text/ncat.tex
changeset 783 d450abe6decb
parent 782 d8ae97449506
child 784 bd9538de8248
equal deleted inserted replaced
782:d8ae97449506 783:d450abe6decb
  1065 (see Example \ref{sin1x-example}), we must define $\psi_{\cC;W}(x)$ in a more roundabout way.
  1065 (see Example \ref{sin1x-example}), we must define $\psi_{\cC;W}(x)$ in a more roundabout way.
  1066 
  1066 
  1067 Inductively, we may assume that we have already defined the colimit $\cl\cC(M)$ for $k{-}1$-manifolds $M$.
  1067 Inductively, we may assume that we have already defined the colimit $\cl\cC(M)$ for $k{-}1$-manifolds $M$.
  1068 (To start the induction, we define $\cl\cC(M)$, where $M = \du_a P_a$ is a 0-manifold and each $P_a$ is
  1068 (To start the induction, we define $\cl\cC(M)$, where $M = \du_a P_a$ is a 0-manifold and each $P_a$ is
  1069 a 0-ball, to be $\prod_a \cC(P_a)$.)
  1069 a 0-ball, to be $\prod_a \cC(P_a)$.)
       
  1070 We also assume, inductively, that we have gluing and restriction maps for colimits of $k{-}1$-manifolds.
  1070 
  1071 
  1071 Let $\du_a X_a = M_0\to\cdots\to M_m = W$ be a ball decomposition compatible with $x$.
  1072 Let $\du_a X_a = M_0\to\cdots\to M_m = W$ be a ball decomposition compatible with $x$.
  1072 Let $\bd M_i = N_i \cup Y_i \cup Y'_i$, where $Y_i$ and $Y'_i$ are glued together to produce $M_{i+1}$.
  1073 Let $\bd M_i = N_i \cup Y_i \cup Y'_i$, where $Y_i$ and $Y'_i$ are glued together to produce $M_{i+1}$.
  1073 We will define $\psi_{\cC;W}(x)$ be be the subset of $\prod_a \cC(X_a)$ which satisfies a series of conditions
  1074 We will define $\psi_{\cC;W}(x)$ be be the subset of $\prod_a \cC(X_a)$ which satisfies a series of conditions
  1074 related to the gluings $M_{i-1} \to M_i$, $1\le i \le m$.
  1075 related to the gluings $M_{i-1} \to M_i$, $1\le i \le m$.
  1096 Rather than try to prove a similar result for arbitrary
  1097 Rather than try to prove a similar result for arbitrary
  1097 permissible decompositions, we instead require compatibility with all ways of gluing up the decomposition.)
  1098 permissible decompositions, we instead require compatibility with all ways of gluing up the decomposition.)
  1098 
  1099 
  1099 If $x$ is a refinement of $y$, the map $\psi_{\cC;W}(x) \to \psi_{\cC;W}(y)$ is given by the composition maps of $\cC$.
  1100 If $x$ is a refinement of $y$, the map $\psi_{\cC;W}(x) \to \psi_{\cC;W}(y)$ is given by the composition maps of $\cC$.
  1100 
  1101 
  1101 
       
  1102 \nn{...}
       
  1103 
  1102 
  1104 \nn{to do: define splittability and restrictions for colimits}
  1103 \nn{to do: define splittability and restrictions for colimits}
  1105 
  1104 
  1106 \noop{ %%%%%%%%%%%%%%%%%%%%%%%
  1105 \noop{ %%%%%%%%%%%%%%%%%%%%%%%
  1107 For pedagogical reasons, let us first consider the case of a decomposition $y$ of $W$ 
  1106 For pedagogical reasons, let us first consider the case of a decomposition $y$ of $W$