text/ncat.tex
changeset 778 760cc71a0424
parent 775 9ea10b1adfaa
child 782 d8ae97449506
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777:682fd0520c66 778:760cc71a0424
  1279 \begin{figure}[t]
  1279 \begin{figure}[t]
  1280 $$\mathfig{.55}{ncat/boundary-collar}$$
  1280 $$\mathfig{.55}{ncat/boundary-collar}$$
  1281 \caption{From manifold with boundary collar to marked ball}\label{blah15}\end{figure}
  1281 \caption{From manifold with boundary collar to marked ball}\label{blah15}\end{figure}
  1282 
  1282 
  1283 Define the boundary of a marked $k$-ball $(B, N)$ to be the pair $(\bd B \setmin N, \bd N)$.
  1283 Define the boundary of a marked $k$-ball $(B, N)$ to be the pair $(\bd B \setmin N, \bd N)$.
  1284 Call such a thing a {marked $k{-}1$-hemisphere}.
  1284 Call such a thing a {\it marked $k{-}1$-hemisphere}.
       
  1285 (A marked $k{-}1$-hemisphere is, of course, just a $k{-}1$-ball with its entire boundary marked.
       
  1286 We call it a hemisphere instead of a ball because it plays a role analogous
       
  1287 to the $k{-}1$-spheres in the $n$-category definition.)
  1285 
  1288 
  1286 \begin{lem}
  1289 \begin{lem}
  1287 \label{lem:hemispheres}
  1290 \label{lem:hemispheres}
  1288 {For each $0 \le k \le n-1$, we have a functor $\cl\cM_k$ from 
  1291 {For each $0 \le k \le n-1$, we have a functor $\cl\cM_k$ from 
  1289 the category of marked $k$-hemispheres and 
  1292 the category of marked $k$-hemispheres and