diff -r 7cb7de37cbf9 -r 121c580d5ef7 text/ncat.tex --- a/text/ncat.tex Tue Jun 01 21:44:09 2010 -0700 +++ b/text/ncat.tex Tue Jun 01 23:07:42 2010 -0700 @@ -74,7 +74,7 @@ We will concentrate on the case of PL unoriented manifolds. (The ambitious reader may want to keep in mind two other classes of balls. -The first is balls equipped with a map to some other space $Y$. \todo{cite something of Teichner's?} +The first is balls equipped with a map to some other space $Y$ (c.f. \cite{MR2079378}). This will be used below to describe the blob complex of a fiber bundle with base space $Y$. The second is balls equipped with a section of the the tangent bundle, or the frame @@ -86,7 +86,7 @@ of morphisms). The 0-sphere is unusual among spheres in that it is disconnected. Correspondingly, for 1-morphisms it makes sense to distinguish between domain and range. -(Actually, this is only true in the oriented case, with 1-morphsims parameterized +(Actually, this is only true in the oriented case, with 1-morphisms parameterized by oriented 1-balls.) For $k>1$ and in the presence of strong duality the division into domain and range makes less sense. For example, in a pivotal tensor category, there are natural isomorphisms $\Hom{}{A}{B \tensor C} \isoto \Hom{}{B^* \tensor A}{C}$, etc. (sometimes called ``Frobenius reciprocity''), which canonically identify all the morphism spaces which have the same boundary. We prefer to not make the distinction in the first place. @@ -123,7 +123,7 @@ Most of the examples of $n$-categories we are interested in are enriched in the following sense. The various sets of $n$-morphisms $\cC(X; c)$, for all $n$-balls $X$ and -all $c\in \cC(\bd X)$, have the structure of an object in some auxiliary category +all $c\in \cC(\bd X)$, have the structure of an object in some auxiliary symmetric monoidal category (e.g.\ vector spaces, or modules over some ring, or chain complexes), and all the structure maps of the $n$-category should be compatible with the auxiliary category structure. @@ -142,7 +142,7 @@ equipped with an orientation of its once-stabilized tangent bundle. Similarly, in dimension $n-k$ we would have manifolds equipped with an orientation of their $k$ times stabilized tangent bundles. -(cf. [Stolz and Teichner].) +(cf. \cite{MR2079378}.) Probably should also have a framing of the stabilized dimensions in order to indicate which side the bounded manifold is on. For the moment just stick with unoriented manifolds.} @@ -780,23 +780,6 @@ (actions of homeomorphisms); define $k$-cat $\cC(\cdot\times W)$} -\nn{need to revise stuff below, since we no longer have the sphere axiom} - -Recall that Axiom \ref{axiom:spheres} for an $n$-category provided functors $\cC$ from $k$-spheres to sets for $0 \leq k < n$. We claim now that these functors automatically agree with the colimits we have associated to spheres in this section. \todo{} \todo{In fact, we probably should do this for balls as well!} For the remainder of this section we will write $\underrightarrow{\cC}(W)$ for the colimit associated to an arbitary manifold $W$, to distinguish it, in the case that $W$ is a ball or a sphere, from $\cC(W)$, which is part of the definition of the $n$-category. After the next three lemmas, there will be no further need for this notational distinction. - -\begin{lem} -For a $k$-ball or $k$-sphere $W$, with $0\leq k < n$, $$\underrightarrow{\cC}(W) = \cC(W).$$ -\end{lem} - -\begin{lem} -For a topological $n$-category $\cC$, and an $n$-ball $B$, $$\underrightarrow{\cC}(B) = \cC(B).$$ -\end{lem} - -\begin{lem} -For an $A_\infty$ $n$-category $\cC$, and an $n$-ball $B$, $$\underrightarrow{\cC}(B) \quism \cC(B).$$ -\end{lem} - - \subsection{Modules} Next we define plain and $A_\infty$ $n$-category modules.