The Algebra of Dimension-Linking Operators

1965 ◽  
Vol 8 (2) ◽  
pp. 203-222 ◽  
Author(s):  
R. H. Bruck

In the course of preparing a book on group theory [1] with special reference to the Restricted Burnside Problem and allied problems I stumbled upon the concept of a dimension-linking operator. Later, when I lectured to the Third Summer Institute of the Australian Mathematical Society [2], G. E. Wall raised the question whether the dimension-linking operators could be made into a ring by introduction of a suitable definition of multiplication. The answer was easily found to be affirmative; the result wasthat the theory of dimen sion-linking operators became exceedingly simple.

The action of an arbitrary (but finite or compact) group on an arbitrary Hilbert space is studied. The application of group theory to physical calculations is often based on the Wigner-Eckart theorem, and one of the aims is to lead up to a general proof of this theorem. The group’s action gives irreducible ket-vector representation spaces, products of which lead to a definition of coupling (Wigner, or Clebsch-Gordan) coefficients and jm and j symbols. The properties of these objects are studied in detail, beginning with properties that are independent of the basis chosen for the representation spaces. We then explore some of the consequences of choosing bases by using the action of a subgroup. This leads to the Racah factorization lemma and the definition of jm factors, also a general statement of Racah’s reciprocity. In the third part, we add to these ideas, some properties of the space of all linear operators taking the Hilbert space to itself. This leads to a proof of the Wigner—Eckart theorem which is both succinct and in the language of quantum mechanics.


1984 ◽  
Vol 49 (1) ◽  
pp. 317-321 ◽  
Author(s):  
Anand Pillay

2018 ◽  
pp. 4-7
Author(s):  
S. I. Zenko

The article raises the problem of classification of the concepts of computer science and informatics studied at secondary school. The efficiency of creation of techniques of training of pupils in these concepts depends on its solution. The author proposes to consider classifications of the concepts of school informatics from four positions: on the cross-subject basis, the content lines of the educational subject "Informatics", the logical and structural interrelations and interactions of the studied concepts, the etymology of foreign-language and translated words in the definition of the concepts of informatics. As a result of the first classification general and special concepts are allocated; the second classification — inter-content and intra-content concepts; the third classification — stable (steady), expanding, key and auxiliary concepts; the fourth classification — concepts-nouns, conceptsverbs, concepts-adjectives and concepts — combinations of parts of speech.


2011 ◽  
pp. 143-147
Author(s):  
L. G. Naumova ◽  
V. B. Martynenko ◽  
S. M. Yamalov

Date of «birth» of phytosociology (phytocenology) is considered to be 1910, when at the third International Botanical Congress in Brussels adopted the definition of plant association in the wording Including Flaó and K. Schröter (Flahault, Schröter, 1910; Alexandrov, 1969). The centenary of this momentous event in the history of phytocenology devoted to the 46th edition of the Yearbook «Braun-Blanquetia», which began to emerge in 1984 in Camerino (Italy) and it has a task to publish large geobotanical works. During the years of the publication of the Yearbook on its pages were published twice work of the Russian scientists — «The steppes of Mongolia» (Z. V. Karamysheva, V. N. Khramtsov. Vol. 17. 1995), and «Classification of continental hemiboreal forests of Northern Asia» (N. B. Ermakov in collaboration with English colleagues and J. Dring, J. Rodwell. Vol. 28. 2000).


Author(s):  
Al-KhaierAmer Abdul Kareem
Keyword(s):  

Abstract The research started with an introduction containing the statement of the problem. The study was divided into four parts: a preamble and three sections. The preamble involved a definition of the metaphorical image and its importance. The first section covered the sources of the metaphorical image, the second dealt with the types of the metaphorical image, and the third discussed the functions of metaphorical representation as well as the main tools that contributed to the construction and formation of the metaphorical image. Finally, the study ended with a conclusion comprising the most significant findings of this research. keyword: metaphorical image, AL-Sharif Al-Radi.


Mediaevistik ◽  
2020 ◽  
Vol 32 (1) ◽  
pp. 377-379
Author(s):  
Kriszta Kotsis

Late antique and early medieval graphic signs have traditionally been studied by narrowly focused specialists leading to the fragmentation and decontextualization of this important body of material. Therefore, the volume aims “to deepen interdisciplinary research on graphic signs” (7) of the third through tenth centuries, with contributions from archaeologists, historians, art historians, a philologist, and a paleographer. Ildar Garipzanov’s introduction defines the central terms (sign, symbol, graphicacy), calls for supplanting the text-image binary with “the concept of the visual-written continuum” (15), and argues that graphicacy was central to visual communication in this period. He emphasizes the agency of graphic signs and notes that their study can amplify our understanding of the definition of personal and group identity, the articulation of power, authority, and religious affiliation, and communication with the supernatural sphere.


