text/ncat.tex
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   395 \draw[->,red,line width=2pt] (-2.83,-1.5) -- (-2.83,-2.5);
   395 \draw[->,red,line width=2pt] (-2.83,-1.5) -- (-2.83,-2.5);
   396 \end{tikzpicture}
   396 \end{tikzpicture}
   397 $$
   397 $$
   398 \caption{Examples of pinched products}\label{pinched_prods}
   398 \caption{Examples of pinched products}\label{pinched_prods}
   399 \end{figure}
   399 \end{figure}
   400 (The need for a strengthened version will become apparent in Appendix \ref{sec:comparing-defs}
   400 The need for a strengthened version will become apparent in Appendix \ref{sec:comparing-defs}
   401 where we construct a traditional category from a disk-like category.)
   401 where we construct a traditional category from a disk-like category.
       
   402 For example, ``half-pinched" products of 1-balls are used to construct weak identities for 1-morphisms
       
   403 in 2-categories.
       
   404 We also need fully-pinched products to define collar maps below (see Figure \ref{glue-collar}).
       
   405 
   402 Define a {\it pinched product} to be a map
   406 Define a {\it pinched product} to be a map
   403 \[
   407 \[
   404 	\pi: E\to X
   408 	\pi: E\to X
   405 \]
   409 \]
   406 such that $E$ is a $k{+}m$-ball, $X$ is a $k$-ball ($m\ge 1$), and $\pi$ is locally modeled
   410 such that $E$ is a $k{+}m$-ball, $X$ is a $k$-ball ($m\ge 1$), and $\pi$ is locally modeled