diff -r 62a402dd3e6e -r b138ee4a5938 text/ncat.tex --- a/text/ncat.tex Thu Sep 23 18:10:35 2010 -0700 +++ b/text/ncat.tex Fri Sep 24 15:32:55 2010 -0700 @@ -45,7 +45,11 @@ By ``a $k$-ball" we mean any $k$-manifold which is homeomorphic to the standard $k$-ball. We {\it do not} assume that it is equipped with a -preferred homeomorphism to the standard $k$-ball, and the same applies to ``a $k$-sphere" below. \nn{List the axiom numbers here, mentioning alternate versions, and also the same in the module section.} +preferred homeomorphism to the standard $k$-ball, and the same applies to ``a $k$-sphere" below. + +The axioms for an $n$-category are spread throughout this section. +Collecting these together, an $n$-category is a gadget satisfying Axioms \ref{axiom:morphisms}, \ref{nca-boundary}, \ref{axiom:composition}, \ref{nca-assoc}, \ref{axiom:product} and \ref{axiom:extended-isotopies}; for an $A_\infty$ $n$-category, we replace Axiom \ref{axiom:extended-isotopies} with Axiom \ref{axiom:families}. + Given a homeomorphism $f:X\to Y$ between $k$-balls (not necessarily fixed on the boundary), we want a corresponding @@ -218,6 +222,7 @@ one general type of composition which can be in any ``direction". \begin{axiom}[Composition] +\label{axiom:composition} Let $B = B_1 \cup_Y B_2$, where $B$, $B_1$ and $B_2$ are $k$-balls ($0\le k\le n$) and $Y = B_1\cap B_2$ is a $k{-}1$-ball (Figure \ref{blah5}). Let $E = \bd Y$, which is a $k{-}2$-sphere. @@ -467,6 +472,7 @@ %\addtocounter{axiom}{-1} \begin{axiom}[Product (identity) morphisms] +\label{axiom:product} For each pinched product $\pi:E\to X$, with $X$ a $k$-ball and $E$ a $k{+}m$-ball ($m\ge 1$), there is a map $\pi^*:\cC(X)\to \cC(E)$. These maps must satisfy the following conditions. @@ -612,6 +618,7 @@ %\addtocounter{axiom}{-1} \begin{axiom}[\textup{\textbf{[$A_\infty$ version]}} Families of homeomorphisms act in dimension $n$.] +\label{axiom:families} For each $n$-ball $X$ and each $c\in \cl{\cC}(\bd X)$ we have a map of chain complexes \[ C_*(\Homeo_\bd(X))\ot \cC(X; c) \to \cC(X; c) . @@ -1831,7 +1838,7 @@ where $B^j$ is the standard $j$-ball. A 1-marked $k$-ball can be decomposed in various ways into smaller balls, which are either (a) smaller 1-marked $k$-balls, (b) 0-marked $k$-balls, or (c) plain $k$-balls. -(See Figure \nn{need figure, and improve caption on other figure}.) +(See Figure \ref{subdividing1marked}.) We now proceed as in the above module definitions. \begin{figure}[t] \centering @@ -1849,6 +1856,41 @@ \label{feb21d} \end{figure} +\begin{figure}[t] \centering +\begin{tikzpicture}[baseline,line width = 2pt] +\draw[blue][fill=blue!15!white] (0,0) circle (2); +\fill[red] (0,0) circle (0.1); +\foreach \qm/\qa/\n in {70/-30/0, 120/95/1, -120/180/2} { + \draw[red] (0,0) -- (\qm:2); +% \path (\qa:1) node {\color{green!50!brown} $\cA_\n$}; +% \path (\qm+20:2.5) node(M\n) {\color{green!50!brown} $\cM_\n$}; +% \draw[line width=1pt, green!50!brown, ->] (M\n.\qm+135) to[out=\qm+135,in=\qm+90] (\qm+5:1.3); +} + + +\begin{scope}[black, thin] +\clip (0,0) circle (2); +\draw (0:1) -- (90:1) -- (180:1) -- (270:1) -- cycle; +\draw (90:1) -- (90:2.1); +\draw (180:1) -- (180:2.1); +\draw (270:1) -- (270:2.1); +\draw (0:1) -- (15:2.1); +\draw (0:1) -- (315:1.5) -- (270:1); +\draw (315:1.5) -- (315:2.1); +\end{scope} + +\node(0marked) at (2.5,2.25) {$0$-marked ball}; +\node(1marked) at (3.5,1) {$1$-marked ball}; +\node(plain) at (3,-1) {plain ball}; +\draw[line width=1pt, green!50!brown, ->] (0marked.270) to[out=270,in=45] (50:1.1); +\draw[line width=1pt, green!50!brown, ->] (1marked.225) to[out=270,in=45] (0.4,0.1); +\draw[line width=1pt, green!50!brown, ->] (plain.90) to[out=135,in=45] (-45:1); + +\end{tikzpicture} +\caption{Subdividing a $1$-marked ball into plain, $0$-marked and $1$-marked balls.} +\label{subdividing1marked} +\end{figure} + A $n$-category 1-sphere module is, among other things, an $n{-}2$-category $\cD$ with \[ \cD(X) \deq \cM(X\times C(S)) . @@ -2213,8 +2255,7 @@ For $n=1$ we have to check an additional ``global" relations corresponding to rotating the 0-sphere $E$ around the 1-sphere $\bd X$. But if $n=1$, then we are in the case of ordinary algebroids and bimodules, -and this is just the well-known ``Frobenius reciprocity" result for bimodules. -\nn{find citation for this. Evans and Kawahigashi? Bisch!} +and this is just the well-known ``Frobenius reciprocity" result for bimodules \cite{MR1424954}. \medskip