# HG changeset patch # User Kevin Walker # Date 1284963321 25200 # Node ID 0bc6fa29b62ab7fdaaa143ce58dd57e307f76a4a # Parent 4f142fcd386e1c81aa52e029f2d36b255df785aa# Parent 3baa4e4d395e4434da0acd328e480ecbfbf7479f Automated merge with https://tqft.net/hg/blob/ diff -r 4f142fcd386e -r 0bc6fa29b62a text/blobdef.tex --- a/text/blobdef.tex Sun Sep 19 23:11:59 2010 -0500 +++ b/text/blobdef.tex Sun Sep 19 23:15:21 2010 -0700 @@ -260,5 +260,8 @@ (When the fields come from an $n$-category, this correspondence works best if we think of each twig label $u_i$ as having the form $x - s(e(x))$, where $x$ is an arbitrary field on $B_i$, $e: \cF(B_i) \to C$ is the evaluation map, and $s:C \to \cF(B_i)$ is some fixed section of $e$.) + +For lack of a better name, we'll call elements of $P$ cone-product polyhedra, +and say that blob diagrams have the structure of a cone-product set (analogous to simplicial set). \end{remark} diff -r 4f142fcd386e -r 0bc6fa29b62a text/ncat.tex --- a/text/ncat.tex Sun Sep 19 23:11:59 2010 -0500 +++ b/text/ncat.tex Sun Sep 19 23:15:21 2010 -0700 @@ -1034,6 +1034,14 @@ In the $A_\infty$ case, enriched over chain complexes, the concrete description of the homotopy colimit is more involved. +We will describe two different (but homotopy equivalent) versions of the homotopy colimit of $\psi_{\cC;W}$. +The first is the usual one, which works for any indexing category. +The second construction, we we call the {\it local} homotopy colimit, +\nn{give it a different name?} +is more closely related to the blob complex +construction of \S \ref{sec:blob-definition} and takes advantage of local (gluing) properties +of the indexing category $\cell(W)$. + Define an $m$-sequence in $W$ to be a sequence $x_0 \le x_1 \le \dots \le x_m$ of permissible decompositions of $W$. Such sequences (for all $m$) form a simplicial set in $\cell(W)$. Define $\cl{\cC}(W)$ as a vector space via @@ -1051,7 +1059,6 @@ \] where $d_j(\bar{x}) = (x_0,\dots,x_{j-1},x_{j+1},\dots,x_k)$ and $g: \psi_\cC(x_0)\to \psi_\cC(x_1)$ is the usual gluing map coming from the antirefinement $x_0 \le x_1$. -%\nn{need to say this better} %\nn{maybe mention that there is a version that emphasizes minimal gluings (antirefinements) which %combine only two balls at a time; for $n=1$ this version will lead to usual definition %of $A_\infty$ category} @@ -1063,6 +1070,24 @@ Then we kill the extra homology we just introduced with mapping cylinders between the mapping cylinders (the 2-simplices), and so on. +Next we describe the local homotopy colimit. +This is similar to the usual homotopy colimit, but using +a cone-product set (Remark \ref{blobsset-remark}) in place of a simplicial set. +The cone-product $m$-polyhedra for the set are pairs $(x, E)$, where $x$ is a decomposition of $W$ +and $E$ is an $m$-blob diagram such that each blob is a union of balls of $x$. +(Recall that this means that the interiors of +each pair of blobs (i.e.\ balls) of $E$ are either disjoint or nested.) +To each $(x, E)$ we associate the chain complex $\psi_{\cC;W}(x)$, shifted in degree by $m$. +The boundary has a term for omitting each blob of $E$. +If we omit an innermost blob then we replace $x$ by the formal difference $x - \gl(x)$, where +$\gl(x)$ is obtained from $x$ by gluing together the balls of $x$ contained in the blob we are omitting. +The gluing maps of $\cC$ give us a maps from $\psi_{\cC;W}(x)$ to $\psi_{\cC;W}(\gl(x))$. + +One can show that the usual hocolimit and the local hocolimit are homotopy equivalent using an +Eilenberg-Zilber type subdivision argument. + +\medskip + $\cl{\cC}(W)$ is functorial with respect to homeomorphisms of $k$-manifolds. Restricting the $k$-spheres, we have now proved Lemma \ref{lem:spheres}. It is easy to see that