text/ncat.tex
changeset 727 0ec80a7773dc
parent 726 d847565d489a
child 730 58c9e149d05a
equal deleted inserted replaced
726:d847565d489a 727:0ec80a7773dc
   249 Note that each of $B$, $B_1$ and $B_2$ has its boundary split into two $k{-}1$-balls by $E$.
   249 Note that each of $B$, $B_1$ and $B_2$ has its boundary split into two $k{-}1$-balls by $E$.
   250 We have restriction (domain or range) maps $\cC(B_i)\trans E \to \cC(Y)$.
   250 We have restriction (domain or range) maps $\cC(B_i)\trans E \to \cC(Y)$.
   251 Let $\cC(B_1)\trans E \times_{\cC(Y)} \cC(B_2)\trans E$ denote the fibered product of these two maps. 
   251 Let $\cC(B_1)\trans E \times_{\cC(Y)} \cC(B_2)\trans E$ denote the fibered product of these two maps. 
   252 We have a map
   252 We have a map
   253 \[
   253 \[
   254 	\gl_Y : \cC(B_1)\trans E \times_{\cC(Y)} \cC(B_2)\trans E \to \cC(B)_E
   254 	\gl_Y : \cC(B_1)\trans E \times_{\cC(Y)} \cC(B_2)\trans E \to \cC(B)\trans E
   255 \]
   255 \]
   256 which is natural with respect to the actions of homeomorphisms, and also compatible with restrictions
   256 which is natural with respect to the actions of homeomorphisms, and also compatible with restrictions
   257 to the intersection of the boundaries of $B$ and $B_i$.
   257 to the intersection of the boundaries of $B$ and $B_i$.
   258 If $k < n$,
   258 If $k < n$,
   259 or if $k=n$ and we are in the $A_\infty$ case, 
   259 or if $k=n$ and we are in the $A_\infty$ case, 
   697 
   697 
   698 An $n$-category consists of the following data:
   698 An $n$-category consists of the following data:
   699 \begin{itemize}
   699 \begin{itemize}
   700 \item functors $\cC_k$ from $k$-balls to sets, $0\le k\le n$ (Axiom \ref{axiom:morphisms});
   700 \item functors $\cC_k$ from $k$-balls to sets, $0\le k\le n$ (Axiom \ref{axiom:morphisms});
   701 \item boundary natural transformations $\cC_k \to \cl{\cC}_{k-1} \circ \bd$ (Axiom \ref{nca-boundary});
   701 \item boundary natural transformations $\cC_k \to \cl{\cC}_{k-1} \circ \bd$ (Axiom \ref{nca-boundary});
   702 \item ``composition'' or ``gluing'' maps $\gl_Y : \cC(B_1)\trans E \times_{\cC(Y)} \cC(B_2)\trans E \to \cC(B_1\cup_Y B_2)_E$ (Axiom \ref{axiom:composition});
   702 \item ``composition'' or ``gluing'' maps $\gl_Y : \cC(B_1)\trans E \times_{\cC(Y)} \cC(B_2)\trans E \to \cC(B_1\cup_Y B_2)\trans E$ (Axiom \ref{axiom:composition});
   703 \item ``product'' or ``identity'' maps $\pi^*:\cC(X)\to \cC(E)$ for each pinched product $\pi:E\to X$ (Axiom \ref{axiom:product});
   703 \item ``product'' or ``identity'' maps $\pi^*:\cC(X)\to \cC(E)$ for each pinched product $\pi:E\to X$ (Axiom \ref{axiom:product});
   704 \item if enriching in an auxiliary category, additional structure on $\cC_n(X; c)$;
   704 \item if enriching in an auxiliary category, additional structure on $\cC_n(X; c)$;
   705 \item in the $A_\infty$ case, an action of $C_*(\Homeo_\bd(X))$, and similarly for families of collar maps (Axiom \ref{axiom:families}).
   705 \item in the $A_\infty$ case, an action of $C_*(\Homeo_\bd(X))$, and similarly for families of collar maps (Axiom \ref{axiom:families}).
   706 \end{itemize}
   706 \end{itemize}
   707 The above data must satisfy the following conditions:
   707 The above data must satisfy the following conditions: