text/hochschild.tex
changeset 286 ff867bfc8e9c
parent 257 ae5a542c958e
child 314 6e23226d1cca
equal deleted inserted replaced
282:7afacaa87bdb 286:ff867bfc8e9c
   174 \ref{lem:module-blob},
   174 \ref{lem:module-blob},
   175 \ref{lem:hochschild-exact}, \ref{lem:hochschild-coinvariants} and
   175 \ref{lem:hochschild-exact}, \ref{lem:hochschild-coinvariants} and
   176 \ref{lem:hochschild-free}.
   176 \ref{lem:hochschild-free}.
   177 \end{proof}
   177 \end{proof}
   178 
   178 
       
   179 \subsection{Technical details}
   179 \begin{proof}[Proof of Lemma \ref{lem:module-blob}]
   180 \begin{proof}[Proof of Lemma \ref{lem:module-blob}]
   180 We show that $K_*(C)$ is quasi-isomorphic to $\bc_*(S^1)$.
   181 We show that $K_*(C)$ is quasi-isomorphic to $\bc_*(S^1)$.
   181 $K_*(C)$ differs from $\bc_*(S^1)$ only in that the base point *
   182 $K_*(C)$ differs from $\bc_*(S^1)$ only in that the base point *
   182 is always a labeled point in $K_*(C)$, while in $\bc_*(S^1)$ it may or may not be.
   183 is always a labeled point in $K_*(C)$, while in $\bc_*(S^1)$ it may or may not be.
   183 In particular, there is an inclusion map $i: K_*(C) \to \bc_*(S^1)$.
   184 In particular, there is an inclusion map $i: K_*(C) \to \bc_*(S^1)$.
   466 This allows us to construct $x\in K''_1$ such that $\bd x = y$.
   467 This allows us to construct $x\in K''_1$ such that $\bd x = y$.
   467 (The label of $B$ is the restriction of $y$ to $B$.)
   468 (The label of $B$ is the restriction of $y$ to $B$.)
   468 It follows that $H_0(K''_*) \cong C$.
   469 It follows that $H_0(K''_*) \cong C$.
   469 \end{proof}
   470 \end{proof}
   470 
   471 
   471 \medskip
   472 \subsection{An explicit chain map in low degrees}
   472 
   473 
   473 For purposes of illustration, we describe an explicit chain map
   474 For purposes of illustration, we describe an explicit chain map
   474 $\HC_*(M) \to K_*(M)$
   475 $\HC_*(M) \to K_*(M)$
   475 between the Hochschild complex and the blob complex (with bimodule point)
   476 between the Hochschild complex and the blob complex (with bimodule point)
   476 for degree $\le 2$.
   477 for degree $\le 2$.