scholarly journals Nonreversible trees having a removable edge

Filomat ◽  
2018 ◽  
Vol 32 (10) ◽  
pp. 3717-3724
Author(s):  
Nenad Moraca

A relational structure is said to be reversible iff every bijective homomorphism (condensation) of that structure is an automorphism. In the case of a binary structure X = ?X,??, that is equivalent to the following statement: whenever we remove finite or infinite number of edges from X, thus obtaining the structure X', we have that X'?/ X. In this paper, we prove that if a nonreversible tree X = ?X,?? has a removable edge (i.e. if there is ?x,?? ? ? such that ?X,?? ? ?X,?\{?x,y?}?, then it has infinitely many removable edges. We also show that the same is not true for arbitrary binary structure by constructing nonreversible digraphs having exactly n removable edges, for n ? N.

2020 ◽  
Vol 43 ◽  
Author(s):  
Aba Szollosi ◽  
Ben R. Newell

Abstract The purpose of human cognition depends on the problem people try to solve. Defining the purpose is difficult, because people seem capable of representing problems in an infinite number of ways. The way in which the function of cognition develops needs to be central to our theories.


2006 ◽  
Author(s):  
Stella Christie ◽  
Dedre Gentner
Keyword(s):  

2018 ◽  
Vol 10 (1) ◽  
pp. 31-51
Author(s):  
Raphael Lataster

Theistic and analytic philosophers of religion typically privilege classical theism by ignoring or underestimating the great threat of alternative monotheisms.[1] In this article we discuss numerous god-models, such as those involving weak, stupid, evil, morally indifferent, and non-revelatory gods. We find that theistic philosophers have not successfully eliminated these and other possibilities, or argued for their relative improbability. In fact, based on current evidence – especially concerning the hiddenness of God and the gratuitous evils in the world – many of these hypotheses appear to be more probable than theism. Also considering the – arguably infinite – number of alternative monotheisms, the inescapable conclusion is that theism is a very improbable god-concept, even when it is assumed that one and only one transcendent god exists.[1] I take ‘theism’ to mean ‘classical theism’, which is but one of many possible monotheisms. Avoiding much of the discussion around classical theism, I wish to focus on the challenges in arguing for theism over monotheistic alternatives. I consider theism and alternative monotheisms as entailing the notion of divine transcendence.


Author(s):  
Loreta De Stasio

En este artículo examinaremos algunas de las principales estrategias discursivas empleadas en dos artículos publicados por U. Eco en L’Espresso, una revista semanal muy conocida en Italia de carácter político, social, cultural y económico, en el marco de una página personal titulada “La Bustina di Minerva”, es decir, “El Sobrecito de Minerva”. El título es una referencia a la comunicación breve, a las observaciones de cualquier tipo, pero igualmente, de forma simultánea. Los sobrecitos reflexionan sobre el mundo contemporáneo, la sociedad italiana, los medios de comunicación de masas; tratan de la actualidad y la relacionan con la historia y la filosofía, con Internet y el futuro del Tercer Milenio, y nos proponen los pensamientos de U. Eco con más viveza que una conferencia o un tratado.La ironía, la sátira y la parodia son las bases argumentativas de muchos “Sobrecitos”. Generalmente, el humor transmite dos sentidos a la vez. Detrás de una serie de textos tan variados temáticamente aparece a menudo una misma estructura binaria, un cuerpo dual. Con frecuencia, un mismo artículo obedece a una doble orientación tematica, ya que suelen mezclar dos motivos que pertenecen a áreas diferentes, alternando simultáneamente dos sujetos. A esta doble orientación temática del “Sobrecito” corresponde la doble orientación semántica de la palabra irónica que, junto con la parodia es un discurso dialógico o bi-direccional en el que se mezclan dos voces.In this article some of the main discursive strategies used in two articles published by U. Eco are examined. These articles have been published in L'Espresso, a weekly review very widespread in Italy, of political, social, cultural and economic character, within the framework of a column titled “La Bustina di Minerva”, that is to say, “The little bag/envelope of Minerva”. This title refers to a brief communication, to observations of any type, but also, immediate. The “bustine” reflects on the contemporary world, the Italian society, the mass media; they deal with present time and relate it to history and philosophy, Internet and the future of the Third Millennium, and they propose us Eco’s thoughts with more vividness than a conference or an essay.Irony, satire and parody are the argumentative bases of many “bustine”. Generally, humour transmits two senses simultaneously. Behind a series of texts so thematically varied there is often a same binary structure, a dual body. Frequently, a same article obeys to a double thematic direction, since usually they mix two arguments that belong to different areas, alternating two subjects simultaneously. To this double thematic direction of the “bustina” corresponds the double semantic direction of the ironic word that, along with parody, is a dialogic or bidirectional speech in which two voices are mixed.


