text/evmap.tex
changeset 88 014a16e6e55c
parent 87 af6b7205560c
child 89 6c7662fcddc5
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   162 Choose a metric on $X$.
   162 Choose a metric on $X$.
   163 Choose a monotone decreasing sequence of positive real numbers $\ep_i$ converging to zero
   163 Choose a monotone decreasing sequence of positive real numbers $\ep_i$ converging to zero
   164 (e.g.\ $\ep_i = 2^{-i}$).
   164 (e.g.\ $\ep_i = 2^{-i}$).
   165 Choose another sequence of positive real numbers $\delta_i$ such that $\delta_i/\ep_i$
   165 Choose another sequence of positive real numbers $\delta_i$ such that $\delta_i/\ep_i$
   166 converges monotonically to zero (e.g.\ $\delta_i = \ep_i^2$).
   166 converges monotonically to zero (e.g.\ $\delta_i = \ep_i^2$).
   167 Given a generator $p\otimes b$ of $CD_*(X)\otimes \bc_*(X)$ and non-negative integers $i$ and $k$
   167 Let $\phi_l$ be an increasing sequence of positive numbers
       
   168 satisfying the inequalities of Lemma \ref{xx2phi} (e.g. $\phi_l = 2^{3^{l-1}}$).
       
   169 Given a generator $p\otimes b$ of $CD_*(X)\otimes \bc_*(X)$ and non-negative integers $i$ and $l$
   168 define
   170 define
   169 \[
   171 \[
   170 	N_{i,k}(p\ot b) \deq \Nbd_{k\ep_i}(|b|) \cup \Nbd_{4^k\delta_i}(|p|).
   172 	N_{i,l}(p\ot b) \deq \Nbd_{l\ep_i}(|b|) \cup \Nbd_{\phi_l\delta_i}(|p|).
   171 \]
   173 \]
   172 \nn{not currently correct; maybe need to split $k$ into two parameters}
       
   173 In other words, we use the metric to choose nested neighborhoods of $|b|\cup |p|$ (parameterized
   174 In other words, we use the metric to choose nested neighborhoods of $|b|\cup |p|$ (parameterized
   174 by $k$), with $\ep_i$ controlling the size of the buffer around $|b|$ and $\delta_i$ controlling
   175 by $l$), with $\ep_i$ controlling the size of the buffers around $|b|$ and $\delta_i$ controlling
   175 the size of the buffer around $|p|$.
   176 the size of the buffers around $|p|$.
   176 (The $4^k$ comes from Lemma \ref{xxxx}.)
       
