text/ncat.tex
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   332 \end{enumerate}
   332 \end{enumerate}
   333 \end{axiom}
   333 \end{axiom}
   334 
   334 
   335 We will need to strengthen the above preliminary version of the axiom to allow
   335 We will need to strengthen the above preliminary version of the axiom to allow
   336 for products which are ``pinched" in various ways along their boundary.
   336 for products which are ``pinched" in various ways along their boundary.
   337 (See Figure xxxx.)
   337 (See Figure \ref{pinched_prods}.)
       
   338 \begin{figure}[t]
       
   339 $$\mathfig{.8}{tempkw/pinched_prods}$$
       
   340 \caption{Examples of pinched products}\label{pinched_prods}
       
   341 \end{figure}
   338 (The need for a strengthened version will become apparent in appendix \ref{sec:comparing-defs}
   342 (The need for a strengthened version will become apparent in appendix \ref{sec:comparing-defs}
   339 where we construct a traditional category from a topological category.)
   343 where we construct a traditional category from a topological category.)
   340 Define a {\it pinched product} to be a map
   344 Define a {\it pinched product} to be a map
   341 \[
   345 \[
   342 	\pi: E\to X
   346 	\pi: E\to X
   357 
   361 
   358 A {\it sub pinched product} is a sub-$m$-ball $E'\sub E$ such that the restriction
   362 A {\it sub pinched product} is a sub-$m$-ball $E'\sub E$ such that the restriction
   359 $\pi:E'\to \pi(E')$ is again a pinched product.
   363 $\pi:E'\to \pi(E')$ is again a pinched product.
   360 A {union} of pinched products is a decomposition $E = \cup_i E_i$
   364 A {union} of pinched products is a decomposition $E = \cup_i E_i$
   361 such that each $E_i\sub E$ is a sub pinched product.
   365 such that each $E_i\sub E$ is a sub pinched product.
   362 (See Figure xxxx.)
   366 (See Figure \ref{pinched_prod_unions}.)
       
   367 \begin{figure}[t]
       
   368 $$\mathfig{.8}{tempkw/pinched_prod_unions}$$
       
   369 \caption{Unions of pinched products}\label{pinched_prod_unions}
       
   370 \end{figure}
   363 
   371 
   364 The product axiom will give a map $\pi^*:\cC(X)\to \cC(E)$ for each pinched product
   372 The product axiom will give a map $\pi^*:\cC(X)\to \cC(E)$ for each pinched product
   365 $\pi:E\to X$.
   373 $\pi:E\to X$.
   366 Morphisms in the image of $\pi^*$ will be called product morphisms.
   374 Morphisms in the image of $\pi^*$ will be called product morphisms.
   367 Before stating the axiom, we illustrate it in our two motivating examples of $n$-categories.
   375 Before stating the axiom, we illustrate it in our two motivating examples of $n$-categories.