scholarly journals Eigenvalues of Hermitian matrices and equivariant cohomology of Grassmannians

2013 ◽  
Vol 149 (9) ◽  
pp. 1569-1582 ◽  
Author(s):  
David Anderson ◽  
Edward Richmond ◽  
Alexander Yong

AbstractThe saturation theorem of Knutson and Tao concerns the nonvanishing of Littlewood–Richardson coefficients. In combination with work of Klyachko, it implies Horn’s conjecture about eigenvalues of sums of Hermitian matrices. This eigenvalue problem has a generalization to majorized sums of Hermitian matrices, due to S. Friedland. We further illustrate the common features between these two eigenvalue problems and their connection to Schubert calculus of Grassmannians. Our main result gives a Schubert calculus interpretation of Friedland’s problem, via equivariant cohomology of Grassmannians. In particular, we prove a saturation theorem for this setting. Our arguments employ the aforementioned work together with recent work of H. Thomas and A. Yong.

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
M. Aliyari ◽  
M. Ghasemi Kamalvand

We describe an indefinite state of Arnoldi’s method for solving the eigenvalues problems. In the following, we scrutinize the indefinite state of Lanczos’ method for solving the eigenvalue problems and we show that this method for the J-Hermitian matrices works much better than Arnoldi’s method.


Author(s):  
Graeme D. Ruxton ◽  
William L. Allen ◽  
Thomas N. Sherratt ◽  
Michael P. Speed

Aposematism is the pairing of two kinds of defensive phenotype: an often repellent secondary defence that typically renders prey unprofitable to predators if they attack them and some evolved signal that indicates the presence of that defence. Aposematic signals often work to modify the behaviours of predators both before and during attacks. Warning coloration, for example, may increase wariness and hence improve the chances that a chemically defended prey is released unharmed after an attack. An aposematic signal may therefore first tend to reduce the probability that a predator commences attack (a primary defence) and then (as a component of secondary defence) reduce the probability that the prey is injured or killed during any subsequent attack. In this chapter we will consider both the primary and the secondary effects of aposematic signals on prey protection. We begin first by describing the common features of aposematic signals and attempting to show the wide use to which aposematic signalling is deployed across animals (and perhaps plants too). We then review the interesting evolutionary issues aposematic signals raise, including their initial evolution and their integration with sexual and other signals. We also discuss important ecological, co-evolutionary, and macroevolutionary consequences of aposematism.


Author(s):  
Sarah E. Murray

This book gives a compositional, truth‐conditional, crosslinguistic semantics for evidentials set in a theory of the semantics for sentential mood. Central to this semantics is a proposal about a distinction between what propositional content is at‐issue, roughly primary or proffered, and what content is not‐at‐issue. Evidentials contribute not‐at‐issue content, more specifically what I will call a not‐at‐issue restriction. In addition, evidentials can affect the level of commitment a sentence makes to the main proposition, contributed by sentential mood. Building on recent work in the formal semantics of evidentials and related phenomena, the proposed semantics does not appeal to separate dimensions of illocutionary meaning. Instead, I argue that all sentences make three contributions: at‐issue content, not‐at‐issue content, and an illocutionary relation. At‐issue content is presented, made available for subsequent anaphora, but is not directly added to the common ground. Not‐at‐issue content directly updates the common ground. The illocutionary relation uses the at‐issue content to impose structure on the common ground, which, depending on the clause type (e.g., declarative, interrogative), can trigger further updates. Empirical support for this proposal comes from Cheyenne (Algonquian, primary data from the author’s fieldwork), English, and a wide variety of languages that have been discussed in the literature on evidentials.


2021 ◽  
Vol 5 (1) ◽  
pp. 43-51
Author(s):  
Jeong-A Jo

This study aims to examine the common features and differences in how the Chinese-character classifier ‘ ben 本’ is used in Chinese, Korean, and Japanese, and will explore the factors that have affected the categorization processes and patterns of the classifier ‘ ben 本.’ Consideration of the differences in the patterns of usage and categorization of the same Chinese classifier in different languages enables us to look into the perception of the world and the socio cultural differences inherent in each language, the differences in the perception of Chinese characters, and the relationship between classifiers.


