891 research outputs found
Cheeger's energy on the Harmonic Sierpinski Gasket
Koskela and Zhou have proven that, on the harmonic Sierpinski gasket with
Kusuoka's measure, the "natural" Dirichlet form coincides with Cheeger's
energy. We give a different proof of this result, which uses the properties of
the Lyapounov exponent of the gasket
Young measures, Cartesian maps, and polyconvexity
We consider the variational problem consisting of minimizing a polyconvex
integrand for maps between manifolds. We offer a simple and direct proof of the
existence of a minimizing map. The proof is based on Young measures
Harmonic embeddings of the Stretched Sierpinski gasket.
P. Alonso-Ruiz, U. Freiberg and J. Kigami have defined a large family of resistance forms on the Stretched Sierpinski Gasket . In the present paper we introduce a system of coordinates on (technically, an embedding of into ) such that
\noindent) these forms are defined on and
\noindent) all affine functions are harmonic for them.
We do this adapting a standard method from the Harmonic Sierpinski Gasket: we start finding a sequence of pre-fractals such that all affine functions are harmonic on
. After showing that this property is inherited by the stretched harmonic gasket , we use the formula for the Laplacian of a composition to prove that, for a natural measure
on , C^2(\R^2,\R)\subset\dc(\Delta) and Teplyaev's formula for the Laplacian of functions holds. Lastly, we use the expression for to show that the form we have found is closable in
Another point of view on Kusuoka's measure
Kusuoka's measure on fractals is a Gibbs measure of a very special kind,
because its potential is discontinuous, while the standard theory of Gibbs
measures requires continuous (actuallly, H\"older) potentials. In this paper,
we shall see that for many fractals it is possible to build a class of
matrix-valued Gibbs measures completely within the scope of the standard
theory; there are naturally some minor modifications, but they are only due to
the fact that we are dealing with matrix-valued functions and measures. We
shall use these matrix-valued Gibbs measures to build self-similar Dirichlet
forms on fractals. Moreover, we shall see that Kusuoka's measure can be
recovered in a simple way from the matrix-valued Gibbs measure
Another point of view on Kusuoka's measure.
Kusuoka's measure on fractals is a Gibbs measure of a very special kind, since its potential is discontinuous while the standard theory of Gibbs measures requires continuous (in its simplest version, H\"older) potentials. In this paper we shall see that for many fractals it is possible to build a class of matrix-valued Gibbs measures completely within the scope of the standard theory; there are naturally some minor modifications, but they are only due to the fact that we are dealing with matrix-valued functions and measures. We shall use these matrix-valued Gibbs measures to build self-similar bilinear forms on fractals. Moreover, we shall see that Kusuoka's measure and bilinear form can be recovered in a simple way from the matrix-valued Gibbs measure
Laterality in artistic gymnastics
Worldwide trainers ask if there is a rotation scheme, which facilitate the learning of the elements with longitudinal rotations. Although there are some research on it, they did not attempt to verify a total scheme, but merely to see the relationship between two elements or four elements. In this study we analyse the appreciation of experts N = 161 coaches (age: 34.9 ± 10.9) from different levels of expertise and from different countries (ARG, BOL, BRA, CHI, ECU, ELS, GER, GUA, HON, MEX, PAN, PER, URU, VEN) with 12 ± 8.8 years of experience regardinghow gymnasts should execute 27 different elements in 5 male apparatus. We chose these elements, because we wanted to have movements with rotation in upright stance, upside down and in combination with transversal rotation. Through a questionnaire for coaches, we tried to verify if there are differences, coincidences or even immovable rules in the rotation scheme that gymnasts use (or should use). The answers were typologized with three categories of rotational preference: unilateral consistent twister, bilateral consistent twister and inconsistent twister. The study aimed to answer several questions: Do coaches agree on how the rotation scheme should be in gymnastics? How do coaches (former gymnasts) determined which way to turn? Do the handedness or the footedness influence on the direction of rotation? Does the personal rotation scheme influence on the concept of appropriate rotation scheme? Do the national practices influence the rotation scheme? Are there differences in appreciation between coaches at different levels? Are unambiguous rules among the elements?Técnicos do mundo todo questionam se há um esquema de rotação, que facilita a aprendizagem dos elementos nas rotações longitudinais. As pesquisas sobre o assunto verificam a relação entre dois a quatro elementos daquelas, então, neste estudo, analisamos a apreciação de especialistas n = 161 treinadores (idade: 34,9 ± 10,9) de diferentes nÃveis de especialização e de diferentes paÃses (ARG, BOL, BRA, CHI, ECU, ELS, GER, GUA, HON, MEX, PAN , PER, URU, VEN) com 12 ± 8,8 anos de experiência a respeito de como um ginasta deve executar 27 diferentes elementos em cinco aparelhos masculinos. Escolhemos esses elementos, pois desejávamos investigar movimentos com rotação na posição em pé, de cabeça para baixo e em combinação com a rotação transversal. Por meio de um questionário para técnicos, averiguamos se existem diferenças, coincidências ou regras ainda imóveis no esquema de rotação que ginastas devem usar (ou deveriam usar). As respostas foram conceituadas em três categorias de preferência de rotação: rotação consistente unilateral, rotação consistente bilateral e rotação inconsistente. O estudo teve como objetivo responder a várias perguntas: Os técnicos concordam em relação a qual esquema de rotação deve estar na ginástica? Como técnicos (ex-ginastas) determinaram que caminho tomar? O posicionamento das mãos e dos pés influenciam na rotação? O modelo individual de rotação influência no conceito apropriado de rotação? As práticas nacionalizadas influênciam em um modelo de rotação? Existem diferenças na apreciação entre técnicos de diferentes nÃveis? Há regras ambÃguas entre os elementos
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