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non-group-theoretical_hyperoctahedral_categories_of_partitions [2020/01/23 10:56]
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non-group-theoretical_hyperoctahedral_categories_of_partitions [2021/11/23 11:56] (current)
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 ====== Non-group-theoretical hyperoctahedral categories of partitions ====== ====== Non-group-theoretical hyperoctahedral categories of partitions ======
  
-The **non-group-group-theoretical hyperoctahedral categories** are a one-parameter family of [[category_of_partitions|Banica-Speicher categories of partitions]],​ indexed by the natural numbers with infinity, introduced by Raum and Weber in [(:​ref:​RaWe16)].+The **non-group-theoretical hyperoctahedral categories** are a one-parameter family of [[category_of_partitions|Banica-Speicher categories of partitions]],​ indexed by the natural numbers with infinity, introduced by Raum and Weber in [(:​ref:​RaWe16)].
  
 ===== Definition ===== ===== Definition =====
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 For every $l\in \N\cup\{\infty\}$ a partition $p\in\Pscr$ is said to belong to the set of morphisms of the **non-group-theoretical hyperoctahedral category with parameter** $l$ if the following conditions are met: For every $l\in \N\cup\{\infty\}$ a partition $p\in\Pscr$ is said to belong to the set of morphisms of the **non-group-theoretical hyperoctahedral category with parameter** $l$ if the following conditions are met:
-  * $p$ has **blocks of even size**i.e. every block of $p$ has even number of legs.  +  * $p$ has //blocks of even size//,  ​meaning ​$|B|\in 2\Nfor every block $B$ of $p$ (see [[category ​of partitions ​with blocks of even size]]) ​.
-  * $p$ has **even distances between legs**. This property has been expressed in three different but equivalent ways: +
-    * For any given block $B$ of $p$ only evenly many blocks $B'$ of $p$ with $B\neq B'$ exist which cross $B$, i.e., such that one can find $i,j\in B$ and $i',​j'​\in B'with $i\prec i'​\prec j$ and $i'​\prec j\prec j'$ (where $\cdot\!\prec\!\cdot\!\prec\!\cdot$ is the cyclic order of $p$). +
-    * For any block $B$ of $p$ and any two legs $i,j\in B$ there is an even number of points located between $i$ and $j$, i.e. in the interval $]i,j[_p$ given by the set $\{ k\,\vert\, i\prec k\prec j\}$. +
-    * If one labels the points ​of $p$ in alternating fashion ​with one of two symbols $\oplus$ and $\ominus$ along the cyclic order of $p$, then blocks of $p$ may only join points with unequal labels.+
   * $p$ has the property that for all blocks $B$ and $B'$ of $p$ with $B\neq B'$ and all legs $i,j\in B$ with $i\neq j$ the set $[i,​j]_p\cap B'$ has even cardinality (which includes $0$), where $[i,j]=\{ k\,\vert\, i\preceq k\preceq j\}$. In other words, between any two legs of one block any other block may only have evenly many legs.   * $p$ has the property that for all blocks $B$ and $B'$ of $p$ with $B\neq B'$ and all legs $i,j\in B$ with $i\neq j$ the set $[i,​j]_p\cap B'$ has even cardinality (which includes $0$), where $[i,j]=\{ k\,\vert\, i\preceq k\preceq j\}$. In other words, between any two legs of one block any other block may only have evenly many legs.
   * $p$ satisfies $\mathrm{wdepth}(p)\leq l$, which means that $p$ contains no W of depth larger than $l$ if $l\in\N$ and which is a vacuous condition if $l=\infty$. For every $k\in\N$ we say that $p$ **contains a W of depth** $k$ if there exist letters $a_1,​\ldots,​a_k$ and words $X_1^\alpha,​\ldots,​ X_k^\alpha$,​ $X_1^\beta,​\ldots,​X_{k-1}^\beta$,​ $X_1^\gamma,​\ldots,​ X_k^\gamma$,​ $X_1^\delta,​\ldots,​ X_{k-1}^\delta$ and $Y_1$, $Y_2$, $Y_3$ such that    * $p$ satisfies $\mathrm{wdepth}(p)\leq l$, which means that $p$ contains no W of depth larger than $l$ if $l\in\N$ and which is a vacuous condition if $l=\infty$. For every $k\in\N$ we say that $p$ **contains a W of depth** $k$ if there exist letters $a_1,​\ldots,​a_k$ and words $X_1^\alpha,​\ldots,​ X_k^\alpha$,​ $X_1^\beta,​\ldots,​X_{k-1}^\beta$,​ $X_1^\gamma,​\ldots,​ X_k^\gamma$,​ $X_1^\delta,​\ldots,​ X_{k-1}^\delta$ and $Y_1$, $Y_2$, $Y_3$ such that 
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     * where $Y_1$, $Y_2$ and $Y_3$ contain none of the letters $a_1,​\ldots,​a_k$.     * where $Y_1$, $Y_2$ and $Y_3$ contain none of the letters $a_1,​\ldots,​a_k$.
  
-Any such partition is necessarily of //even size//. Moreover, if $l\leq 1$, then it is also //​non-crossing//​ (see [[category of all non-crossing partitions]].)+Any such partition is necessarily of [[category of partitions of even size|even size]] and has [[category of partitions with blocks of even size and even distances between legs|parity-balanced legs]]. Moreover, if $l\leq 1$, then it is also [[category of all non-crossing partitions|non-crossing]].
  
 ===== Canonical Generator ===== ===== Canonical Generator =====
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 ===== Associated easy quantum group ===== ===== Associated easy quantum group =====
  
-Via [[tannaka_krein_duality|Tannaka-Krein duality]] for compact quantum groups, for every $l\in\N\cup\{\infty\}$ the non-group-theoretical hyperoctahedral category with parameter $l$ corresponds to a family of [[non-group-theoretical hyperoctahedral easy quantum group|non-group-theoretical hyperoctahedral easy quantum groups]].+Via [[tannaka_krein_duality|Tannaka-Krein duality]] for compact quantum groups, for every $l\in\N\cup\{\infty\}$ the non-group-theoretical hyperoctahedral category with parameter $l$ corresponds to a family of [[non-group-theoretical_hyperoctahedral_easy_orthogonal_quantum_groups|non-group-theoretical hyperoctahedral easy quantum groups]].
  
 ===== References ===== ===== References =====
non-group-theoretical_hyperoctahedral_categories_of_partitions.1579776996.txt.gz · Last modified: 2021/11/23 11:56 (external edit)