Author(s):  
Kelly Cline ◽  
Holly Zullo ◽  
David A Huckaby

Abstract Common student errors and misconceptions can be addressed through the method of classroom voting, in which the instructor presents a multiple-choice question to the class, and after a few minutes for consideration and small-group discussion, each student votes on the correct answer, using a clicker or a phone. If a large number of students have voted for one particular incorrect answer, the instructor can recognize and address the issue. In order to identify multiple-choice questions that are especially effective at provoking common errors and misconceptions, we recorded the percentages of students voting for each option on each question used in 25 sections of integral calculus, taught by 7 instructors, at 4 institutions, over the course of 12 years, on a collection of 172 questions. We restricted our analysis to the 115 questions which were voted on by at least 5 different classes. We present the six questions that caused the largest percentages of students to vote for a particular incorrect answer, discuss how we used these questions in the classroom, and examine the common features of these questions. Further, we look for correlations between question characteristics and the mean percentage of students voting for common errors on these questions, and we find that questions based on general cases have higher percentages of students voting for common errors.


2014 ◽  
Vol 70 (8) ◽  
pp. 58-61
Author(s):  
Aina Mardia Akhmad Aznan ◽  
Zanariah Abdullah ◽  
Vannajan Sanghiran Lee ◽  
Edward R. T. Tiekink

The title compound, C12H11N3O2, is a second monoclinic polymorph (P21, withZ′ = 4) of the previously reported monoclinic (P21/c, withZ′ = 2) form [Akhmad Aznanet al.(2010).Acta Cryst.E66, o2400]. Four independent molecules comprise the asymmetric unit, which have the common features of asyndisposition of the pyridine N atom and the toluene ring, and an intramolecular amine–nitro N—H...O hydrogen bond. The differences between molecules relate to the dihedral angles between the rings which range from 2.92 (19) to 26.24 (19)°. The geometry-optimized structure [B3LYP level of theory and 6–311 g+(d,p) basis set] has the same features except that the entire molecule is planar. In the crystal, the three-dimensional architecture is consolidated by a combination of C—H...O, C—H...π, nitro-N—O...π and π–π interactions [inter-centroid distances = 3.649 (2)–3.916 (2) Å].


2021 ◽  
pp. 251385022098177
Author(s):  
Jeong-A Jo

This study aims to examine the common features and differences in how the Chinese-character classifier ‘ ben 本’ is used in Chinese, Korean, and Japanese, and will explore the factors that have affected the categorization processes and patterns of the classifier ‘ ben 本.’ Consideration of the differences in the patterns of usage and categorization of the same Chinese classifier in different languages enables us to look into the perception of the world and the socio cultural differences inherent in each language, the differences in the perception of Chinese characters, and the relationship between classifiers.


1952 ◽  
Vol 98 (413) ◽  
pp. 515-564 ◽  
Author(s):  
P. M. Yap

Few mental diseases have attracted the attention of medical men working in outlandish parts of the world more than Latah. This is due, not only to its intrinsic interest, showing as it regularly does the unusual symptoms of echolalia, echopraxia, and automatic obedience, but also to its remarkable geographical distribution. This illness was described by travellers to the Malay Archipelago in the latter part of the nineteenth century, but very similar reactions were later found to exist in other lands, known to the native peoples by other names. The term “Latah,” however, is the best known, and as the common features between these various reactions became apparent, it has been used as an inclusive name for them all. It is to-day employed with much the same connotation in the French, Dutch, Italian, and English literature, but the discussion of its nature betrays inadequate understanding, attempts at its nosological classification remain unsatisfactory, and speculations as to its aetology continue to be somewhat fanciful.


2013 ◽  
Vol 8 (1) ◽  
pp. 42-54
Author(s):  
Camille Carbonnaux

Since the 1990s, European judicial and normative institutions have paid particular attention to the competitive practices of public undertakings. Consequently, their regime is governed by a significant number of rules pursuing objectives appearing, a priori, contradictory. In fact, public undertakings may experience difficulties in their management. In this context, an approach of public competition law through the prism of fair competition can be very useful. Regarding the uniformity of its judgment, fair competition appears as an objective capable of coordinating rules and overcoming their contradictions. It thereby offers a global and coherent reading plan of all the legal translations of the European competitive order being of some practical importance. In illuminating the common features of the different legal aspects of competition, we can easily switch from one to the other. It therefore makes the European approach to competition more accessible and understandable. Furthermore, and most importantly, it leads to identifying legal opportunities and threats in a cross-disciplinary way. So, from a “Law & Management” perspective, it appears to be a precious tool for the management of public undertakings. Key words: European competition law, public undertakings, fair competition, “Management & law”.


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