Poetry is pure speech. In poetry, language is brought to language and language speaks ( Die Sprach spricht ). In the act of poetry, the act of pure speech, the poet names (on the surface not different from how I name this table, this computer) but in the poet naming, the naming does not “hand out titles,” “apply terms,” but rather the naming is a call, a calling forth of entities that bring them into their own, allow them to take their place purely, without compromise. This calling, Heidegger (2001) states, “here calls into a nearness. But even so the call does not wrest what it calls away from the remoteness, in which it is kept by the calling there. The calling calls into itself and therefor always here and there—here into presence, there into absence” (196). II. Window with falling snow is arrayed, Long tolls the vesper bell, The house is provided well, The table is for many laid. Wandering ones, more than a few, Come to the door on darksome courses. Golden blooms the tree of graces Drawing up the earth’s cool dew. Wanderer quietly steps within; Pain has turned the threshold to stone. There lie, in limpid brightness shown, Upon the table bread and wine. Georg Trakl “A Winter Evening” Heidegger is often given short shrift as an abysmally difficult writer, as one that makes no sense and is needlessly difficult. In doing this though, we forget sometimes his eloquence, his simple beauty in writing. Of the above opening stanza, “Window with falling snow is arrayed/ Long tolls the vesper bell.” he writes (2001), This speaking names the snow that soundlessly strikes the window late in the waning day, while the vesper bell rings. In such a snowfall, everything lasts longer. Therefore the vesper bell, which daily rings for a strictly fixed time, tolls long. The speaking names the winter evening time (197). The speaking names the winter evening time. It is almost impossible to comment on that one line by Heidegger. It is as though it must exist on its own completely, without elucidation—as though in front of it we must stand as we do in front of a painting by Klee, that is, we must abandon any claim . Silent and devoted. The speaking of the poem here is not clearly different from common speech ( rede ) yet there is, via Heidegger, an invitation to experience that auracular quality of light and stillness that a gentle, dusk tinged snowfall gives; words evoking a quality so clear, so poignant that, in a sense, Heidegger’s work, at this moment, has been done. But what does this naming accomplish? What does the call call? Remember, it is not the poet that calls, but the naming which calls. The poet has only brought the words forward; it is now the words— snow, vesper bell, window— that take new life in the pure language of the poem. Entities are called forth into presence, like the speaking that names the winter evening time. Not to be present amongst us now, however; naming ‘table’ in the poem does not place it in front of us in this room. Rather, the naming places entities into a gathering which is also a sheltering. The naming brings them to be. In an act of appropriation, things come to be purely as their own, unimpeded by a predetermined expectation. They are called to themselves into an arrival. In Being and Time (1962), Heidegger famously describes the movement between present-at-hand and ready-to-hand in his analysis of the hammer, and of equipment in general. This analysis is already known, if not always clear, to most readers of Heidegger. Briefly, a hammer is ordinarily zuhanden or ready-to-hand; it is part of the background of the world, equipment used and never thought about, like this desk, this sheet of paper, this room. Our interaction with it is temporary and it is historically different for each entity and each relation. We need a hammer, we use a hammer. If all goes according to plan, the hammer remains ready-to-hand; it remains, in a sense, undisclosed and certainly unobtrusive. Our world is undisturbed by the hammer. Only when the hammer or the car or the computer is broken (or sometimes unused or unrecognized or missing) does it intrude into our world, become conspicuous as an object present-at-hand, or vorhanden . In this case, we reach for the hammer, it is broken and we suddenly notice it’s being, broken though it is. The thing which was always ready to hand—handy—is suddenly abstract, something to be examined, if only in its absence or disfunction. This can be exhibited for all entities, and it is important to note that in this analysis the zuhanden / vorhanden split is not restricted to a specific form of constructed material; zuhanden does not refer to the car, and vorhanden the sunset. No entity is ever exclusively ready-to-hand or present-at-hand; they are instead, interpenetrated with each others mode of being, one informing the other in a way that both brings things forth into the world—discloses is the word Heidegger chooses—and at the same time conceals them. As one mode is coming to be so another mode is withdrawing. This flux and movement between modes is precisely what brings the world forward, and what makes it manifest. It exists beyond where we tread and before man took dubious control of the world. We go to find a book or turn on the computer and it is missing or broken and we become aware of the object, as though for the first time. We walk to the water to glimpse the sunset and miss it, or it is less than stellar; in the sunset’s grayness, we become aware of it’s being sunset. The thing is disclosed in its withdrawal. Echoing Heraclitus, we can say that as something is coming to be, it is already becoming something other. Of similar importance to the fact that things are never all of one, or all of the other, they are also never alone. The hammer is never a single object, but is in relation always to the whole. Heidegger (1962) states, Equipment—in accordance with its equipmentality—always is in terms of its belonging to other equipment: ink-stand, pen, ink, paper, blotting pad, table, lamp, furniture, windows, doors, room. These ‘Things’ never show themselves proximally as they are for themselves…What we encounter as closest to us…is the room; and we encounter it not as something ‘between four walls’ in a geometrical, spatial sense, but as equipment for residing…it is in this that any ‘individual’ item of equipment shows itself. Before its does so, a totality of equipment has already been discovered (97). Equipment resides—dwells—in its relations, in its proximal being to other beings. Within the structure of totality, a series of relations is always occurring. The hammer is on the workbench in the carpenter’s hand in