We consider R-torsionfree modules over group rings RG, where R is a Dedekind domain and G is a finite group. In the first part of the paper [4] we compared the theory T of all R-torsionfree RG-modules and the theory T0 of RG-lattices , and we realized that they are almost always different. Now we compare their behaviour with respect to decidability, when RG-lattices are of finite, or wild representation type.

The study of pairs of modules (over a Dedekind domain) arises from two different perspectives, as a starting step in the analysis of tuples of submodules of a given module, or also as a particular case in the analysis of Abelian structures made by two modules and a morphism between them. We discuss how these two perspectives converge to pairs of modules, and we follow the latter one to obtain an alternative approach to the classification of pairs of torsionfree objects. (...) Then we restrict our attention to pairs of free modules. Our main results are that the theory of pairs of free Abelian groups is co-recursively enumerable, and that a few remarkable extensions of this theory are decidable. (shrink)

Wilfred Sieg and Saverio Cittadini. Normal Natural Deduction Proof (In Non-Classical Logics.

We consider the problem of finding, in the ambit of modal logic, a minimal characterization for finite Kripke frames, i.e., a formula which, given a frame, axiomatizes its theory employing the lowest possible number of variables and implies the other axiomatizations. We show that every finite transitive frame admits a minimal characterization over K4, and that this result can not be extended to K.

We define the concepts of minimal p-morphic image and basic p-morphism for transitive Kripke frames. These concepts are used to determine effectively the least number of variables necessary to axiomatize a tabular extension of K4, and to describe the covers and co-covers of such a logic in the lattice of the extensions of K4.

The semantics of e-models for tense logics with binary operators for `until' and `since' (US-logics) was introduced by Bellissima and Bucalo in 1995. In this paper we show the adequacy of these semantics by proving a general Henkin-style completeness theorem. Moreover, we show that for these semantics there holds a Stone-like duality theorem with the algebraic structures that naturally arise from US-logics.

In this paper we show the adequacy of tense logic with unary operators for dealing with finite trees. We prove that models on finite trees can be characterized by tense formulas, and describe an effective method to find an axiomatization of the theory of a given finite tree in tense logic. The strength of the characterization is shown by proving that adding the binary operators "Until" and "Since" to the language does not result in a better description than that given (...) by unary tense logic; although the greater expressive power of "Until" and "Since" can be exploited by using the semantics of e-frames instead of traditional Kripke semantics. (shrink)

The concept of cell, more than any other biological concept, has been modelled on three powerful metaphors: in a morphological perspective, the cell has been defined Baustein, the brick or elementary unit of the body; from the physiological point of view, it has been associated to a chemical laboratory and finally, in a systemic view, it has been compared to the citizen of the cellular state. The pathologist Rudolf Virchow and the zoologist Ernst Haeckel showed the philosophical and aesthetic potential (...) of the latter metaphor, opening two different perspectives on a crucial problem in the science of living: the problem of the definition of biological individual. (shrink)

A significant proportion of conservationists' work is directed towards efforts to save disappearing species. This relies upon the belief that species extinction is undesirable. When justifications are offered for this belief, they very often rest upon the assumption that extinction brought about by humans is different in kind from other forms of extinction. This paper examines this assumption and reveals that there is indeed good reason to suppose current anthropogenic extinctions to be different in kind from extinctions brought about at (...) other times or by other factors. Having considered – and rejected – quantity and rate of extinction as useful distinguishing factors, four alternative arguments are offered, each identifying a way in which anthropogenic extinction is significantly different from other forms of extinction, even mass extinction: (1) Humans are a different kind of natural cause from other causes of extinction; (2) Extinctions brought about by humans are uniquely persistent; (3) Anthropogenic extinctions are effectively random whereas past mass extinctions are rule-bound; (4) The impact of the current anthropogenic extinction event differs from the impact of other extinction events of the past, such that future recovery may not follow past patterns. Together, these four arguments suggest that the present-day extinction event brought about by humans may be unprecedented and that we cannot clearly extrapolate from past to present recovery from extinctions. Although insufficient as justification for the claim that present-day extinctions are undesirable, the arguments provide some ammunition for conservationists' conviction that species extinction – in which humans play an accelerating role – ought to be prevented. (shrink)

This Is A New Release Of The Original 1922 Edition.

