# HG changeset patch # User Kevin Walker # Date 1305261754 25200 # Node ID b76b4b79dbe1c808c83ff2c5ef856fd6e8e69341 # Parent c24e59300fcaf9085b5103bcdc255749cd876b9d starting to work on colimit stuff, but not much progress yet diff -r c24e59300fca -r b76b4b79dbe1 blob to-do --- a/blob to-do Tue May 10 14:30:23 2011 -0700 +++ b/blob to-do Thu May 12 21:42:34 2011 -0700 @@ -48,9 +48,6 @@ modules: -* Marked hemispheres, need better language. - - add something like "The is just a ball (\bd N \ N) with its entire boundary (\nd N) marked. We use the term hemisphere because these balls are half the boundary of a larger ball. - * Lemma 6.4.5 needs to actually construct this map! Needs more input! Do we actually need this as written? - KW will look at it; probably needs to be weakened @@ -70,3 +67,5 @@ * lemma [inject 6.3.5?] assumes more splittablity than the axioms imply (?) +* figure for example 3.1.2 (sin 1/z) + diff -r c24e59300fca -r b76b4b79dbe1 text/blobdef.tex --- a/text/blobdef.tex Tue May 10 14:30:23 2011 -0700 +++ b/text/blobdef.tex Thu May 12 21:42:34 2011 -0700 @@ -158,7 +158,7 @@ a manifold. Thus will need to be more careful when speaking of a field $r$ on the complement of the blobs. -\begin{example} +\begin{example} \label{sin1x-example} Consider the four subsets of $\Real^3$, \begin{align*} A & = [0,1] \times [0,1] \times [0,1] \\ diff -r c24e59300fca -r b76b4b79dbe1 text/ncat.tex --- a/text/ncat.tex Tue May 10 14:30:23 2011 -0700 +++ b/text/ncat.tex Thu May 12 21:42:34 2011 -0700 @@ -1037,7 +1037,7 @@ Given permissible decompositions $x = \{X_a\}$ and $y = \{Y_b\}$ of $W$, we say that $x$ is a refinement of $y$, or write $x \le y$, if there is a ball decomposition $\du_a X_a = M_0\to\cdots\to M_m = W$ with $\du_b Y_b = M_i$ for some $i$, -and with $M_0,\ldots, M_i$ each being a disjoint union of balls. +and with $M_0, M_1, \ldots, M_i$ each being a disjoint union of balls. \begin{defn} The poset $\cell(W)$ has objects the permissible decompositions of $W$, @@ -1056,20 +1056,31 @@ An $n$-category $\cC$ determines a functor $\psi_{\cC;W}$ from $\cell(W)$ to the category of sets (possibly with additional structure if $k=n$). -Each $k$-ball $X$ of a decomposition $y$ of $W$ has its boundary decomposed into $k{-}1$-balls, +For pedagogical reasons, let us first the case where a decomposition $y$ of $W$ is a nice, non-pathological +cell decomposition. +Then each $k$-ball $X$ of $y$ has its boundary decomposed into $k{-}1$-balls, and, as described above, we have a subset $\cC(X)\spl \sub \cC(X)$ of morphisms whose boundaries are splittable along this decomposition. -\begin{defn} -Define the functor $\psi_{\cC;W} : \cell(W) \to \Set$ as follows. +We can now +define the functor $\psi_{\cC;W} : \cell(W) \to \Set$ as follows. For a decomposition $x = \bigsqcup_a X_a$ in $\cell(W)$, $\psi_{\cC;W}(x)$ is the subset \begin{equation} -\label{eq:psi-C} +%\label{eq:psi-C} \psi_{\cC;W}(x) \sub \prod_a \cC(X_a)\spl \end{equation} where the restrictions to the various pieces of shared boundaries amongst the cells $X_a$ all agree (this is a fibered product of all the labels of $n$-cells over the labels of $n{-}1$-cells). If $x$ is a refinement of $y$, the map $\psi_{\cC;W}(x) \to \psi_{\cC;W}(y)$ is given by the composition maps of $\cC$. + +In general, $y$ might be more general than a cell decomposition +(see Example \ref{sin1x-example}), so we must define $\psi_{\cC;W}$ in a more roundabout way. +\nn{...} + +\begin{defn} +Define the functor $\psi_{\cC;W} : \cell(W) \to \Set$ as follows. +\nn{...} +If $x$ is a refinement of $y$, the map $\psi_{\cC;W}(x) \to \psi_{\cC;W}(y)$ is given by the composition maps of $\cC$. \end{defn} If $k=n$ in the above definition and we are enriching in some auxiliary category,