text/ncat.tex
changeset 105 d2409e357801
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child 106 dd4b4ac15023
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   549 where $X$ is a $k$-ball or $k{-}1$-sphere and in the product $X\times J$ we pinch 
   549 where $X$ is a $k$-ball or $k{-}1$-sphere and in the product $X\times J$ we pinch 
   550 above the non-marked boundary component of $J$.
   550 above the non-marked boundary component of $J$.
   551 \nn{give figure for this, or say more?}
   551 \nn{give figure for this, or say more?}
   552 Then $\cE$ has the structure of an $n{-}1$-category.
   552 Then $\cE$ has the structure of an $n{-}1$-category.
   553 
   553 
       
   554 All marked $k$-balls are homeomorphic, unless $k = 1$ and our manifolds
       
   555 are oriented or Spin (but not unoriented or $\text{Pin}_\pm$).
       
   556 In this case ($k=1$ and oriented or Spin), there are two types
       
   557 of marked 1-balls, call them left-marked and right-marked,
       
   558 and hence there are two types of modules, call them right modules and left modules.
       
   559 In all other cases ($k>1$ or unoriented or $\text{Pin}_\pm$),
       
   560 there is no left/right module distinction.
       
   561 
       
   562 \medskip
       
   563 
       
   564 Next we consider tensor products (or, more generally, self tensor products
       
   565 or coends).
       
   566 
       
   567 
   554 
   568 
   555 \medskip
   569 \medskip
   556 \hrule
   570 \hrule
   557 \medskip
   571 \medskip
   558 
   572 
   562 
   576 
   563 Stuff that remains to be done (either below or in an appendix or in a separate section or in
   577 Stuff that remains to be done (either below or in an appendix or in a separate section or in
   564 a separate paper):
   578 a separate paper):
   565 \begin{itemize}
   579 \begin{itemize}
   566 \item tensor products
   580 \item tensor products
   567 \item blob complex is an example of an $A_\infty$ $n$-category
       
   568 \item fundamental $n$-groupoid is an example of an $A_\infty$ $n$-category
       
   569 \item traditional $n$-cat defs (e.g. *-1-cat, pivotal 2-cat) imply our def of plain $n$-cat
   581 \item traditional $n$-cat defs (e.g. *-1-cat, pivotal 2-cat) imply our def of plain $n$-cat
   570 \item conversely, our def implies other defs
   582 \item conversely, our def implies other defs
       
   583 \item do same for modules; maybe an appendix on relating topological
       
   584 vs traditional defs, $n = 1,2$, $A_\infty$ or not, cats, modules, tensor products
   571 \item traditional $A_\infty$ 1-cat def implies our def
   585 \item traditional $A_\infty$ 1-cat def implies our def
   572 \item ... and vice-versa (already done in appendix)
   586 \item ... and vice-versa (already done in appendix)
   573 \item say something about unoriented vs oriented vs spin vs pin for $n=1$ (and $n=2$?)
   587 \item say something about unoriented vs oriented vs spin vs pin for $n=1$ (and $n=2$?)
   574 \item spell out what difference (if any) Top vs PL vs Smooth makes
   588 \item spell out what difference (if any) Top vs PL vs Smooth makes
   575 \item explain relation between old-fashioned blob homology and new-fangled blob homology
   589 \item explain relation between old-fashioned blob homology and new-fangled blob homology
       
   590 \item define $n{+}1$-cat of $n$-cats; discuss Morita equivalence
   576 \end{itemize}
   591 \end{itemize}
   577 
   592 
   578 
   593