text/ncat.tex
changeset 535 07b79f81c956
parent 531 da9bf150bf3d
child 543 0bc6fa29b62a
equal deleted inserted replaced
534:2b1d52c41ac5 535:07b79f81c956
  1091 \item elements $a_i\in \psi(x_i)$ and $b_i\in \psi(v_i)$, with $a_0 = a$ and $a_k = \hat{a}$, 
  1091 \item elements $a_i\in \psi(x_i)$ and $b_i\in \psi(v_i)$, with $a_0 = a$ and $a_k = \hat{a}$, 
  1092 such that $b_i$ and $b_{i+1}$both map to (glue up to) $a_i$.
  1092 such that $b_i$ and $b_{i+1}$both map to (glue up to) $a_i$.
  1093 \end{itemize}
  1093 \end{itemize}
  1094 In other words, we have a zig-zag of equivalences starting at $a$ and ending at $\hat{a}$.
  1094 In other words, we have a zig-zag of equivalences starting at $a$ and ending at $\hat{a}$.
  1095 The idea of the proof is to produce a similar zig-zag where everything antirefines to the same
  1095 The idea of the proof is to produce a similar zig-zag where everything antirefines to the same
  1096 disjoint union of balls, and then invoke the associativity axiom \ref{nca-assoc}.
  1096 disjoint union of balls, and then invoke Axiom \ref{nca-assoc} which ensures associativity.
  1097 \nn{hmmm... it would be nicer if this were ``7.xx" instead of ``4"}
       
  1098 
  1097 
  1099 Let $z$ be a decomposition of $W$ which is in general position with respect to all of the 
  1098 Let $z$ be a decomposition of $W$ which is in general position with respect to all of the 
  1100 $x_i$'s and $v_i$'s.
  1099 $x_i$'s and $v_i$'s.
  1101 There there decompositions $x'_i$ and $v'_i$ (for all $i$) such that
  1100 There there decompositions $x'_i$ and $v'_i$ (for all $i$) such that
  1102 \begin{itemize}
  1101 \begin{itemize}