diff -r 9c908b698da5 -r 3b228545d9bb text/ncat.tex --- a/text/ncat.tex Fri Nov 06 21:57:13 2009 +0000 +++ b/text/ncat.tex Sat Nov 07 15:23:53 2009 +0000 @@ -143,7 +143,7 @@ \xxpar{Domain $+$ range $\to$ boundary:} {Let $S = B_1 \cup_E B_2$, where $S$ is a $k$-sphere ($0\le k\le n-1$), -$B_i$ is a $k$-ball, and $E = B_1\cap B_2$ is a $k{-}1$-sphere. +$B_i$ is a $k$-ball, and $E = B_1\cap B_2$ is a $k{-}1$-sphere (Figure \ref{blah3}). Let $\cC(B_1) \times_{\cC(E)} \cC(B_2)$ denote the fibered product of the two maps $\bd: \cC(B_i)\to \cC(E)$. Then (axiom) we have an injective map @@ -152,6 +152,10 @@ \] which is natural with respect to the actions of homeomorphisms.} +\begin{figure}[!ht] +$$\mathfig{.4}{tempkw/blah3}$$ +\caption{Combining two balls to get a full boundary}\label{blah3}\end{figure} + Note that we insist on injectivity above. Let $\cC(S)_E$ denote the image of $\gl_E$. @@ -175,7 +179,7 @@ \xxpar{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. +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. Note that each of $B$, $B_1$ and $B_2$ has its boundary split into two $k{-}1$-balls by $E$. We have restriction (domain or range) maps $\cC(B_i)_E \to \cC(Y)$. @@ -189,9 +193,17 @@ If $k < n$ we require that $\gl_Y$ is injective. (For $k=n$, see below.)} +\begin{figure}[!ht] +$$\mathfig{.4}{tempkw/blah5}$$ +\caption{From two balls to one ball}\label{blah5}\end{figure} + \xxpar{Strict associativity:} {The composition (gluing) maps above are strictly associative.} +\begin{figure}[!ht] +$$\mathfig{.65}{tempkw/blah6}$$ +\caption{An example of strict associativity}\label{blah6}\end{figure} + Notation: $a\bullet b \deq \gl_Y(a, b)$ and/or $a\cup b \deq \gl_Y(a, b)$. In the other direction, we will call the projection from $\cC(B)_E$ to $\cC(B_i)_E$ a {\it restriction} map and write $\res_{B_i}(a)$ for $a\in \cC(B)_E$. @@ -212,7 +224,11 @@ map from an appropriate subset (like a fibered product) of $\cC(B_1)\times\cdots\times\cC(B_m)$ to $\cC(B)$, and these various $m$-fold composition maps satisfy an -operad-type strict associativity condition.} +operad-type strict associativity condition (Figure \ref{blah7}).} + +\begin{figure}[!ht] +$$\mathfig{.8}{tempkw/blah7}$$ +\caption{Operadish composition and associativity}\label{blah7}\end{figure} The next axiom is related to identity morphisms, though that might not be immediately obvious.