text/tqftreview.tex
changeset 772 73fc4868c039
parent 771 249ccaa26fee
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   275 Put another way, the cell decompositions we consider are dual to standard cell
   275 Put another way, the cell decompositions we consider are dual to standard cell
   276 decompositions of $X$.
   276 decompositions of $X$.
   277 
   277 
   278 We will always assume that our $n$-categories have linear $n$-morphisms.
   278 We will always assume that our $n$-categories have linear $n$-morphisms.
   279 
   279 
   280 \nn{need to replace ``cell decomposition" below with something looser.  not sure what to call it.
       
   281 maybe ``nice stratification"??  the link of each piece of each stratum should be a cell decomposition of
       
   282 a sphere, but that's probably all we need.  or maybe refineable to a cell decomp?}
       
   283 
       
   284 For $n=1$, a field on a 0-manifold $P$ is a labeling of each point of $P$ with
   280 For $n=1$, a field on a 0-manifold $P$ is a labeling of each point of $P$ with
   285 an object (0-morphism) of the 1-category $C$.
   281 an object (0-morphism) of the 1-category $C$.
   286 A field on a 1-manifold $S$ consists of
   282 A field on a 1-manifold $S$ consists of
   287 \begin{itemize}
   283 \begin{itemize}
   288     \item a cell decomposition of $S$ (equivalently, a finite collection
   284     \item a cell decomposition of $S$ (equivalently, a finite collection
   354     \item a labeling of each $j$-cell by a $(k-j)$-dimensional morphism of $C$, with
   350     \item a labeling of each $j$-cell by a $(k-j)$-dimensional morphism of $C$, with
   355 domain and range determined by the labelings of the link of $j$-cell.
   351 domain and range determined by the labelings of the link of $j$-cell.
   356 \end{itemize}
   352 \end{itemize}
   357 
   353 
   358 
   354 
       
   355 It is customary when drawing string diagrams to omit identity morphisms.
       
   356 In the above context, this corresponds to erasing cells which are labeled by identity morphisms.
       
   357 The resulting structure might not, strictly speaking, be a cell complex.
       
   358 So when we write ``cell complex" above we really mean a stratification which can be
       
   359 refined to a genuine cell complex.
       
   360 
       
   361 
   359 
   362 
   360 \subsection{Local relations}
   363 \subsection{Local relations}
   361 \label{sec:local-relations}
   364 \label{sec:local-relations}
   362 
   365 
   363 For convenience we assume that fields are enriched over Vect.
   366 For convenience we assume that fields are enriched over Vect.