text/ncat.tex
changeset 111 ae196d7a310d
parent 110 a2444aa1ad31
child 112 0df8bde1c896
equal deleted inserted replaced
110:a2444aa1ad31 111:ae196d7a310d
   214 \]
   214 \]
   215 and
   215 and
   216 \[
   216 \[
   217 	(a\times D')\bullet(a\times D'') = a\times (D'\bullet D'') .
   217 	(a\times D')\bullet(a\times D'') = a\times (D'\bullet D'') .
   218 \]
   218 \]
       
   219 \nn{problem: if pinched boundary, then only one factor}
   219 Product morphisms are associative:
   220 Product morphisms are associative:
   220 \[
   221 \[
   221 	(a\times D)\times D' = a\times (D\times D') .
   222 	(a\times D)\times D' = a\times (D\times D') .
   222 \]
   223 \]
   223 (Here we are implicitly using functoriality and the obvious homeomorphism
   224 (Here we are implicitly using functoriality and the obvious homeomorphism
   446 
   447 
   447 Finally, define $\cC(W)$ to be the colimit of $\psi_\cC$.
   448 Finally, define $\cC(W)$ to be the colimit of $\psi_\cC$.
   448 In other words, for each decomposition $x$ there is a map
   449 In other words, for each decomposition $x$ there is a map
   449 $\psi_\cC(x)\to \cC(W)$, these maps are compatible with the refinement maps
   450 $\psi_\cC(x)\to \cC(W)$, these maps are compatible with the refinement maps
   450 above, and $\cC(W)$ is universal with respect to these properties.
   451 above, and $\cC(W)$ is universal with respect to these properties.
       
   452 \nn{in A-inf case, need to say more}
       
   453 
       
   454 \nn{should give more concrete description (two cases)}
   451 
   455 
   452 $\cC(W)$ is functorial with respect to homeomorphisms of $k$-manifolds.
   456 $\cC(W)$ is functorial with respect to homeomorphisms of $k$-manifolds.
   453 
   457 
   454 It is easy to see that
   458 It is easy to see that
   455 there are well-defined maps $\cC(W)\to\cC(\bd W)$, and that these maps
   459 there are well-defined maps $\cC(W)\to\cC(\bd W)$, and that these maps
   632 	M\times D \ar[r]^{\tilde{f}} \ar[d]_{\pi} & M'\times D' \ar[d]^{\pi} \\
   636 	M\times D \ar[r]^{\tilde{f}} \ar[d]_{\pi} & M'\times D' \ar[d]^{\pi} \\
   633 	M \ar[r]^{f} & M'
   637 	M \ar[r]^{f} & M'
   634 } \]
   638 } \]
   635 commutes, then we have $\tilde{f}(a\times D) = f(a)\times D'$.}
   639 commutes, then we have $\tilde{f}(a\times D) = f(a)\times D'$.}
   636 
   640 
   637 \nn{Need to say something about compatibility with gluing (of both $M$ and $D$) above.}
   641 \nn{Need to add compatibility with various things, as in the n-cat version of this axiom above.}
   638 
   642 
   639 \nn{** marker --- resume revising here **}
   643 \nn{** marker --- resume revising here **}
   640 
   644 
   641 There are two alternatives for the next axiom, according whether we are defining
   645 There are two alternatives for the next axiom, according whether we are defining
   642 modules for plain $n$-categories or $A_\infty$ $n$-categories.
   646 modules for plain $n$-categories or $A_\infty$ $n$-categories.
   717 $\cN$ determines 
   721 $\cN$ determines 
   718 a functor $\psi_\cN$ from $\cJ(W)$ to the category of sets 
   722 a functor $\psi_\cN$ from $\cJ(W)$ to the category of sets 
   719 (possibly with additional structure if $k=n$).
   723 (possibly with additional structure if $k=n$).
   720 For a decomposition $x = (X_a, M_{ib})$ in $\cJ(W)$, define $\psi_\cN(x)$ to be the subset
   724 For a decomposition $x = (X_a, M_{ib})$ in $\cJ(W)$, define $\psi_\cN(x)$ to be the subset
   721 \[
   725 \[
   722 	\psi_\cN(x) \sub (\prod_a \cC(X_a)) \prod (\prod_{ib} \cN_i(M_{ib}))
   726 	\psi_\cN(x) \sub (\prod_a \cC(X_a)) \times (\prod_{ib} \cN_i(M_{ib}))
   723 \]
   727 \]
   724 such that the restrictions to the various pieces of shared boundaries amongst the
   728 such that the restrictions to the various pieces of shared boundaries amongst the
   725 $X_a$ and $M_{ib}$ all agree.
   729 $X_a$ and $M_{ib}$ all agree.
   726 (Think fibered product.)
   730 (Think fibered product.)
   727 If $x$ is a refinement of $y$, define a map $\psi_\cN(x)\to\psi_\cN(y)$
   731 If $x$ is a refinement of $y$, define a map $\psi_\cN(x)\to\psi_\cN(y)$
   783 $\cC$, $\cM$ and $\cM'$ determine 
   787 $\cC$, $\cM$ and $\cM'$ determine 
   784 a functor $\psi$ from $\cJ(D)$ to the category of sets 
   788 a functor $\psi$ from $\cJ(D)$ to the category of sets 
   785 (possibly with additional structure if $k=n$).
   789 (possibly with additional structure if $k=n$).
   786 For a decomposition $x = (X_a, M_b, M'_c)$ in $\cJ(D)$, define $\psi(x)$ to be the subset
   790 For a decomposition $x = (X_a, M_b, M'_c)$ in $\cJ(D)$, define $\psi(x)$ to be the subset
   787 \[
   791 \[
   788 	\psi(x) \sub (\prod_a \cC(X_a)) \prod (\prod_b \cM(M_b)) \prod (\prod_c \cM'(M'_c))
   792 	\psi(x) \sub (\prod_a \cC(X_a)) \times (\prod_b \cM(M_b)) \times (\prod_c \cM'(M'_c))
   789 \]
   793 \]
   790 such that the restrictions to the various pieces of shared boundaries amongst the
   794 such that the restrictions to the various pieces of shared boundaries amongst the
   791 $X_a$, $M_b$ and $M'_c$ all agree.
   795 $X_a$, $M_b$ and $M'_c$ all agree.
   792 (Think fibered product.)
   796 (Think fibered product.)
   793 If $x$ is a refinement of $y$, define a map $\psi(x)\to\psi(y)$
   797 If $x$ is a refinement of $y$, define a map $\psi(x)\to\psi(y)$