Results 41 to 50 of about 206,672 (309)
Context-free grammars for permutations and increasing trees [PDF]
Advances in Applied Mathematics, 2014 In this paper, we introduce the notion of a grammatical labeling to describe a recursive process of generating combinatorial objects based on a context-free grammar. For example, by labeling the ascents and descents of a Stirling permutation, we obtain a
William Y. C. Chen, Amy M. Fu
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Determinant of binary circulant matrices
Special Matrices, 2019 This article gives a closed-form expression for the determinant of binary circulant matrices.
Hariprasad M.
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The Kendall and Mallows Kernels for Permutations
IEEE Transactions on Pattern Analysis and Machine Intelligence, 2015 We show that the widely used Kendall tau correlation coefficient, and the related Mallows kernel, are positive definite kernels for permutations. They offer computationally attractive alternatives to more complex kernels on the symmetric group to learn ...
Yunlong Jiao, Jean-Philippe Vert
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Profiles of Permutations [PDF]
The Electronic Journal of Combinatorics, 2009 This paper develops an analogy between the cycle structure of, on the one hand, random permutations with cycle lengths restricted to lie in an infinite set $S$ with asymptotic density $\sigma$ and, on the other hand, permutations selected according to the Ewens distribution with parameter $\sigma$.
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Almost commuting permutations are near commuting permutations [PDF]
, 2014 We prove that the commutator is stable in permutations endowed with the Hamming distance, that is, two permutations that almost commute are near two commuting permutations. Our result extends to k -tuples of almost commuting permutations, for any given k
G. Arzhantseva, Liviu Paunescu
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Permutation Reconstruction [PDF]
The Electronic Journal of Combinatorics, 2006 In this paper, we consider the problem of permutation reconstruction. This problem is an analogue of graph reconstruction, a famous question in graph theory. In the case of permutations, the problem can be stated as follows: In all possible ways, delete $k$ entries of the permutation $p=p_1p_2p_3...p_n$ and renumber accordingly, creating $n \choose k$
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Permutation Statistics of Indexed Permutations
European Journal of Combinatorics, 1994 The definitions of descent, exceedance, major index, inversion index and Denert's statistic for the elements of the symmetric group \({\mathcal S}_ d\) are generalized to indexed permutations, i.e. the elements of the group \(S^ n_ d:=\mathbb{Z}_ n\wr{\mathcal S}_ d\), where \(\wr\) is the wreath product with respect to usual action of \({\mathcal S}_ ...
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Permutations by Interchanges [PDF]
The Computer Journal, 1963 Methods for obtaining all possible permutations of a number of objects, in which each permutation differs from its predecessor only by the interchange of two of the objects, are discussed. Details of two programs which produce these permutations are given, one allowing a specified position to be filled by each of the objects in a predetermined order ...
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Finding small patterns in permutations in linear time [PDF]
ACM-SIAM Symposium on Discrete Algorithms, 2013 Given two permutations σ and π, the Permutation Pattern problem asks if σ is a subpattern of π. We show that the problem can be solved in time 2O(e2loge). n, where e = |σ| and n = |π|.
Sylvain Guillemot, D. Marx
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Covering n-Permutations with (n+1)-Permutations [PDF]
The Electronic Journal of Combinatorics, 2013 Let $S_n$ be the set of all permutations on $[n]:=\{1,2,\ldots,n\}$. We denote by $\kappa_n$ the smallest cardinality of a subset ${\cal A}$ of $S_{n+1}$ that "covers" $S_n$, in the sense that each $\pi\in S_n$ may be found as an order-isomorphic subsequence of some $\pi'$ in ${\cal A}$. What are general upper bounds on $\kappa_n$?
Taylor F. Allison +3 more
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