What is the intersection of the vertices of a face of a simplicial complex?












2












$begingroup$


I am currently reading "Subgroup graph methods for presentations of finitely generated groups and the contractibility of associated simplicial complexes" By Cora Welsch and I'm a bit stuck with Theorem 5.6.



She considers a subcomplex $U$ of the nerve complex $NC(G,H_{fi})$.




I dont understand why:




  1. There always exists a finite set $Sigma$ consisting of all maximal simplices of $U$?

  2. What is the intersection of the vertices of an element $ sigma in Sigma $? (She denotes it by $cap sigma$.)




Thanks in advance!










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$endgroup$

















    2












    $begingroup$


    I am currently reading "Subgroup graph methods for presentations of finitely generated groups and the contractibility of associated simplicial complexes" By Cora Welsch and I'm a bit stuck with Theorem 5.6.



    She considers a subcomplex $U$ of the nerve complex $NC(G,H_{fi})$.




    I dont understand why:




    1. There always exists a finite set $Sigma$ consisting of all maximal simplices of $U$?

    2. What is the intersection of the vertices of an element $ sigma in Sigma $? (She denotes it by $cap sigma$.)




    Thanks in advance!










    share|cite|improve this question











    $endgroup$















      2












      2








      2





      $begingroup$


      I am currently reading "Subgroup graph methods for presentations of finitely generated groups and the contractibility of associated simplicial complexes" By Cora Welsch and I'm a bit stuck with Theorem 5.6.



      She considers a subcomplex $U$ of the nerve complex $NC(G,H_{fi})$.




      I dont understand why:




      1. There always exists a finite set $Sigma$ consisting of all maximal simplices of $U$?

      2. What is the intersection of the vertices of an element $ sigma in Sigma $? (She denotes it by $cap sigma$.)




      Thanks in advance!










      share|cite|improve this question











      $endgroup$




      I am currently reading "Subgroup graph methods for presentations of finitely generated groups and the contractibility of associated simplicial complexes" By Cora Welsch and I'm a bit stuck with Theorem 5.6.



      She considers a subcomplex $U$ of the nerve complex $NC(G,H_{fi})$.




      I dont understand why:




      1. There always exists a finite set $Sigma$ consisting of all maximal simplices of $U$?

      2. What is the intersection of the vertices of an element $ sigma in Sigma $? (She denotes it by $cap sigma$.)




      Thanks in advance!







      group-theory group-presentation simplicial-complex






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      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Dec 3 '18 at 1:15









      Shaun

      9,246113684




      9,246113684










      asked Jan 13 '18 at 14:09









      Lau_GrvLau_Grv

      111




      111






















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