the workshop in the village under the sky and under the sun. It doesn’t stop there. Equipment surrounds us and the focus is not on what it does, or what one does with it—the carpenter with the hammer, the writer with laptop—but with the fact that it is. Equipment occurs in relation and is always occurring around us overhead, underfoot, by the stream and in the city. There is a constant exchange of relations happening, and as this occurs, so the world occurs, so the world both discloses and withdraws, into and out of itself. In a very real sense, language is also equipment. It is the thing that we use most often without thought, it is ready-to-hand (except when it’s not.) As we re- cognize the world around us, as we offer names for things and make lists, we are using language much like we might use a hammer, that is, bluntly. Most of the time it is invisible and we draw on it without wondering how we are going to say something. When language does intrude, it does so in an awkward moment, that moment when we can’t remember the right word, when we forget a phrase. At that second, it “speaks itself as language,” it reveals itself as malfunctioning equipment, and we “undergo” an experience with language, in Heidegger’s famous formulation. Language is not a tool anymore that we use to bludgeon an object, but something instead that we submit to, that we experience. In “The Nature of Language,” Heidegger (1982) writes, But when does language speak to us as language? Curiously enough, when we cannot find the right word for something that concerns us, carries us away, oppresses or encourages us. Then we leave unspoken what we have in mind and, without rightly giving it a thought, undergo moments in which language itself has distantly and fleetingly touched us with its essential being (59). The poet’s words become themselves, become appropriate, only when they no longer function in the prosaic world; they instead intrude as they come to be. Language itself brings itself to language. Names, like the entities they indicate, are always becoming something else. As noted above, language, through the poet, has brought forth entities from words previously “known.” I thought that I knew snow, but through Trakl’s re- presentation of the word, language calls forth a new image of snow, indeed calls forth snow itself. The vesper bell tolls longer, the table is for many laid. In bringing forth things , language has brought the world to presence. In everyday naming, word occludes world, preventing, in its everydayness, its coming forth, its disclosing. But what is this world that word has been brought forth into? In the same way that language speaks, world worlds. World, left alone, un-interfered with, comes into itself. It worlds. Again, this sounds like a tautology, but it is essential to Heidegger’s thought (and in my mind is more of a “god killer” than Nietzsche.) One of the most overlooked (and under-appreciated) aspects of Heidegger is his later examination and enthusiasm for the “fourfold,” or the system through which things come to be, through which things thing in a world worlding. The fourfold is the interaction of earth and sky, mortals and gods. Things come to be in the interstices and gathering of the fourfold. The fourfold provides both a place of being, and a sheltering, a place to dwell. Heidegger writes that “the things that were named, thus called, gather to themselves sky and earth, mortals and divinities. The four are united primally in being toward one another, a fourfold.” The poet has called, through the act of pure naming, things to come forth. In the purity of the fourfold—that is, when that is all that there is, when there are no other distractions, definitions, things—entities themselves can come to be. It is important to note that Heidegger is not saying that there are four formal things in the world, autonomous entities unto themselves. He is not evoking a pre-Socratic formula as to what makes up the world; instead, the four mirror each other constantly. (Heidegger calls this the ‘mirror-play.’) They interpenetrate in the same way that the modes of being of things interpenetrate themselves. There is no discrete exclusivity in being or the fourfold. What makes up things is not a precise recipe of the four main components; what makes up things is the action of the fourfold coming together, the movement of the fourfold which is a becoming. Heidegger (2001) writes that “this gathering, assembling, letting stay is the thinging of things.” And he later adds that “thinging, things are things. Thinging, they gesture—gestate—world” (197). Language brings the world to be. It works not again as a recipe added to things, but instead it is a bridge, or more precisely, a relation. Language relates world to thing, brings world to thing. In a sense, it does not say anything; rather it allows, or calls in its movement. Heidegger (2001) writes that, The intimacy of world and thing is not a fusion. Intimacy obtains only where the intimate—world and thing—divides itself cleanly and remains separated. In the midst of the two, in the between of world and thing, in their inter, division prevails: a dif-ference (199). It is in this inter that language prevails. Language is difference, it is the differential aspect between world and thing that brings world to thing. In the final stanza of Trakl’s poem “The Winter Evening,” Trakl evokes this difference in the second line when he writes, “Pain has turned the threshold to stone.” Christopher Fynsk, in his essay “Noise at the Threshold,” draws attention to this point when he writes “it is the figure of the threshold that is language itself, inasmuch as language is defined as the articulation of difference by which difference comes about” (25). Language, as used in the pure language of the poem, draws together world and thing, bridging relation between entity and world. The calling of language calls world to thing, world to being. Heidegger (2001) describes this difference as unique; “of itself, it holds apart the middle in and through which world and things are at one with each other” (200). III. Neither reading nor writing, nor speaking—and yet it is by those paths that we escape what has been said already, and knowledge, and reciprocity, and enter the unknown space, the space of distress where what is given is perhaps not received by anyone (99). Maurice Blanchot The Writing of Disaster So far, we have allowed Heidegger to put forward what language does, how it functions as a relation and how it operates as a threshold, as a bridge. What interests me is what happens beyond language, beyond the relation. What happens to the