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北美退伍军人节(Veterans Day),12 日无更新
arXiv 1406.3787math.CO
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Tamari格的一个推广

An extension of Tamari lattices

Louis-François Préville-Ratelle, Xavier Viennot

摘要:

对于正方形网格上由北向和东向单位步组成的任何有限路$v$,从(0,0)开始,我们构造了一个偏序集Tam $(v)$,它由所有弱在$v$之上的路组成,其北向和东向步数与$v$相同.对于特定的选择$v$,我们恢复传统的Tamari晶格和$m$ -Tamari晶格。令$\overleftarrow{v}$为从$v$通过以相反顺序读取$v$的单位步阶获得的路径,用北步阶替换东步阶,反之亦然。证明了偏序集Tam $(v)$同构于偏序集Tam $(\overleftarrow{v})$的对偶.我们这样做的双射表明,偏序集谭$(v)$是同构的偏序集的基础上旋转的完整的二元树与固定的树冠$v$,从对偶容易遵循。这也表明Tam $(v)$是任何路径$v$的格。我们还得到作为这个双射的推论,通常的塔玛里格,根据戴克路径的高度$n$,是(较小的)格Tam $(v)$,其中$v$是所有的路径上的正方形网格组成的$n-1$单位步骤的分区。我们解释了偏序集Tam $(v)$和对称群的广义对角协不变空间(的组合学)之间可能的联系。

英文摘要:

For any finite path $v$ on the square grid consisting of north and east unit steps, starting at (0,0), we construct a poset Tam$(v)$ that consists of all the paths weakly above $v$ with the same number of north and east steps as $v$. For particular choices of $v$, we recover the traditional Tamari lattice and the $m$-Tamari lattice. Let $\overleftarrow{v}$ be the path obtained from $v$ by reading the unit steps of $v$ in reverse order, replacing the east steps by north steps and vice versa. We show that the poset Tam$(v)$ is isomorphic to the dual of the poset Tam$(\overleftarrow{v})$. We do so by showing bijectively that the poset Tam$(v)$ is isomorphic to the poset based on rotation of full binary trees with the fixed canopy $v$, from which the duality follows easily. This also shows that Tam$(v)$ is a lattice for any path $v$. We also obtain as a corollary of this bijection that the usual Tamari lattice, based on Dyck paths of height $n$, is a partition of the (smaller) lattices Tam$(v)$, where the $v$ are all the paths on the square grid that consist of $n-1$ unit steps. We explain possible connections between the poset Tam$(v)$ and (the combinatorics of) the generalized diagonal coinvariant spaces of the symmetric group.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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