Author(s):  
Anatoly S. Kuprin ◽  
Galina I. Danilina

The purpose of this study is the analysis of limit situation in the narrative of war. The material of the study is the novel of Daniil Granin “My Lieutenant” and related texts. In the first part of the paper, the authors explore existing approaches to the term “limit situation” and similar concepts into scientific and philosophical traditions; limits of its applicability in literary studies and its relation to the categories of “narrative instances” and “event”. Proposed a literary-theoretical definition of the limit situation, which can be used in the analysis of fiction texts. Existing approaches to the examination of the situation of war are analyzed: philosophical-existential, psychoanalytic, sociological, literary. In the second part of the paper, the authors propose their method for analyzing limit situations in texts about war, which basis on existing approaches and preserves the text-centric principle of studying the structure of the story. Two interrelated areas of research have been identified: the study of war as a continuous limit situation in the intertextual aspect (the discourse of war); the study of limit situations (death, suffering, guilt, accident) in the narrative of war as part of a specific text. In the third part of the scientific work,the analysis of war as a continuous limit situation results in the study of the concept of “limit” (border) in a fiction text. The role of “limit” (border) concept in the texts about the war is studied, the possible types of limits in the discourse of war are examined. Limit situations in the narrative of war are analyzed on the basis of the novel “My Lieutenant” by Daniil Granin. A review of journalistic and scientific works about the novel revealed both the continuity and the differences between the novel and the “lieutenant” prose of the 20th century. An analysis of the limit situations in the novel revealed their key position in the narrative. These situations are independent of the fiction time, of the fluctuation of the point of view’; the function of the abstract author is to build the narrative as a “directive” immersion of the hero and narrator in these situations.


2019 ◽  
Vol 29 (5) ◽  
pp. 135-150

The springboard for this essay is the author’s encounter with the feeling of horror and her attempts to understand what place horror has in philosophy. The inquiry relies upon Leonid Lipavsky’s “Investigation of Horror” and on various textual plunges into the fanged and clawed (and possibly noumenal) abyss of Nick Land’s work. Various experiences of horror are examined in order to build something of a typology, while also distilling the elements characteristic of the experience of horror in general. The essay’s overall hypothesis is that horror arises from a disruption of the usual ways of determining the boundaries between external things and the self, and this leads to a distinction between three subtypes of horror. In the first subtype, horror begins with the indeterminacy at the boundaries of things, a confrontation with something that defeats attempts to define it and thereby calls into question the definition of the self. In the second subtype, horror springs from the inability to determine one’s own boundaries, a process opposed by the crushing determinacy of the world. In the third subtype, horror unfolds by means of a substitution of one determinacy by another which is unexpected and ungrounded. In all three subtypes of horror, the disturbance of determinacy deprives the subject, the thinking entity, of its customary foundation for thought, and even of an explanation of how that foundation was lost; at times this can lead to impairment of the perception of time and space. Understood this way, horror comes within a hair’s breadth of madness - and may well cross over into it.


Author(s):  
Brian E. Daley, SJ

The Council of Chalcedon’s definition of the terms in which Nicene orthodoxy should conceive of Christ’s person remained controversial. Leontius of Byzantium argued for the correctness of the Council’s formulation, especially against the arguments of Severus of Antioch, but suggested that more than academic issues were at stake: the debate concerned the lived, permanently dialectical unity between God and humanity. In the mid-seventh century, imperially sponsored efforts to lessen the perceived impact of Chalcedonian language by stressing that Christ’s two natures were activated by “a single, theandric energy,” also remained without effect: largely because of the monk Maximus “the Confessor”, who argued that two complete spheres of activity and two wills remained evident in Christ’s life. Maximus’s position was ratified at the Lateran Synod and at the Third Council of Constantinople. The eighth-century Palestinian monk John of Damascus incorporated these arguments into his own influential synthesis of orthodox theology.


Author(s):  
James E. Baker

This article discusses covert action within the context of the U.S. law. The first section describes the main elements of the U.S. legal regime, including the definition of covert action and the “traditional activity” exceptions, the elements of a covert action finding, and the thresholds and requirements for congressional notification. The second section describes some of the significant limitations on the conduct of covert action. The third section discusses the nature of executive branch legal practice in this area of the law. And the last section draws conclusions about the role of national security law within the context of covert action.


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