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arXiv 1007.2492math.DS
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双曲平面型的分歧

Bifurcation of hyperbolic planforms

Pascal Chossat, Grégory Faye, Olivier Faugeras

摘要:

出于对灵长类动物的视觉皮层的纹理感知模型,我们分析了非线性方程描述的状态定义在空间的结构张量的系统的周期图案的分叉,当这些方程是进一步不变的相对于这个空间的等距。我们证明了该问题归结为双曲平面D(Poincaré盘)上的分歧问题。我们利用D中周期格的概念将问题进一步归结为紧致Riemann曲面D/T上的问题,其中T是余紧的无挠富克斯群.这个表面的对称群的知识允许进行机械的等变分歧理论。一般分叉的解称为“H-平面形”,与欧几里得空间中为形成图案而引入的“平面形”类似。这个概念被应用到一个八边形的周期性图案的情况下,在那里我们能够分类所有可能的H-planforms满足假设的等变分支引理。然而,这些模式是不简单的计算,即使是数字,在最后一节中,我们描述了一种计算方法,说明了一个选择的图像的八角形H-平面。

英文摘要:

Motivated by a model for the perception of textures by the visual cortex in primates, we analyse the bifurcation of periodic patterns for nonlinear equations describing the state of a system defined on the space of structure tensors, when these equations are further invariant with respect to the isometries of this space. We show that the problem reduces to a bifurcation problem in the hyperbolic plane D (Poincaré disc). We make use of the concept of periodic lattice in D to further reduce the problem to one on a compact Riemann surface D/T, where T is a cocompact, torsion-free Fuchsian group. The knowledge of the symmetry group of this surface allows to carry out the machinery of equivariant bifurcation theory. Solutions which generically bifurcate are called "H-planforms", by analogy with the "planforms" introduced for pattern formation in Euclidean space. This concept is applied to the case of an octagonal periodic pattern, where we are able to classify all possible H-planforms satisfying the hypotheses of the Equivariant Branching Lemma. These patterns are however not straightforward to compute, even numerically, and in the last section we describe a method for computation illustrated with a selection of images of octagonal H-planforms.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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