thing without the naming, without the poet, or even without the everyday chatter—Fynsk calls this ‘noise’—intruding on being? If language allows things to become by bringing thing to world, what happens when we remove this bringing, this threshold turned to pain? In “The Nature of Language,” Heidegger examines the work of the poet Stefan George, specifically “The Word”: Wonder or dream from distant land I carried to my county’s strand And waited till the twilight norn Had found the name within her bourn— Then I could grasp it close and strong It blooms and shines now the front along… Once I returned from happy sail, I had a prize so rich and frail, She sought for long and tidings told: “No like of these depths unfold.” And straight it vanished from my hand, The treasure never graced my land… So I renounced and sadly see: Where word breaks off no thing may be. That final line, “Where word breaks off no thing may be” is evoked on nearly every page of Heidegger’s essay. It is the line to which he returns over and over and bears repeating. Where word breaks off no thing may be. Where naming ends, no thing. We can interpret this in two ways (at least.) Where word—naming—breaks off, then there is nothing . Or, as I choose to read it, where word breaks off no thing may be. In this I see a hint forward, a marker left behind by Heidegger. What could this look like? What does no thing look like? Like a zen koan ( there is no mirror ) it is as thrilling and horrifying as contemplating what preceded the Big Bang. Because language as naming wasn’t always here; we weren’t always here. One or maybe two aspects of the fourfold (depending on your view of gods) were not always here, and there is no guarantee that we will always be around. What then? Heidegger (1982) describes the landscape that the poet finds, “It names the realm into which the renunciation must enter: it names the call to enter into that relation between thing and word which has now been experienced” (65). The poet, in renouncing, allows for the “may be” of “where word breaks off no thing may be.” This “may be” becomes “a kind of imperative, a command which the poet follows, to keep it from then on.” No thing is lacking. Where word breaks off, there may be, a totality, a completion. If we place the emphasis on may be , we make it affirmative, make it positive. One allows it. No thing is where the word, that is the name, is lacking. If we remove then (if we can remove) the word, the name, than that is where no thing is, that is where no thing may blossom, enrich, belong, become. What is no thing? Heidegger writes that “thing is anything that in any way is.” And just after this he writes that the “world alone gives being to the thing.” But what happens if there is no word? Word, in this formulation can be seen as an enframing, a challenging of language. By naming, by drawing a perimeter around an object, we hold it, by its definition (that is a brick) to an ordered future. If we borrow from Heidegger’s essay “The Question Concerning Technology” (1993) the idea of this standing-reserve of an ordered future, we see that “everywhere everything is ordered to stand by, to be immediately on hand, indeed to stand there just so that it may be on call for a further ordering” (322). What happens if there is no naming of the thing? Silence perhaps. Stillness. We can name—and do name—that which we know. We equate knowledge with knowing the name of something. A brick is a brick, a hammer is a hammer, the universe is the universe. By naming a thing, we create, and draw its parameters, the parameters of the thing, not as thing thinging in the fourfold, but as blunt object apparent. In the four dimensions relatively available to us, we observe (and name) that the brick takes up possibly six by four by two inches and is, in the sense that it currently occupies this time slot. It fulfills its destiny, its being, its brickness, it bricks . But what happens when we remove the name for this brick. We no longer know what to call this no-thing (if indeed we can even arrive at the point of uncalled calling.) In fact the it (this brick) is no longer a thing in the sense that by not naming—by removing the name—it still occupies the same dimension but is indiscernible from the world. It simply is , un-reliant, un- needed by me. By removing the subject (me) from it (the brick) do I not then also remove the object—or at least the duality objectifying it? Why is this important? Why does this matter? I have not really removed anything. I have not changed any thing , per se . The brick still occupies the same space in geographic and temporal dimensions. I have literally not even touched the brick sitting on my desk. But what I have done is removed the name, removed the word (the bridge, according to Heidegger) and in this (again, if this is even possible) there is something vertiginously liberating, not only for me (and my way of thinking) but also for the brick itself. Like the poet who calls the thing forward, by refusing to name, by avoiding any thing that demands me to name it, I release the thing into the fourfold. I am no longer challenging the thing to be there for me ; I do not en frame it through language. Rather I, in an act of extreme responsibility, am refusing the challenge. By refusing the name (refusing to name) one allows, (or no one allows no thing) the brick to be all things , to manifest its manifold being, to incorporate all things into its thinging . It becomes, quite literally, every thing . Because, in its infinite manifestness, it incorporates everything; the mud that gave it its current being, the water that formed the mud, the sun, the stars, the universe and it also allows it to become mud again, to become landfill, to become again, water and sun and stars and universe in an endless, infinite cycle of coming to be some thing (else). Perhaps this is what Heidegger is suggesting when he talks about the stillness at the end of his essay, “Language” (2001): The dif-ference stills particularly in two ways: it stills the things in thinging and the world in worlding. Thus stilled, thing and world never escape from the dif-ference. Rather, they rescue it in the stilling, where the dif-ference is itself the stillness (206). It is in this stillness that I can imagine a gellasenheit (here I mean both “releasement in the Heideggarean sense, as well as Meister Eckhart’s use of the term meaning “letting the world go and giving oneself to God”) of thing and world, a releasing into the stillness and silence of no thing beyond where word breaks off. It is here where I may no longer be, and yet no thing is, but may be. (shrink)