   177 
   177 
   178 Next we define subcomplexes $G_*^{i,m} \sub CD_*(X)\otimes \bc_*(X)$.
   178 Next we define subcomplexes $G_*^{i,m} \sub CD_*(X)\otimes \bc_*(X)$.
   179 Let $p\ot b$ be a generator of $CD_*(X)\otimes \bc_*(X)$ and let $k = \deg(p\ot b)
   179 Let $p\ot b$ be a generator of $CD_*(X)\otimes \bc_*(X)$ and let $k = \deg(p\ot b)
   180 = \deg(p) + \deg(b)$.
   180 = \deg(p) + \deg(b)$.
   181 $p\ot b$ is (by definition) in $G_*^{i,m}$ if either (a) $\deg(p) = 0$ or (b)
   181 $p\ot b$ is (by definition) in $G_*^{i,m}$ if either (a) $\deg(p) = 0$ or (b)
   213 \]
   213 \]
   214 Let $\bd(p\ot b) = \sum_j p_j\ot b_j$, and let $V^j$ be the choice of neighborhood
   214 Let $\bd(p\ot b) = \sum_j p_j\ot b_j$, and let $V^j$ be the choice of neighborhood
   215 of $|p_j|\cup |b_j|$ made at the preceding stage of the induction.
   215 of $|p_j|\cup |b_j|$ made at the preceding stage of the induction.
   216 For all $j$, 
   216 For all $j$, 
   217 \[
   217 \[
   218 	V^j \subeq N_{i,(k-1)+1}(p_j\ot b_j) \subeq N_{i,k}(p\ot b) \subeq V .
   218 	V^j \subeq N_{i,k}(p_j\ot b_j) \subeq N_{i,k}(p\ot b) \subeq V .
   219 \]
   219 \]
   220 (The second inclusion uses the facts that $|p_j| \subeq |p|$ and $|b_j| \subeq |b|$.)
   220 (The second inclusion uses the facts that $|p_j| \subeq |p|$ and $|b_j| \subeq |b|$.)
   221 We therefore have splittings
   221 We therefore have splittings
   222 \[
   222 \[
   223 	p = p'\bullet p'' , \;\; b = b'\bullet b'' , \;\; e(\bd(p\ot b)) = f'\bullet b'' ,
   223 	p = p'\bullet p'' , \;\; b = b'\bullet b'' , \;\; e(\bd(p\ot b)) = f'\bullet b'' ,
   229 near $\bd V$, the expressions $p(V) \sub X$ and $p(X\setmin V) \sub X$ are
   229 near $\bd V$, the expressions $p(V) \sub X$ and $p(X\setmin V) \sub X$ are
   230 unambiguous.)
   230 unambiguous.)
   231 We have $\deg(p'') = 0$ and, inductively, $f'' = p''(b'')$.
   231 We have $\deg(p'') = 0$ and, inductively, $f'' = p''(b'')$.
   232 %We also have that $\deg(b'') = 0 = \deg(p'')$.
   232 %We also have that $\deg(b'') = 0 = \deg(p'')$.
   233 Choose $x' \in \bc_*(p(V))$ such that $\bd x' = f'$.
   233 Choose $x' \in \bc_*(p(V))$ such that $\bd x' = f'$.
   234 This is possible by \nn{...}.
   234 This is possible by \ref{bcontract}, \ref{disjunion} and \nn{prop. 2 of local relations (isotopy)}.
   235 Finally, define
   235 Finally, define
   236 \[
   236 \[
   237 	e(p\ot b) \deq x' \bullet p''(b'') .
   237 	e(p\ot b) \deq x' \bullet p''(b'') .
   238 \]
   238 \]
   239 
   239 
   241 For each generator $p\ot b$ we specify the acyclic (in positive degrees) 
   241 For each generator $p\ot b$ we specify the acyclic (in positive degrees) 
   242 target complex $\bc_*(p(V)) \bullet p''(b'')$.
   242 target complex $\bc_*(p(V)) \bullet p''(b'')$.
   243 
   243 
   244 The definition of $e: G_*^{i,m} \to \bc_*(X)$ depends on two sets of choices:
   244 The definition of $e: G_*^{i,m} \to \bc_*(X)$ depends on two sets of choices:
   245 The choice of neighborhoods $V$ and the choice of inverse boundaries $x'$.
   245 The choice of neighborhoods $V$ and the choice of inverse boundaries $x'$.
   246 The next two lemmas show that up to (iterated) homotopy $e$ is independent
   246 The next lemma shows that up to (iterated) homotopy $e$ is independent
   247 of these choices.
   247 of these choices.
   248 
   248 (Note that independence of choices of $x'$ (for fixed choices of $V$)
   249 \begin{lemma}
   249 is a standard result in the method of acyclic models.)
   250 Let $\tilde{e} :  G_*^{i,m} \to \bc_*(X)$ be a chain map constructed like $e$ above, but with
   250 
   251 different choices of $x'$ at each step.
   251 %\begin{lemma}
   252 (Same choice of $V$ at each step.)
   252 %Let $\tilde{e} :  G_*^{i,m} \to \bc_*(X)$ be a chain map constructed like $e$ above, but with
   253 Then $e$ and $\tilde{e}$ are homotopic via a homotopy in $\bc_*(p(V)) \bullet p''(b'')$.
   253 %different choices of $x'$ at each step.
   254 Any two choices of such a first-order homotopy are second-order homotopic, and so on, 
   254 %(Same choice of $V$ at each step.)
   255 to arbitrary order.
   255 %Then $e$ and $\tilde{e}$ are homotopic via a homotopy in $\bc_*(p(V)) \bullet p''(b'')$.
   256 \end{lemma}
   256 %Any two choices of such a first-order homotopy are second-order homotopic, and so on, 
   257 
   257 %to arbitrary order.
   258 \begin{proof}
   258 %\end{lemma}
   259 This is a standard result in the method of acyclic models.
   259 
   260 \nn{should we say more here?}
   260 %\begin{proof}
   261 \nn{maybe this lemma should be subsumed into the next lemma.  probably it should.}
   261 %This is a standard result in the method of acyclic models.
   262 \end{proof}
   262 %\nn{should we say more here?}
       
   263 %\nn{maybe this lemma should be subsumed into the next lemma.  probably it should.}
       
