diff -r c2d2a8f8d70c -r a60332c29d0b text/a_inf_blob.tex --- a/text/a_inf_blob.tex Wed Feb 24 01:25:59 2010 +0000 +++ b/text/a_inf_blob.tex Wed Feb 24 06:28:03 2010 +0000 @@ -295,6 +295,29 @@ It is not hard to see that this defines a chain map from $\cB^\cT(M)$ to $C_*(\Maps(M\to T))$. +Next we show that $g$ induces a surjection on homology. +Fix $k > 0$ and choose an open cover $\cU$ of $M$ fine enough so that the union +of any $k$ open sets of $\cU$ is contained in a disjoint union of balls in $M$. +\nn{maybe should refer to elsewhere in this paper where we made a very similar argument} +Let $S_*$ be the subcomplex of $C_*(\Maps(M\to T))$ generated by chains adapted to $\cU$. +It follows from Lemma \ref{extension_lemma_b} that $C_*(\Maps(M\to T))$ +retracts onto $S_*$. + +Let $S_{\le k}$ denote the chains of $S_*$ of degree less than or equal to $k$. +We claim that $S_{\le k}$ lies in the image of $g$. +Let $c$ be a generator of $S_{\le k}$ --- that is, a $j$-parameter family of maps $M\to T$, +$j \le k$. +We chose $\cU$ fine enough so that the support of $c$ is contained in a disjoint union of balls +in $M$. +It follow that we can choose a decomposition $K$ of $M$ so that the support of $c$ is +disjoint from the $n{-}1$-skeleton of $K$. +It is now easy to see that $c$ is in the image of $g$. + +Next we show that $g$ is injective on homology. + + + + \nn{...}