...
--- a/text/ncat.tex Sun Jan 10 18:27:49 2010 +0000
+++ b/text/ncat.tex Sun Jan 10 20:48:09 2010 +0000
@@ -673,8 +673,6 @@
$a\in \psi_{\cC;W,c}(x)$ for some decomposition $x$, and $g: \psi_{\cC;W,c}(x)
\to \psi_{\cC;W,c}(y)$ is value of $\psi_{\cC;W,c}$ on some antirefinement $x \leq y$.
-\nn{ ** resume revising here}
-
In the $A_\infty$ case enriched over chain complexes, the concrete description of the homotopy colimit
is more involved.
%\nn{should probably rewrite this to be compatible with some standard reference}
@@ -684,7 +682,7 @@
\[
V = \bigoplus_{(x_i)} \psi_{\cC;W}(x_0)[m] ,
\]
-where the sum is over all $m$-sequences $(x_i)$ and all $m$, and each summand is degree shifted by $m$. (Our homological conventions are obtuse: if a complex $U$ is concentrated in degree $0$, the complex $U[m]$ is concentrated in degree $m$.)
+where the sum is over all $m$-sequences $(x_i)$ and all $m$, and each summand is degree shifted by $m$. (Our homological conventions are non-standard: if a complex $U$ is concentrated in degree $0$, the complex $U[m]$ is concentrated in degree $m$.)
We endow $V$ with a differential which is the sum of the differential of the $\psi_{\cC;W}(x_0)$
summands plus another term using the differential of the simplicial set of $m$-sequences.
More specifically, if $(a, \bar{x})$ denotes an element in the $\bar{x}$
@@ -693,7 +691,7 @@
\bd (a, \bar{x}) = (\bd a, \bar{x}) + (-1)^{\deg{a}} (g(a), d_0(\bar{x})) + (-1)^{\deg{a}} \sum_{j=1}^k (-1)^{j} (a, d_j(\bar{x})) ,
\]
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 $x_0 < x_1$.
+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
@@ -704,7 +702,7 @@
permissible decomposition (filtration degree 0).
Then we glue these together with mapping cylinders coming from gluing maps
(filtration degree 1).
-Then we kill the extra homology we just introduced with mapping cylinder between the mapping cylinders (filtration degree 2).
+Then we kill the extra homology we just introduced with mapping cylinders between the mapping cylinders (filtration degree 2).
And so on.
$\cC(W)$ is functorial with respect to homeomorphisms of $k$-manifolds.
@@ -726,7 +724,9 @@
a.k.a.\ actions).
The definition will be very similar to that of $n$-categories.
\nn{** need to make sure all revisions of $n$-cat def are also made to module def.}
-\nn{should they be called $n$-modules instead of just modules? probably not, but worth considering.}
+%\nn{should they be called $n$-modules instead of just modules? probably not, but worth considering.}
+
+\nn{** resume revising here}
Our motivating example comes from an $(m{-}n{+}1)$-dimensional manifold $W$ with boundary
in the context of an $m{+}1$-dimensional TQFT.