   264 %\end{proof}
   263 
   265 
   264 \begin{lemma} \label{m_order_hty}
   266 \begin{lemma} \label{m_order_hty}
   265 Let $\tilde{e} :  G_*^{i,m} \to \bc_*(X)$ be a chain map constructed like $e$ above, but with
   267 Let $\tilde{e} :  G_*^{i,m} \to \bc_*(X)$ be a chain map constructed like $e$ above, but with
   266 different choices of $V$ (and hence also different choices of $x'$) at each step.
   268 different choices of $V$ (and hence also different choices of $x'$) at each step.
   267 If $m \ge 1$ then $e$ and $\tilde{e}$ are homotopic.
   269 If $m \ge 1$ then $e$ and $\tilde{e}$ are homotopic.
   286 			\;\; e(p\ot b) - \tilde{e}(p\ot b) - h(\bd(p\ot b)) = f'_1\bullet f''_1 ,
   288 			\;\; e(p\ot b) - \tilde{e}(p\ot b) - h(\bd(p\ot b)) = f'_1\bullet f''_1 ,
   287 \]
   289 \]
   288 where $p'_1 \in CD_*(V_1)$, $p''_1 \in CD_*(X\setmin V_1)$, 
   290 where $p'_1 \in CD_*(V_1)$, $p''_1 \in CD_*(X\setmin V_1)$, 
   289 $b'_1 \in \bc_*(V_1)$, $b''_1 \in \bc_*(X\setmin V_1)$, 
   291 $b'_1 \in \bc_*(V_1)$, $b''_1 \in \bc_*(X\setmin V_1)$, 
   290 $f'_1 \in \bc_*(p(V_1))$, and $f''_1 \in \bc_*(p(X\setmin V_1))$.
   292 $f'_1 \in \bc_*(p(V_1))$, and $f''_1 \in \bc_*(p(X\setmin V_1))$.
   291 Inductively, $\bd f'_1 = 0$.
   293 Inductively, $\bd f'_1 = 0$ and $f_1'' = p_1''(b_1'')$.
   292 Choose $x'_1 \in \bc_*(p(V_1))$ so that $\bd x'_1 = f'_1$.
   294 Choose $x'_1 \in \bc_*(p(V_1))$ so that $\bd x'_1 = f'_1$.
   293 Define 
   295 Define 
   294 \[
   296 \[
   295 	h(p\ot b) \deq x'_1 \bullet p''_1(b''_1) .
   297 	h(p\ot b) \deq x'_1 \bullet p''_1(b''_1) .
   296 \]
   298 \]
   316 	g_j \deq h_j\circ h_{j-1} \circ \cdots \circ h_1 .
   318 	g_j \deq h_j\circ h_{j-1} \circ \cdots \circ h_1 .
   317 \]
   319 \]
   318 The next lemma says that for all generators $p\ot b$ we can choose $j$ large enough so that
   320 The next lemma says that for all generators $p\ot b$ we can choose $j$ large enough so that
   319 $g_j(p)\ot b$ lies in $G_*^{i,m}$, for arbitrary $m$ and sufficiently large $i$ 
   321 $g_j(p)\ot b$ lies in $G_*^{i,m}$, for arbitrary $m$ and sufficiently large $i$ 
   320 (depending on $b$, $n = \deg(p)$ and $m$).
   322 (depending on $b$, $n = \deg(p)$ and $m$).
   321 \nn{not the same $n$ as the dimension of the manifolds; fix this}
   323 (Note: Don't confuse this $n$ with the top dimension $n$ used elsewhere in this paper.)
   322 
   324 
   323 \begin{lemma} \label{Gim_approx}
   325 \begin{lemma} \label{Gim_approx}
   324 Fix a blob diagram $b$, a homotopy order $m$ and a degree $n$ for $CD_*(X)$.
   326 Fix a blob diagram $b$, a homotopy order $m$ and a degree $n$ for $CD_*(X)$.
   325 Then there exists a constant $k_{bmn}$ such that for all $i \ge k_{bmn}$
   327 Then there exists a constant $k_{bmn}$ such that for all $i \ge k_{bmn}$
   326 there exists another constant $j_i$ such that for all $j \ge j_i$ and all $p\in CD_n(X)$ 
   328 there exists another constant $j_i$ such that for all $j \ge j_i$ and all $p\in CD_n(X)$ 
   343 \[
   345 \[
   344 	t\ep_k < l
   346 	t\ep_k < l
   345 \]
   347 \]
   346 and
   348 and
   347 \[
   349 \[
   348 	n\cdot ( 4^t \delta_i) < \ep_k/3 .
   350 	n\cdot ( \phi_t \delta_i) < \ep_k/3 .
   349 \]
   351 \]
   350 Let $i \ge k_{bmn}$.
   352 Let $i \ge k_{bmn}$.
   351 Choose $j = j_i$ so that
   353 Choose $j = j_i$ so that
   352 \[
   354 \[
   353 	t\gamma_j < \ep_i/3
   355 	t\gamma_j < \ep_i/3