Results 11 to 20 of about 176,018 (136)
Enumeration of super-strong Wilf equivalence classes of permutations in the generalized factor order [PDF]
Discrete Mathematics & Theoretical Computer Science, 2019 Super-strong Wilf equivalence classes of the symmetric group ${\mathcal S}_n$ on $n$ letters, with respect to the generalized factor order, were shown by Hadjiloucas, Michos and Savvidou (2018) to be in bijection with pyramidal sequences of consecutive ...
Ioannis Michos, Christina Savvidou
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Wilf-equivalence for singleton classes [PDF]
Advances in Applied Mathematics, 2007 Given \(n\) and a permutation matrix \(M\) of rank less than \(n\), how many \(n \times n\) permutation matrices do \textit{not} have \(M\) as a submatrix? Letting \(S_n(M)\) be the set of \(n \times n\) permutation matrices not admitting \(M\) as a submatrix, we want \(| S_n(M)| \).
Guoce Xin, Julian West
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A new class of multiset Wilf equivalent pairs [PDF]
Discrete Mathematics, 2007 Let \(M\) be a multiset. A pair of patterns \((\sigma,\tau)\) is called multiset Wilf equivalent if, for any \(M\), the number of permutations of \(M\) that avoid \(\sigma\) is equal to the number of permutations of \(M\) that avoid \(\tau\). In this paper the author shows that if \(\sigma_{n-2}\) is a permutation of \(\{1^{x_1}, 2^{x_2},\dots, (n-2 ...
Venkateswaran, Vidya
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On a Refinement of Wilf-equivalence for Permutations [PDF]
The Electronic Journal of Combinatorics, 2015 Recently, Dokos et al. conjectured that for all $k, m\geq 1$, the patterns $ 12\ldots k(k+m+1)\ldots (k+2)(k+1) $ and $(m+1)(m+2)\ldots (k+m+1)m\ldots 21$ are $maj$-Wilf-equivalent. In this paper, we confirm this conjecture for all $k\geq 1$ and $m=1$.
Sherry H. F. Yan, Huiyun Ge, Yaqiu Zhang
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On Super-Strong Wilf Equivalence Classes of Permutations [PDF]
The Electronic Journal of Combinatorics, 2018 Super-strong Wilf equivalence is a type of Wilf equivalence on words that was originally introduced as strong Wilf equivalence by Kitaev et al. [Electron. J. Combin. 16(2)] in $2009$. We provide a necessary and sufficient condition for two permutations in $n$ letters to be super-strongly Wilf equivalent, using distances between letters within a ...
Demetris Hadjiloucas +2 more
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Discrete Mathematics & Theoretical Computer Science, 2019 Two permutations in a class are Wilf-equivalent if, for every size, $n$, the number of permutations in the class of size $n$ containing each of them is the same.
Michael Albert, Jinge Li
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On (Shape-)Wilf-Equivalence of Certain Sets of (Partially Ordered) Patterns [PDF]
The Electronic Journal of CombinatoricsWe prove a conjecture of Gao and Kitaev on Wilf-equivalence of sets of patterns $\{12345,12354\}$ and $\{45123,45213\}$ that extends the list of 10 related conjectures proved in the literature in a series of papers. To achieve our goals, we prove generalized versions of shape-Wilf-equivalence results of Backelin, West, and Xin and use a particular ...
Burstein, Alexander +3 more
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Decreasing Subsequences in Permutations and Wilf Equivalence for Involutions [PDF]
Journal of Algebraic Combinatorics, 2005 In a recent paper, Backelin, West and Xin describe a map $ϕ^*$ that recursively replaces all occurrences of the pattern $k... 21$ in a permutation $σ$ by occurrences of the pattern $(k-1)... 21 k$. The resulting permutation $ϕ^*(σ)$ contains no decreasing subsequence of length $k$.
Einar Steingrimsson +2 more
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Bijections for generalized Wilf equivalences
Enumerative Combinatorics and ApplicationsStarting with an inclusion-exclusion proof of a combinatorial identity, a direct bijection can be produced using recursive subtraction (sometimes with a direct combinatorial description). We apply this method to identities for generalized Wilf equivalences among consecutive patterns in inversion sequences, giving direct bijective proofs of some ...
Melanie Ferreri
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New Wilf-equivalence results for vincular patterns
European Journal of Combinatorics, 2013 zbMATH Open Web Interface contents unavailable due to conflicting licenses.
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