diff -r 1acb5f508cf6 -r 7e9a7b9605d3 text/hochschild.tex --- a/text/hochschild.tex Fri Mar 05 20:27:08 2010 +0000 +++ b/text/hochschild.tex Thu Mar 11 23:20:25 2010 +0000 @@ -182,14 +182,27 @@ is always a labeled point in $K_*(C)$, while in $\bc_*(S^1)$ it may or may not be. In particular, there is an inclusion map $i: K_*(C) \to \bc_*(S^1)$. -We define a left inverse $s: \bc_*(S^1) \to K_*(C)$ to the inclusion as follows. +We want to define a homotopy inverse to the above inclusion, but before doing so +we must replace $\bc_*(S^1)$ with a homotopy equivalent subcomplex. +Let $J_* \sub \bc_*(S^1)$ be the subcomplex where * does not lie to the boundary +of any blob. Note that the image of $i$ is contained in $J_*$. +Note also that in $\bc_*(S^1)$ (away from $J_*$) +a blob diagram could have multiple (nested) blobs whose +boundaries contain *, on both the right and left of *. + +We claim that $J_*$ is homotopy equivalent to $\bc_*(S^1)$. +Let $F_*^\ep \sub \bc_*(S^1)$ be the subcomplex where there there are no labeled +points within distance $\ep$ of * on the right. +(This includes * itself.) +\nn{...} + + + +We want to define a homotopy inverse $s: \bc_*(S^1) \to K_*(C)$ to the inclusion. If $y$ is a field defined on a neighborhood of *, define $s(y) = y$ if * is a labeled point in $y$. Otherwise, define $s(y)$ to be the result of adding a label 1 (identity morphism) at *. Extending linearly, we get the desired map $s: \bc_*(S^1) \to K_*(C)$. -%Let $x \in \bc_*(S^1)$. -%Let $s(x)$ be the result of replacing each field $y$ (containing *) mentioned in -%$x$ with $s(y)$. It is easy to check that $s$ is a chain map and $s \circ i = \id$. Let $N_\ep$ denote the ball of radius $\ep$ around *.