Search results for "Recursion"
showing 10 items of 61 documents
SUSY Ward identities for multi-gluon helicity amplitudes with massive quarks
2006
We use supersymmetric Ward identities to relate multi-gluon helicity amplitudes involving a pair of massive quarks to amplitudes with massive scalars. This allows to use the recent results for scalar amplitudes with an arbitrary number of gluons obtained by on-shell recursion relations to obtain scattering amplitudes involving top quarks.
MR 2944715 Reviewed Zhu S. On the recursion formula for double Hurwitz numbers. Proceedings of the American Mathematical Society (2012) 140, no. 11, …
2013
Let $\mu = (\mu_{1}, \mu_{2}, \ldots, \mu_{m})$ and $\nu = (\nu_{1}, \nu_{2}, \ldots, \nu_{n})$ be two partitions of a positive integer $d$. In this paper, the author considers degree $d$ branched coverings of $\mathbb{P}^{1}$ with at most two special points, $0$ and $\infty$. Specifically, the purpose of the author is to give a recursion formula for double Hurwitz numbers $H^{g}_{\mu, \nu}$ by the cut-join analysis. Here, $H^{g}_{\mu, \nu}$ denotes the number of genus $g$ branched covers of $\mathbb{P}^{1}$ with branching date corresponding to $\mu$ and $\nu$ over $0$ and $\infty$, respectively. Furthemore, as application, the author gets a polynomial identity for linear Goulden-Jackson-Va…
Introduction
2017
The book is devoted to three key questions concerning the relationship between complexity and natural language. Briefly, such questions are: (a) What kind of complexity for natural language? (b) Which theory of language in the perspective of complexity? (c) What sorts of methods and models in the analysis of the observed phenomena? All the essays in this volume show the reference to complexity as a constant element. However, the use of the singular may not be entirely appropriate.
Le métier de linguiste.
2021
The paper aims to analyze the epistemological status of theoretical linguistics.
Is recursion language-specific? Evidence of recursive mechanisms in the structure of intentional action
2014
In their 2002 seminal paper Hauser, Chomsky and Fitch hypothesize that recursion is the only human-specific and language-specific mechanism of the faculty of language. While debate focused primarily on the meaning of recursion in the hypothesis and on the human-specific and syntax-specific character of recursion, the present work focuses on the claim that recursion is language-specific. We argue that there are recursive structures in the domain of motor intentionality by way of extending John R. Searle's analysis of intentional action. We then discuss evidence from cognitive science and neuroscience supporting the claim that motor-intentional recursion is language-independent and suggest so…
Centre-embedded structures are a by-product of associative learning and working memory constraints: Evidence from baboons (Papio Papio)
2012
International audience; Influential theories have claimed that the ability for recursion forms the computational core of human language faculty distinguishing our communication system from that of other animals (Hauser, Chomsky, & Fitch, 2002). In the present study, we consider an alternative view on recursion by studying the contribution of associative and working memory processes. After an intensive paired-associate training with visual shapes, we observed that baboons spontaneously ordered their responses in keeping with a recursive, centre-embedded structure. This result suggests that the human ability for recursion might partly if not entirely originate from fundamental processing cons…
Reducing the irreducible: Dispersed metal atoms facilitate reduction of irreducible oxides.
2021
Oxide reducibility is a central concept quantifying the role of the support in catalysis. While reducible oxides are often considered catalytically active, irreducible oxides are seen as inert supports. Enhancing the reducibility of irreducible oxides has, however, emerged as an effective way to increase their catalytic activity while retaining their inherent thermal stability. In this work, we focus on the prospect of using single metal atoms to increase the reducibility of a prototypical irreducible oxide, zirconia. Based on extensive self-consistent DFT+U calculations, we demonstrate that single metal atoms significantly improve and tune the surface reducibility of zirconia. Detailed ana…
Verification of Well-Formed Communicating Recursive State Machines
2008
AbstractIn this paper we introduce a new (non-Turing equivalent) formal model of recursive concurrent programs called well-formed communicating recursive state machines (CRSM). CRSM extend recursive state machines (RSM) by allowing a restricted form of concurrency: a state of a module can be refined into a finite collection of modules (working in parallel) in a potentially recursive manner. Communication is only possible between the activations of modules invoked on the same fork. We study the model-checking problem of CRSM with respect to specifications expressed in a temporal logic that extends CaRet with a parallel operator (ConCaRet). We propose a decision algorithm that runs in time ex…
Suffixes, Conjugates and Lyndon Words
2013
In this paper we are interested in the study of the combinatorial aspects connecting three important constructions in the field of string algorithms: the suffix array, the Burrows-Wheeler transform (BWT) and the extended Burrows-Wheeler transform (EBWT). Such constructions involve the notions of suffixes and conjugates of words and are based on two different order relations, denoted by $\plex$ and $\pom$, that, even if strictly connected, are quite different from the computational point of view. In this study an important role is played by Lyndon words. In particular, we improve the upper bound on the number of symbol comparisons needed to establish the $\pom$ order between two primitive wo…
Drawing and extruding: Theoretical and approximate formulas
1969
The problem of drawing of wires and of strips has been treated in several studies; among these the studies of Sachs seem essential. However, the results deduced according to similar theories are not always in accordance with the experimental results: reduction of area or of thickness are in fact usually smaller than those resulting from the theory. This is in dependance of the fact that Sachs has adopted the Limiting Condition of Yielding by v. Mises, according to which the limit values of stress in traction and compression are equal. More recently other AA. (Alberti, Noto La Diega, Bugini), admitting the Limiting Condition of Yielding by A. (or of the Paraboloid of Revolution) of which we …