Results 11 to 20 of about 421 (111)

Rationality, irrationality, and Wilf equivalence in generalized factor order [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2009
Let $P$ be a partially ordered set and consider the free monoid $P^{\ast}$ of all words over $P$. If $w,w' \in P^{\ast}$ then $w'$ is a factor of $w$ if there are words $u,v$ with $w=uw'v$. Define generalized factor order on $P^{\ast}$ by letting $u \leq
Sergey Kitaev   +3 more
doaj   +6 more sources

Egge triples and unbalanced Wilf-equivalence [PDF]

open access: yes, 2015
Egge conjectured that permutations avoiding the set of patterns $\{2143,3142,\tau\}$, where $\tau\in\{246135,254613,263514,524361,546132\}$, are enumerated by the large Schr\"oder numbers.
Bloom, Jonathan, Burstein, Alex
core   +3 more sources

On a refinement of Wilf-equivalence for permutations [PDF]

open access: yesThe Electronic Journal of Combinatorics, 2014
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.
Ge, Huiyun   +2 more
core   +4 more sources

Generating functions for Wilf equivalence under generalized factor order [PDF]

open access: yes, 2010
Kitaev, Liese, Remmel, and Sagan recently defined generalized factor order on words comprised of letters from a partially ordered set $(P, \leq_P)$ by setting $u \leq_P w$ if there is a subword $v$ of $w$ of the same length as $u$ such that the $i$-th ...
Langley, Thomas   +2 more
core   +4 more sources

Decreasing subsequences in permutations and Wilf equivalence for involutions [PDF]

open access: yesJournal of Algebraic Combinatorics, 2004
In a recent paper, Backelin, West and Xin describe a map $\phi ^*$ that recursively replaces all occurrences of the pattern $k... 21$ in a permutation $\sigma$ by occurrences of the pattern $(k-1)... 21 k$.
Bousquet-Melou, Mireille   +1 more
core   +4 more sources

Radiometric Constraints on the Timing, Tempo, and Effects of Large Igneous Province Emplacement

open access: yesGeophysical Monograph Series, Page 27-82., 2021

Exploring the links between Large Igneous Provinces and dramatic environmental impact

An emerging consensus suggests that Large Igneous Provinces (LIPs) and Silicic LIPs (SLIPs) are a significant driver of dramatic global environmental and biological changes, including mass extinctions.
Jennifer Kasbohm   +2 more
wiley  

+2 more sources

Bijections for generalized Wilf equivalences

open access: yesEnumerative Combinatorics and Applications
Starting 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
doaj   +3 more sources

On (shape-)Wilf-equivalence for words [PDF]

open access: yesAdvances in Applied Mathematics, 2018
AmS-LaTeX, 13 pages; minor ...
Guo, Ting   +2 more
openaire   +3 more sources

On refinements of wilf-equivalence for involutions

open access: yesJournal of Algebraic Combinatorics, 2023
Let $\mathcal{S}_n(π)$ (resp. $\mathcal{I}_n(π)$ and $\mathcal{AI}_n(π)$) denote the set of permutations (resp. involutions and alternating involutions) of length $n$ which avoid the permutation pattern $π$. For $k,m\geq 1$, Backelin-West-Xin proved that $|\mathcal{S}_n(12\cdots kτ)|= |\mathcal{S}_n(k\cdots 21τ)|$ by establishing a bijection between ...
Sherry H. F. Yan   +2 more
openaire   +2 more sources

Two examples of unbalanced Wilf-equivalence [PDF]

open access: yesJournal of Combinatorics, 2015
10 pages, minor revision, to appear in Journal of ...
Burstein, Alexander, Pantone, Jay
openaire   +2 more sources

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