text/hochschild.tex
changeset 961 c57afb230bb1
parent 940 04079a7aeaef
equal deleted inserted replaced
960:bc4086c639b6 961:c57afb230bb1
   216 Let $b$ be a blob diagram in $F_*^\ep$.
   216 Let $b$ be a blob diagram in $F_*^\ep$.
   217 Define $f(b)$ to be the result of moving any blob boundary points which lie on *
   217 Define $f(b)$ to be the result of moving any blob boundary points which lie on *
   218 to distance $\ep$ from *.
   218 to distance $\ep$ from *.
   219 (Move right or left so as to shrink the blob.)
   219 (Move right or left so as to shrink the blob.)
   220 Extend to get a chain map $f: F_*^\ep \to F_*^\ep$.
   220 Extend to get a chain map $f: F_*^\ep \to F_*^\ep$.
   221 By Lemma \ref{support-shrink}, $f$ is homotopic to the identity.
   221 By Corollary \ref{disj-union-contract}, 
       
   222 $f$ is homotopic to the identity.
       
   223 (Use the facts that $f$ factors though a map from a disjoint union of balls
       
   224 into $S^1$, and that $f$ is the identity in degree 0.)
   222 Since the image of $f$ is in $J_*$, and since any blob chain is in $F_*^\ep$
   225 Since the image of $f$ is in $J_*$, and since any blob chain is in $F_*^\ep$
   223 for $\ep$ sufficiently small, we have that $J_*$ is homotopic to all of $\bc_*(S^1)$.
   226 for $\ep$ sufficiently small, we have that $J_*$ is homotopic to all of $\bc_*(S^1)$.
   224 
   227 
   225 We now define a homotopy inverse $s: J_* \to K_*(C)$ to the inclusion $i$.
   228 We now define a homotopy inverse $s: J_* \to K_*(C)$ to the inclusion $i$.
   226 If $y$ is a field defined on a neighborhood of *, define $s(y) = y$ if
   229 If $y$ is a field defined on a neighborhood of *, define $s(y) = y$ if