blob1.tex
changeset 5 61751866cf69
parent 4 8599e156a169
child 7 4ef2f77a4652
equal deleted inserted replaced
4:8599e156a169 5:61751866cf69
   588 \section{$n=1$ and Hochschild homology}
   588 \section{$n=1$ and Hochschild homology}
   589 
   589 
   590 In this section we analyze the blob complex in dimension $n=1$
   590 In this section we analyze the blob complex in dimension $n=1$
   591 and find that for $S^1$ the homology of the blob complex is the 
   591 and find that for $S^1$ the homology of the blob complex is the 
   592 Hochschild homology of the category (algebroid) that we started with.
   592 Hochschild homology of the category (algebroid) that we started with.
       
   593 \nn{or maybe say here that the complexes are quasi-isomorphic?  in general,
       
   594 should perhaps put more emphasis on the complexes and less on the homology.}
   593 
   595 
   594 Notation: $HB_i(X) = H_i(\bc_*(X))$.
   596 Notation: $HB_i(X) = H_i(\bc_*(X))$.
   595 
   597 
   596 Let us first note that there is no loss of generality in assuming that our system of 
   598 Let us first note that there is no loss of generality in assuming that our system of 
   597 fields comes from a category.
   599 fields comes from a category.
   626 of $R$, each labeled by a morphism of $C$.
   628 of $R$, each labeled by a morphism of $C$.
   627 The intervals between the points are labeled by objects of $C$, consistent with
   629 The intervals between the points are labeled by objects of $C$, consistent with
   628 the boundary condition $c$ and the domains and ranges of the point labels.
   630 the boundary condition $c$ and the domains and ranges of the point labels.
   629 \item There is an evaluation map $e: \cC(I; a, b) \to \mor(a, b)$ given by
   631 \item There is an evaluation map $e: \cC(I; a, b) \to \mor(a, b)$ given by
   630 composing the morphism labels of the points.
   632 composing the morphism labels of the points.
       
   633 Note that we also need the * of *-1-category here in order to make all the morphisms point
       
   634 the same way.
   631 \item For $x \in \mor(a, b)$ let $\chi(x) \in \cC(I; a, b)$ be the field with a single
   635 \item For $x \in \mor(a, b)$ let $\chi(x) \in \cC(I; a, b)$ be the field with a single
   632 point (at some standard location) labeled by $x$.
   636 point (at some standard location) labeled by $x$.
   633 Then the kernel of the evaluation map $U(I; a, b)$ is generated by things of the 
   637 Then the kernel of the evaluation map $U(I; a, b)$ is generated by things of the 
   634 form $y - \chi(e(y))$.
   638 form $y - \chi(e(y))$.
   635 Thus we can, if we choose, restrict the blob twig labels to things of this form.
   639 Thus we can, if we choose, restrict the blob twig labels to things of this form.