10.37236/1184 ◽  
1994 ◽  
Vol 1 (1) ◽  
Author(s):  
Tomasz Łuczak

An elementary probabilistic argument is presented which shows that for every forest $F$ other than a matching, and every graph $G$ containing a cycle, there exists an infinite number of graphs $J$ such that $J\to (F,G)$ but if we delete from $J$ any edge $e$ the graph $J-e$ obtained in this way does not have this property.


Author(s):  
Ohad Nachtomy

This work presents Leibniz’s view of infinity and the central role it plays in his theory of living beings. Chapter 1 introduces Leibniz’s approach to infinity by presenting the central concepts he employs; chapter 2 presents the historical background through Leibniz’s encounters with Galileo and Descartes, exposing a tension between the notions of an infinite number and an infinite being; chapter 3 argues that Leibniz’s solution to this tension, developed through his encounter with Spinoza (ca. 1676), consists of distinguishing between a quantitative and a nonquantitative use of infinity, and an intermediate degree of infinity—a maximum in its kind, which sheds light on Leibniz’s use of infinity as a defining mark of living beings; chapter 4 examines the connection between infinity and unity; chapter 5 presents the development of Leibniz’s views on infinity and life; chapter 6 explores Leibniz’s distinction between artificial and natural machines; chapter 7 focuses on Leibniz’s image of a living mirror, contrasting it with Pascal’s image of a mite; chapter 8 argues that Leibniz understands creatures as infinite and limited, or as infinite in their own kind, in distinction from the absolute infinity of God; chapter 9 argues that Leibniz’s concept of a monad holds at every level of reality; chapter 10 compares Leibniz’s use of life and primitive force. The conclusion presents Leibniz’s program of infusing life into every aspect of nature as an attempt to re-enchant a view of nature left disenchanted by Descartes and Spinoza.


Author(s):  
Adi Ophir ◽  
Ishay Rosen-Zvi

This chapter sets the stage for a detailed analysis of the rabbinic goy. It traces the consolidation of the binary relation and the exclusion of hybrid categories. It further traces the rabbinic tendency to erase intermediate categories (Samaritans; foreign slaves; God-fearers; heretics) and force them into the new binary formation. From this perspective a new reading of the conversion ceremony is also offered. First appearing in rabbinic literature, the ceremony transformed diffusive spaces of conversion into a sharp and unequivocal procedure of passage—a transitory, instant event. Instead of reading this procedure as an evidence of a permeable border between groups, as scholars tend to do, the chapter shows how it performs the very erection of this border as it regulates its crossing.


2013 ◽  
Vol 479-480 ◽  
pp. 1193-1196
Author(s):  
Hsiang Chuan Liu ◽  
Yen Kuei Yu ◽  
Hsien Chang Tsai

In this paper, an extensional item relational structure theory based on the improved nonparametric item response theory is proposed. Item relational structure theory (Takeya, 1991) was developed to detect item relational structures of a group of subjects. The differences of these structures and experts knowledge structures can provide more information for planning remedial instruction, developing instruction materials, or educational researches. In this study, Lius improved nonparametric item response theory ( Liu, 2000, 2013) without the local independence assumption is used to estimate the joint probability of two items, and construct personal item relational structures. A Mathematics example is also provided in this paper to illustrate the advantages of the proposed method


1989 ◽  
Vol 03 (15) ◽  
pp. 1185-1188 ◽  
Author(s):  
J. SEIMENIS

We develop a method to find solutions of the equations of motion in Hamiltonian Dynamical Systems. We apply this method to the system [Formula: see text] We study the case a → 0 and we find that in this case the system has an infinite number of period dubling bifurcations.


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