Let [Formula: see text] be an expansion of either an ordered field [Formula: see text], or a valued field [Formula: see text]. Given a definable set [Formula: see text] let [Formula: see text] be the ring of continuous definable functions from [Formula: see text] to [Formula: see text]. Under very mild assumptions on the geometry of [Formula: see text] and on the structure [Formula: see text], in particular when [Formula: see text] is [Formula: see text]-minimal or [Formula: see text]-minimal, or (...) an expansion of a local field, we prove that the ring of integers [Formula: see text] is interpretable in [Formula: see text]. If [Formula: see text] is [Formula: see text]-minimal and [Formula: see text] is definably connected of pure dimension [Formula: see text], then [Formula: see text] defines the subring [Formula: see text]. If [Formula: see text] is [Formula: see text]-minimal and [Formula: see text] has no isolated points, then there is a discrete ring [Formula: see text] contained in [Formula: see text] and naturally isomorphic to [Formula: see text], such that the ring of functions [Formula: see text] which take values in [Formula: see text] is definable in [Formula: see text]. (shrink)

Suppose that T is an equational theory of groups or of rings. If T is finitely axiomatizable, then there is a least number μ so that T can be axiomatized by μ equations. This μ can depend on the operation symbols that occur in T. In the 1960s, Tarski and Green completely determined the values of μ for arbitrary equational theories of groups and of rings. While Tarski and Green announced the results of their collaboration in 1970, the (...) only fuller publication of their work occurred as part of a seminar led by Tarski at Berkeley during the 1968–69 academic year. The present paper gives a full account of their findings and their proofs. (shrink)

