diff -r cf01e213044a -r 7537032ad5a0 text/appendixes/famodiff.tex --- a/text/appendixes/famodiff.tex Tue Apr 06 08:43:37 2010 -0700 +++ b/text/appendixes/famodiff.tex Tue Apr 06 13:27:45 2010 -0700 @@ -2,6 +2,63 @@ \section{Families of Diffeomorphisms} \label{sec:localising} + +\medskip +\hrule +\medskip +\nn{the following was removed from earlier section; it should be reincorporated somehwere +in this section} + +Let $\cU = \{U_\alpha\}$ be an open cover of $X$. +A $k$-parameter family of homeomorphisms $f: P \times X \to X$ is +{\it adapted to $\cU$} if there is a factorization +\eq{ + P = P_1 \times \cdots \times P_m +} +(for some $m \le k$) +and families of homeomorphisms +\eq{ + f_i : P_i \times X \to X +} +such that +\begin{itemize} +\item each $f_i$ is supported on some connected $V_i \sub X$; +\item the sets $V_i$ are mutually disjoint; +\item each $V_i$ is the union of at most $k_i$ of the $U_\alpha$'s, +where $k_i = \dim(P_i)$; and +\item $f(p, \cdot) = g \circ f_1(p_1, \cdot) \circ \cdots \circ f_m(p_m, \cdot)$ +for all $p = (p_1, \ldots, p_m)$, for some fixed $g \in \Homeo(X)$. +\end{itemize} +A chain $x \in CH_k(X)$ is (by definition) adapted to $\cU$ if it is the sum +of singular cells, each of which is adapted to $\cU$. +\medskip +\hrule +\medskip +\nn{another refugee:} + +We will actually prove the following more general result. +Let $S$ and $T$ be an arbitrary topological spaces. +%\nn{might need to restrict $S$; the proof uses partition of unity on $S$; +%check this; or maybe just restrict the cover} +Let $CM_*(S, T)$ denote the singular chains on the space of continuous maps +from $S$ to $T$. +Let $\cU$ be an open cover of $S$ which affords a partition of unity. +\nn{for some $S$ and $\cU$ there is no partition of unity? like if $S$ is not paracompact? +in any case, in our applications $S$ will always be a manifold} + +\begin{lemma} \label{extension_lemma_b} +Let $x \in CM_k(S, T)$ be a singular chain such that $\bd x$ is adapted to $\cU$. +Then $x$ is homotopic (rel boundary) to some $x' \in CM_k(S, T)$ which is adapted to $\cU$. +Furthermore, one can choose the homotopy so that its support is equal to the support of $x$. +If $S$ and $T$ are manifolds, the statement remains true if we replace $CM_*(S, T)$ with +chains of smooth maps or immersions. +\end{lemma} + +\medskip +\hrule +\medskip + + In this appendix we provide the proof of \nn{should change this to the more general \ref{extension_lemma_b}}