1,524 research outputs found
Iterative Processes Related to Riordan Arrays: The Reciprocation and the Inversion of Power Series
We point out how Banach Fixed Point Theorem, and the Picard successive
approximation methods induced by it, allows us to treat some mathematical
methods in Combinatorics. In particular we get, by this way, a proof and an
iterative algorithm for the Lagrange Inversion Formula.Comment: 17 pages. We extend the results in the previuous version proving
finally the Lagrange Inversion Formula via Banach Fixed Point Theore
Finite entanglement entropy from the zero-point-area of spacetime
The calculation of entanglement entropy S of quantum fields in spacetimes
with horizon shows that, quite generically, S (a) is proportional to the area A
of the horizon and (b) is divergent. I argue that this divergence, which arises
even in the case of Rindler horizon in flat spacetime, is yet another
indication of a deep connection between horizon thermodynamics and
gravitational dynamics. In an emergent perspective of gravity, which
accommodates this connection, the fluctuations around the equipartition value
in the area elements will lead to a minimal quantum of area, of the order of
L_P^2, which will act as a regulator for this divergence. In a particular
prescription for incorporating L_P^2 as zero-point-area of spacetime, this does
happen and the divergence in entanglement entropy is regularized, leading to S
proportional to (A/L_P^2) in Einstein gravity. In more general models of
gravity, the surface density of microscopic degrees of freedom is different
which leads to a modified regularisation procedure and the possibility that the
entanglement entropy - when appropriately regularised - matches the Wald
entropy.Comment: ver 2: minor clarifications added; reformatted with Sections; 11
page
Searching the solution space in constructive geometric constraint solving with genetic algorithms
Geometric problems defined by constraints have an exponential number
of solution instances in the number of geometric elements involved.
Generally, the user is only interested in one instance such that
besides fulfilling the geometric constraints, exhibits some additional
properties.
Selecting a solution instance amounts to selecting a given root every
time the geometric constraint solver needs to compute the zeros of a
multi valuated function. The problem of selecting a given root is
known as the Root Identification Problem.
In this paper we present a new technique to solve the root
identification problem. The technique is based on an automatic search
in the space of solutions performed by a genetic algorithm. The user
specifies the solution of interest by defining a set of additional
constraints on the geometric elements which drive the search of the
genetic algorithm. The method is extended with a sequential niche
technique to compute multiple solutions. A number of case studies
illustrate the performance of the method.Postprint (published version
Features of ELF interactions in travel blogs: Travelers doing interactional work
Travel blogs constitute a new platform where travelers can tell about their travel experiences and share information and impressions with their readers. Most travel blogs incorporate commenting capabilities, which enable social interaction among members of communities with shared traveling interests. English is most often used as a Lingua Franca, facilitating interaction among people with different L1 backgrounds and transcending the native/non-native distinction. The purpose of this research is to analyze the features of English as a Lingua Franca (ELF) interactions in travel blogs and explore some strategies used by participants in blog discussions to achieve shared understanding and show belonging to an ELF community. The small corpus consists of 36 blog discussions taken from 12 blogs where the commenters belong to different L1 backgrounds. The corpus was analyzed qualitatively to determine whether some strategies used in ELF interactions (make it normal, backchanneling, codeswitching, and metacomments) occur in travel blogs and, if so, how they contribute to identity and community construction
Constructing academic identities online: Identity performance in research group blogs written by multilingual scholars
Blogs provide an open space for research groups to publicise their research and activities, become more visible both to the local and international disciplinary communities, and conduct self-promotion. Research groups harness the affordances of the medium to weave a narrative about the group, presented through various modalities, and thus construct their online identity. The purpose of this research is to analyse how identity is constructed in research group blogs written in English by groups affiliated to Spanish institutions. In this study I address the following questions: (i) which are the facets of the group''s identities created by multilingual scholars in research group blogs?; (ii) which textual and multimodal practices are adopted by researchers to construct the group''s identity? To answer these questions I conducted a content analysis (focusing on written language, visuals, hyperlinks) of posts taken from 12 research group blogs. The study provides insight on how these research groups mesh different semiotic modes in their blogs to project a multifaceted identity and reveals that blogging may be a powerful instrument for research groups’ identity performance and visibility
Academic Republicanism
Reseña de: Suárez Cortina, Manuel: Los caballeros de la razón. Cultura institucionista y democracia parlamentaria en la España liberal, Santander, Genueve Ediciones, 201
Llull, Ramon (2007): Raimundi Lulli Opera Latina. Tomus XXXII, 27. Ars demonstrativa. Edició de Josep Enric Rubio Albarracín. Turnhout: Brepols, LXXX + 352 p. (Corpus Christianorum, Continuatio Mediaevalis, 213)
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