text/a_inf_blob.tex
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952:86389e393c17 953:ec1c5ccef482
     4 \label{sec:ainfblob}
     4 \label{sec:ainfblob}
     5 Given an $A_\infty$ $n$-category $\cC$ and an $n$-manifold $M$, we make the following 
     5 Given an $A_\infty$ $n$-category $\cC$ and an $n$-manifold $M$, we make the following 
     6 anticlimactically tautological definition of the blob
     6 anticlimactically tautological definition of the blob
     7 complex.
     7 complex.
     8 \begin{defn}
     8 \begin{defn}
     9 The blob complex
     9 The blob complex $\bc_*(M;\cC)$ of an $n$-manifold $M$ with coefficients in 
    10  $\bc_*(M;\cC)$ of an $n$-manifold $n$ with coefficients in an $A_\infty$ $n$-category is the homotopy colimit $\cl{\cC}(M)$ of \S\ref{ss:ncat_fields}.
    10 an $A_\infty$ $n$-category $\cC$ is the homotopy colimit $\cl{\cC}(M)$ of \S\ref{ss:ncat_fields}.
    11 \end{defn}
    11 \end{defn}
    12 
    12 
    13 We will show below 
    13 We will show below 
    14 in Corollary \ref{cor:new-old}
    14 in Corollary \ref{cor:new-old}
    15 that when $\cC$ is obtained from a system of fields $\cE$ 
    15 that when $\cC$ is obtained from a system of fields $\cE$ 
   385 (It will appear in a future paper.)
   385 (It will appear in a future paper.)
   386 So we content ourselves with
   386 So we content ourselves with
   387 
   387 
   388 \begin{thm}
   388 \begin{thm}
   389 \label{thm:gluing}
   389 \label{thm:gluing}
   390 Suppose $X$ is an $n$-manifold, and $X = X_1\cup (Y\times J) \cup X_2$ (i.e. just as with  $k=n$ above). Then $\bc(X)$ is homotopy equivalent to the $A_\infty$ tensor product $\bc(X_1) \otimes_{\bc(Y), J} \bc(X_2)$.
   390 Suppose $X$ is an $n$-manifold, and $X = X_1\cup (Y\times J) \cup X_2$ (i.e. take $k=n$ in the above discussion). 
       
   391 Then $\bc(X)$ is homotopy equivalent to the $A_\infty$ tensor product $\bc(X_1) \otimes_{\bc(Y), J} \bc(X_2)$.
   391 \end{thm}
   392 \end{thm}
   392 
   393 
   393 \begin{proof}
   394 \begin{proof}
   394 %We will assume $k=n$; the other cases are similar.
   395 %We will assume $k=n$; the other cases are similar.
   395 The proof is similar to that of Theorem \ref{thm:product}.
   396 The proof is similar to that of Theorem \ref{thm:product}.
   413 As in the proof of Theorem \ref{thm:product}, we assign to a generator $a$ of $G_*$
   414 As in the proof of Theorem \ref{thm:product}, we assign to a generator $a$ of $G_*$
   414 an acyclic subcomplex which is (roughly) $\psi\inv(a)$.
   415 an acyclic subcomplex which is (roughly) $\psi\inv(a)$.
   415 The proof of acyclicity is easier in this case since any pair of decompositions of $J$ have
   416 The proof of acyclicity is easier in this case since any pair of decompositions of $J$ have
   416 a common refinement.
   417 a common refinement.
   417 
   418 
   418 The proof that these two maps are inverse to each other is the same as in
   419 The proof that these two maps are homotopy inverse to each other is the same as in
   419 Theorem \ref{thm:product}.
   420 Theorem \ref{thm:product}.
   420 \end{proof}
   421 \end{proof}
   421 
   422 
   422 \medskip
   423 \medskip
   423 
   424