In this essay, I compare and contrast how Boethius, the author of Beowulf, J. R. R. Tolkien, and C. S. Lewis found ways to integrate their Christian theological and philosophical beliefs into a work that is set in a time and place that possesses the general revelation of creation, conscience, reason, and desire, but lacks the special revelation of Christ and the Bible. I begin by using Lewis’s own analysis of the Consolation in his Discarded Image to discuss what it (...) means for a Christian author to write in a pre-Christian mode. I find a model for such writing in Ecclesiastes, and discuss how Boethius, while confining himself to the pagan wisdom of Greece and Rome, points the way from philosophical consolation to theological transformation. I then use Tolkien’s ‘Beowulf: The Monsters and the Critics’ to unpack the distinction between the author’s Christian faith and the purely pagan consolation he offers to his characters, and locate that dynamic in the epic itself. Next, I explore how Tolkien, in imitation of Beowulf, balances a deep sense of loss and fatalism with an intimation of a higher providence guiding all. Finally, I show how Lewis, in imitation of Boethius, finds in the pagan world of his novel seeds of a greater revelation to come. (shrink)

On the basis of the Klingler–Levy classification of finitely generated modules over commutative noetherian rings we approach the old problem of classifying finite commutative rings R with a decidable theory of modules. We prove that if R is wild, then the theory of all R-modules is undecidable, and verify decidability of this theory for some classes of tame finite commutative rings.

The elementary theories of polynomial rings over finite fields with the coprimeness predicate and two kinds of “successor” functions are studied. It is proved that equality is definable in these languages. This gives an affirmative answer to the polynomial analogue of the Woods–Erdös conjecture. It is also proved that these theories are undecidable.

We present some results concerning elimination of quantifiers and elementary equivalence for Boolean products of real closed valuation rings and fields. We also study rings of continuous functions and rings of definable functions over real closed valuation rings under this point of view.

We consider the problem of constructing first-order definitions in the language of rings of holomorphy rings of one-variable function fields of characteristic 0 in their integral closures in finite extensions of their fraction fields and in bigger holomorphy subrings of their fraction fields. This line of questions is motivated by similar existential definability results over global fields and related questions of Diophantine decidability.

We prove that every ω-categorical, generically stable group is nilpotent-by-finite and that every ω-categorical, generically stable ring is nilpotent-by-finite.

Let G be a finite group, T denote the theory of Z[G]-lattices . It is shown that T is undecidable when there are a prime p and a p-subgroup S of G such that S is cyclic of order p4, or p is odd and S is non-cyclic of order p2, or p = 2 and S is a non-cyclic abelian group of order 8 . More precisely, first we prove that T is undecidable because it interprets the word problem (...) for finite groups; then we lift undecidability from T to T. (shrink)

In this paper we develop a general representation theory for MV-algebras. We furnish the appropriate categorical background to study this problem. Our guide line is the theory of classifying topoi of coherent extensions of universal algebra theories. Our main result corresponds, in the case of MV-algebras and MV-chains, to the representation of commutative rings with unit as rings of global sections of sheaves of local rings. We prove that any MV-algebra is isomorphic to the MV-algebra of all (...) global sections of a sheaf of MV-chains on a compact topological space. This result is intimately related to McNaughton’s theorem, and we explain why our representation theorem can be viewed as a vast generalization of McNaughton’s theorem. In spite of the language used in this abstract, we have written this paper in the hope that it can be read by experts in MV-algebras but not in sheaf theory, and conversely. (shrink)