A mathematical model for Vibrio Cholerae (V. Cholerae) in a closed environment is considered, with the aim of investigating the impact of climatic factors which exerts a direct influence on the bacterial metabolism and on the bacterial reservoir capacity. We first propose a V. Cholerae mathematical model in a closed environment. A sensitivity analysis using the eFast method was performed to show the most important parameters of the model. After, we extend this V. cholerae model by taking account climatic factors (...) that influence the bacterial reservoir capacity. We present the theoretical analysis of the model. More precisely, we compute equilibria and study their stabilities. The stability of equilibria was investigated using the theory of periodic cooperative systems with a concave nonlinearity. Theoretical results are supported by numerical simulations which further suggest the necessity to implement sanitation campaigns of aquatic environments by using suitable products against the bacteria during the periods of growth of aquatic reservoirs. (shrink)

In the case of magnetic resonance imaging (MRI) imaging, image processing is crucial. In the medical industry, MRI images are commonly used to analyze and diagnose tumor growth in the body. A number of successful brain tumor identification and classification procedures have been developed by various experts. Existing approaches face a number of obstacles, including detection time, accuracy, and tumor size. Early detection of brain tumors improves options for treatment and patient survival rates. Manually segmenting brain tumors from a significant (...) number of MRI data for brain tumor diagnosis is a tough and time-consuming task. Automatic image segmentation of brain tumors is required. The objective of this study is to evaluate the degree of accuracy and simplify the medical picture segmentation procedure used to identify the type of brain tumor from MRI results. Additionally, this work suggests a novel method for identifying brain malignancies utilizing the Bagging Ensemble with K-Nearest Neighbor (BKNN) in order to raise the KNN’s accuracy and quality rate. For image segmentation, a U-Net architecture is utilized first, followed by a bagging-based k-NN prediction algorithm for classification. The goal of employing U-Net is to improve the accuracy and uniformity of parameter distribution in the layers. Each decision tree is fitted on a little different training dataset during classification, and the bagged decision trees are effective since each tree has minor differences and generates slightly different skilled predictions. The overall classification accuracy was up to 97.7 percent, confirming the efficiency of the suggested strategy for distinguishing normal and pathological tissues from brain MR images; this is greater than the methods that are already in use. (shrink)

Hastings Center Report, Volume 52, Issue 3, Page 31-33, May–June 2022.

This paper, using the author's decomposition method and recent generalizations, presents algorithms for an analytic solution of the stochastic Navier-Stokes system without linearization, perturbation, discretization, or restrictive assumptions on the nature of stochasticity. The pressure, forces, velocities, and initial/boundary conditions can be stochastic processes and are not limited to white noise. Solutions obtained are physically realistic because of the avoidance of assumptions made purely for mathematical tractability by usual methods. Certain extensions and further generalizations of the decomposition method have provided (...) the basis for the solution. (shrink)

Inhalts: Vorwort. A. SCHRIFTEN FICHTES. I. Gesammelte Werke. II. Einzelausgaben. III. Fremdsprachige Ausgaben. B. LITERATUR ZU FICHTE. I. Publikationen zu Leben und Werk im allgemeinen. II. Untersuchungen zu einzelnen Sachgebieten. III. Fichte und andere Denker. C. REGISTER. ZEITSCHRIFTENVERZEICHNIS. NACHTRAG.

¡Cuán lejos estamos del clasicismo, y cuánto necesitamos de él! La necesidad de incorporar más estudios humanísticos es una necesidad que no puede sino sonar hoy terriblemente arcaica, inadaptada a los tiempos que –literalmente– corren, inútil a una democracia que ha perdido el rumbo y que trepida a la consolidación de lo técnico, donde la deliberación ha sido reemplazada por lo instintivo, por la irreflexión, por el espectáculo; en fin, si hay una consigna que hoy suena como una bella sinfonía (...) opacada por el ruido circundante, no es sino aquella que clama por la reivindicación del humanismo en nuestra educación como una condición ineludible de una democracia realmente deliberativa. Esto ya lo había atisbado nuestra poetisa, cuando señaló que las briznas apenas asomadas del humanismo fueron quemadas en varios países “y que lo científico entró con una presencia borrosa de fantasma, es decir, sin capacidad para suceder a la patrona arrojada de las aulas” (98). (shrink)

This volume presents new texts of Cicero's dialogues on political philosophy, De Re Publica and De Legibus, together with corrected versions of the editor's previously published editions of Cato Maior de Senectute and Laelius de Amicitia. The texts are based on a full reconsideration of the manuscript evidence and are presented in a clear and readable form.

Alexandrian epic is ‘arte allusiva’–to use the Pasqualian term—par excellence: the best methodological introduction to this literary feature still remains Herter's monograph. In the following pages I should like to show how certain passages from Callimachus or ApoUonius can be properly understood only if interpreted according to the canons of the ‘arte allusiva’ as practised by the poets.