text/ncat.tex
changeset 461 c04bb911d636
parent 456 a5d75e0f9229
child 463 982eca6e2663
equal deleted inserted replaced
458:c675b9a33107 461:c04bb911d636
  1029 Define $\cl{\cC}(W)$ as a vector space via
  1029 Define $\cl{\cC}(W)$ as a vector space via
  1030 \[
  1030 \[
  1031 	\cl{\cC}(W) = \bigoplus_{(x_i)} \psi_{\cC;W}(x_0)[m] ,
  1031 	\cl{\cC}(W) = \bigoplus_{(x_i)} \psi_{\cC;W}(x_0)[m] ,
  1032 \]
  1032 \]
  1033 where the sum is over all $m$-sequences $(x_i)$ and all $m$, and each summand is degree shifted by $m$. 
  1033 where the sum is over all $m$-sequences $(x_i)$ and all $m$, and each summand is degree shifted by $m$. 
       
  1034 Elements of a summand indexed by an $m$-sequences will be call $m$-simplices.
  1034 We endow $\cl{\cC}(W)$ with a differential which is the sum of the differential of the $\psi_{\cC;W}(x_0)$
  1035 We endow $\cl{\cC}(W)$ with a differential which is the sum of the differential of the $\psi_{\cC;W}(x_0)$
  1035 summands plus another term using the differential of the simplicial set of $m$-sequences.
  1036 summands plus another term using the differential of the simplicial set of $m$-sequences.
  1036 More specifically, if $(a, \bar{x})$ denotes an element in the $\bar{x}$
  1037 More specifically, if $(a, \bar{x})$ denotes an element in the $\bar{x}$
  1037 summand of $\cl{\cC}(W)$ (with $\bar{x} = (x_0,\dots,x_k)$), define
  1038 summand of $\cl{\cC}(W)$ (with $\bar{x} = (x_0,\dots,x_k)$), define
  1038 \[
  1039 \[
  1043 %\nn{need to say this better}
  1044 %\nn{need to say this better}
  1044 %\nn{maybe mention that there is a version that emphasizes minimal gluings (antirefinements) which
  1045 %\nn{maybe mention that there is a version that emphasizes minimal gluings (antirefinements) which
  1045 %combine only two balls at a time; for $n=1$ this version will lead to usual definition
  1046 %combine only two balls at a time; for $n=1$ this version will lead to usual definition
  1046 %of $A_\infty$ category}
  1047 %of $A_\infty$ category}
  1047 
  1048 
  1048 We will call $m$ the simplex degree of the complex.
       
  1049 We can think of this construction as starting with a disjoint copy of a complex for each
  1049 We can think of this construction as starting with a disjoint copy of a complex for each
  1050 permissible decomposition (simplex degree 0).
  1050 permissible decomposition (the 0-simplices).
  1051 Then we glue these together with mapping cylinders coming from gluing maps
  1051 Then we glue these together with mapping cylinders coming from gluing maps
  1052 (simplex degree 1).
  1052 (the 1-simplices).
  1053 Then we kill the extra homology we just introduced with mapping 
  1053 Then we kill the extra homology we just introduced with mapping 
  1054 cylinders between the mapping cylinders (simplex degree 2), and so on.
  1054 cylinders between the mapping cylinders (the 2-simplices), and so on.
  1055 
  1055 
  1056 $\cl{\cC}(W)$ is functorial with respect to homeomorphisms of $k$-manifolds. Restricting the $k$-spheres, we have now proved Lemma \ref{lem:spheres}.
  1056 $\cl{\cC}(W)$ is functorial with respect to homeomorphisms of $k$-manifolds. Restricting the $k$-spheres, we have now proved Lemma \ref{lem:spheres}.
  1057 
  1057 
  1058 It is easy to see that
  1058 It is easy to see that
  1059 there are well-defined maps $\cl{\cC}(W)\to\cl{\cC}(\bd W)$, and that these maps
  1059 there are well-defined maps $\cl{\cC}(W)\to\cl{\cC}(\bd W)$, and that these maps