1,439 research outputs found

    A probabilistic approach to value sets of polynomials over finite fields

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    In this paper we study the distribution of the size of the value set for a random polynomial with degree at most q−1q-1 over a finite field Fq\mathbb{F}_q. We obtain the exact probability distribution and show that the number of missing values tends to a normal distribution as qq goes to infinity. We obtain these results through a study of a random rr-th order cyclotomic mappings. A variation on the size of the union of some random sets is also considered

    Lusztig correspondence and the Gan-Gross-Prasad problem

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    The Gan-Gross-Prasad problem is to describe the restriction of representations of a classical group GG to smaller groups HH of the same kind. In this paper, we solved the Gan-Gross-Prasad problem over finite fields completely. In previous work \cite{LW1,LW2,LW3,Wang}, we study the Gan-Gross-Prasad problem for unipotent representations of finite classical groups. The main tools used are the Lusztig correspondence as well as a formula of Reeder \cite{R} for the pairings of Deligne-Lusztig characters. We give a reduction decomposition of Reeder's formula, and deduce the Gan-Gross-Prasad problem for arbitrary representations from the unipotent representations by Lusztig correspondence

    A Provable Smoothing Approach for High Dimensional Generalized Regression with Applications in Genomics

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    In many applications, linear models fit the data poorly. This article studies an appealing alternative, the generalized regression model. This model only assumes that there exists an unknown monotonically increasing link function connecting the response YY to a single index XTβ∗X^T\beta^* of explanatory variables X∈RdX\in\mathbb{R}^d. The generalized regression model is flexible and covers many widely used statistical models. It fits the data generating mechanisms well in many real problems, which makes it useful in a variety of applications where regression models are regularly employed. In low dimensions, rank-based M-estimators are recommended to deal with the generalized regression model, giving root-nn consistent estimators of β∗\beta^*. Applications of these estimators to high dimensional data, however, are questionable. This article studies, both theoretically and practically, a simple yet powerful smoothing approach to handle the high dimensional generalized regression model. Theoretically, a family of smoothing functions is provided, and the amount of smoothing necessary for efficient inference is carefully calculated. Practically, our study is motivated by an important and challenging scientific problem: decoding gene regulation by predicting transcription factors that bind to cis-regulatory elements. Applying our proposed method to this problem shows substantial improvement over the state-of-the-art alternative in real data.Comment: 53 page
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