论文标题

Fisher几何模型中健身最大值的数量分布

Distribution of the number of fitness maxima in Fisher's Geometric Model

论文作者

Park, Su-Chan, Hwang, Sungmin, Krug, Joachim

论文摘要

Fisher的几何模型通过将从基因型离散空间与$ n $维的欧几里得表型空间与非线性,单峰表型拟合图相结合,描述了生物适应性景观。基因型由长度$ L $的二进制序列表示,并且不同位点突变的表型效应由从各向异性高斯分布中绘制的$ L $随机矢量表示。最近的工作表明,基因型和表型水平之间的相互作用会导致一系列不同的景观地形,这些景观的特征是局部适应性最大值的数量。扩展我们先前对本地最大值的平均数量的研究,在这里,我们关注的是,当限制$ l \ to \ fo \ infty $以有限$ n $进行时,我们将重点介绍最大值的分布。我们确定一般$ n $的最大值的典型尺度,并确定一维情况的最大值密度和最大值的两个点相关函数。我们还详细介绍了该模型与抗铁磁性霍普菲尔德模型的密切关系,并使用$ n $随机连续的模式向量,并证明我们的许多结果都延续到了此设置。更普遍地,我们期望我们的分析可以帮助阐明各种自旋玻璃问题中亚稳态状态的波动结构。

Fisher's geometric model describes biological fitness landscapes by combining a linear map from the discrete space of genotypes to an $n$-dimensional Euclidean phenotype space with a nonlinear, single-peaked phenotype-fitness map. Genotypes are represented by binary sequences of length $L$, and the phenotypic effects of mutations at different sites are represented by $L$ random vectors drawn from an isotropic Gaussian distribution. Recent work has shown that the interplay between the genotypic and phenotypic levels gives rise to a range of different landscape topographies that can be characterised by the number of local fitness maxima. Extending our previous study of the mean number of local maxima, here we focus on the distribution of the number of maxima when the limit $L \to \infty$ is taken at finite $n$. We identify the typical scale of the number of maxima for general $n$, and determine the full scaled probability density and two point correlation function of maxima for the one-dimensional case. We also elaborate on the close relation of the model to the anti-ferromagnetic Hopfield model with $n$ random continuous pattern vectors, and show that many of our results carry over to this setting. More generally, we expect that our analysis can help to elucidate the fluctuation structure of metastable states in various spin glass problems.

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