diff -r 5bb1cbe49c40 -r ef8fac44a8aa text/ncat.tex --- a/text/ncat.tex Mon May 31 17:27:17 2010 -0700 +++ b/text/ncat.tex Mon May 31 23:42:37 2010 -0700 @@ -95,7 +95,7 @@ Morphisms are modeled on balls, so their boundaries are modeled on spheres. In other words, we need to extend the functors $\cC_{k-1}$ from balls to spheres, for $1\le k \le n$. -At first might seem that we need another axiom for this, but in fact once we have +At first it might seem that we need another axiom for this, but in fact once we have all the axioms in the subsection for $0$ through $k-1$ we can use a coend construction, as described in Subsection \ref{ss:ncat-coend} below, to extend $\cC_{k-1}$ to spheres (and any other manifolds): @@ -107,6 +107,7 @@ homeomorphisms to the category of sets and bijections. \end{prop} +We postpone the proof of this result until after we've actually given all the axioms. Note that defining this functor for some $k$ only requires the data described in Axiom \ref{axiom:morphisms} at level $k$, along with the data described in other Axioms at lower levels. %In fact, the functors for spheres are entirely determined by the functors for balls and the subsequent axioms. (In particular, $\cC(S^k)$ is the colimit of $\cC$ applied to decompositions of $S^k$ into balls.) However, it is easiest to think of it as additional data at this point. @@ -515,6 +516,8 @@ (Note that homotopy invariance implies isotopy invariance.) For $a\in \cC(X)$ define the product morphism $a\times D \in \cC(X\times D)$ to be $a\circ\pi_X$, where $\pi_X : X\times D \to X$ is the projection. + +Recall we described a system of fields and local relations based on maps to $T$ in Example \ref{ex:maps-to-a-space(fields)} above. Constructing a system of fields from $\pi_{\leq n}(T)$ recovers that example. \end{example} \begin{example}[Maps to a space, with a fiber] @@ -556,6 +559,9 @@ Define $\cC(X; c)$, for $X$ an $n$-ball, to be the dual Hilbert space $A(X\times F; c)$. \nn{refer elsewhere for details?} + + +Recall we described a system of fields and local relations based on a `traditional $n$-category' $C$ in Example \ref{ex:traditional-n-categories(fields)} above. Constructing a system of fields from $\cC$ recovers that example. \end{example} Finally, we describe a version of the bordism $n$-category suitable to our definitions.