Parabolic Kazhdan-Lusztig polynomial coincide?

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Let $(W,S)$ be a Coxeter system. For any subset $Isubseteq S$, we can have the parabolic Kazhdan-Lusztig polynomial $P_x,w^I(q)$ with respect to $I$.



Now consider $Isubseteq Jsubseteq S$. Both $(W,S)$, $(W_J,J)$ are Coxeter systems.



Since $Isubseteq J$, we get the parabolic Kazhdan-Lusztig polynomial $overlineP_x,w^I(q)$ with respect to $I$ when considering the Coxeter system $(W_J,J)$.



Does $P_x,w^I(q)=overlineP_x,w^I(q)$ for all $x,win W_J$?










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    Let $(W,S)$ be a Coxeter system. For any subset $Isubseteq S$, we can have the parabolic Kazhdan-Lusztig polynomial $P_x,w^I(q)$ with respect to $I$.



    Now consider $Isubseteq Jsubseteq S$. Both $(W,S)$, $(W_J,J)$ are Coxeter systems.



    Since $Isubseteq J$, we get the parabolic Kazhdan-Lusztig polynomial $overlineP_x,w^I(q)$ with respect to $I$ when considering the Coxeter system $(W_J,J)$.



    Does $P_x,w^I(q)=overlineP_x,w^I(q)$ for all $x,win W_J$?










    share|cite|improve this question







    New contributor




    James Cheung is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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      up vote
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      down vote

      favorite









      up vote
      5
      down vote

      favorite











      Let $(W,S)$ be a Coxeter system. For any subset $Isubseteq S$, we can have the parabolic Kazhdan-Lusztig polynomial $P_x,w^I(q)$ with respect to $I$.



      Now consider $Isubseteq Jsubseteq S$. Both $(W,S)$, $(W_J,J)$ are Coxeter systems.



      Since $Isubseteq J$, we get the parabolic Kazhdan-Lusztig polynomial $overlineP_x,w^I(q)$ with respect to $I$ when considering the Coxeter system $(W_J,J)$.



      Does $P_x,w^I(q)=overlineP_x,w^I(q)$ for all $x,win W_J$?










      share|cite|improve this question







      New contributor




      James Cheung is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.











      Let $(W,S)$ be a Coxeter system. For any subset $Isubseteq S$, we can have the parabolic Kazhdan-Lusztig polynomial $P_x,w^I(q)$ with respect to $I$.



      Now consider $Isubseteq Jsubseteq S$. Both $(W,S)$, $(W_J,J)$ are Coxeter systems.



      Since $Isubseteq J$, we get the parabolic Kazhdan-Lusztig polynomial $overlineP_x,w^I(q)$ with respect to $I$ when considering the Coxeter system $(W_J,J)$.



      Does $P_x,w^I(q)=overlineP_x,w^I(q)$ for all $x,win W_J$?







      polynomials coxeter-groups weyl-group kazhdan-lusztig






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      asked Sep 9 at 12:47









      James Cheung

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          Yes, that's true. The standard recursive constructions will give you this fact easily, because the only group elements involved in $P_x,w^I$ are those which are $leq w$ w.r.t. the Bruhat order. If $win W_J$, then all those elements are themselves contained in $W_J$.






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            Yes, that's true. The standard recursive constructions will give you this fact easily, because the only group elements involved in $P_x,w^I$ are those which are $leq w$ w.r.t. the Bruhat order. If $win W_J$, then all those elements are themselves contained in $W_J$.






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              up vote
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              Yes, that's true. The standard recursive constructions will give you this fact easily, because the only group elements involved in $P_x,w^I$ are those which are $leq w$ w.r.t. the Bruhat order. If $win W_J$, then all those elements are themselves contained in $W_J$.






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                up vote
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                up vote
                5
                down vote









                Yes, that's true. The standard recursive constructions will give you this fact easily, because the only group elements involved in $P_x,w^I$ are those which are $leq w$ w.r.t. the Bruhat order. If $win W_J$, then all those elements are themselves contained in $W_J$.






                share|cite|improve this answer












                Yes, that's true. The standard recursive constructions will give you this fact easily, because the only group elements involved in $P_x,w^I$ are those which are $leq w$ w.r.t. the Bruhat order. If $win W_J$, then all those elements are themselves contained in $W_J$.







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                answered Sep 9 at 13:54









                Johannes Hahn

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