text/deligne.tex
changeset 301 f956f235213a
parent 300 febbf06c3610
child 319 121c580d5ef7
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    35 	C_*(FG_k)\otimes \hom(\bc^C_*(I), \bc^C_*(I))\otimes\cdots
    35 	C_*(FG_k)\otimes \hom(\bc^C_*(I), \bc^C_*(I))\otimes\cdots
    36 	\otimes \hom(\bc^C_*(I), \bc^C_*(I))
    36 	\otimes \hom(\bc^C_*(I), \bc^C_*(I))
    37 	  \to  \hom(\bc^C_*(I), \bc^C_*(I)) .
    37 	  \to  \hom(\bc^C_*(I), \bc^C_*(I)) .
    38 \]
    38 \]
    39 See Figure \ref{delfig1}.
    39 See Figure \ref{delfig1}.
    40 \begin{figure}[!ht]
    40 \begin{figure}[t]
    41 $$\mathfig{.9}{deligne/intervals}$$
    41 $$\mathfig{.9}{deligne/intervals}$$
    42 \caption{A fat graph}\label{delfig1}\end{figure}
    42 \caption{A fat graph}\label{delfig1}\end{figure}
    43 We emphasize that in $\hom(\bc^C_*(I), \bc^C_*(I))$ we are thinking of $\bc^C_*(I)$ as a module
    43 We emphasize that in $\hom(\bc^C_*(I), \bc^C_*(I))$ we are thinking of $\bc^C_*(I)$ as a module
    44 for the $A_\infty$ 1-category associated to $\bd I$, and $\hom$ means the 
    44 for the $A_\infty$ 1-category associated to $\bd I$, and $\hom$ means the 
    45 morphisms of such modules as defined in 
    45 morphisms of such modules as defined in 
    63 It should now be clear how to generalize this to higher dimensions.
    63 It should now be clear how to generalize this to higher dimensions.
    64 In the sequence-of-surgeries description above, we never used the fact that the manifolds
    64 In the sequence-of-surgeries description above, we never used the fact that the manifolds
    65 involved were 1-dimensional.
    65 involved were 1-dimensional.
    66 Thus we can define an $n$-dimensional fat graph to be a sequence of general surgeries
    66 Thus we can define an $n$-dimensional fat graph to be a sequence of general surgeries
    67 on an $n$-manifold (Figure \ref{delfig2}).
    67 on an $n$-manifold (Figure \ref{delfig2}).
    68 \begin{figure}[!ht]
    68 \begin{figure}[t]
    69 $$\mathfig{.9}{deligne/manifolds}$$
    69 $$\mathfig{.9}{deligne/manifolds}$$
    70 \caption{An  $n$-dimensional fat graph}\label{delfig2}
    70 \caption{An $n$-dimensional fat graph}\label{delfig2}
    71 \end{figure}
    71 \end{figure}
    72 
    72 
    73 More specifically, an $n$-dimensional fat graph ($n$-FG for short) consists of:
    73 More specifically, an $n$-dimensional fat graph ($n$-FG for short) consists of:
    74 \begin{itemize}
    74 \begin{itemize}
    75 \item ``Upper" $n$-manifolds $M_0,\ldots,M_k$ and ``lower" $n$-manifolds $N_0,\ldots,N_k$,
    75 \item ``Upper" $n$-manifolds $M_0,\ldots,M_k$ and ``lower" $n$-manifolds $N_0,\ldots,N_k$,
    86 \end{eqnarray*}
    86 \end{eqnarray*}
    87 Each $f_i$ should be the identity restricted to $E_0$.
    87 Each $f_i$ should be the identity restricted to $E_0$.
    88 \end{itemize}
    88 \end{itemize}
    89 We can think of the above data as encoding the union of the mapping cylinders $C(f_0),\ldots,C(f_k)$,
    89 We can think of the above data as encoding the union of the mapping cylinders $C(f_0),\ldots,C(f_k)$,
    90 with $C(f_i)$ glued to $C(f_{i+1})$ along $R_{i+1}$
    90 with $C(f_i)$ glued to $C(f_{i+1})$ along $R_{i+1}$
    91 (see Figure xxxx).
    91 (see Figure \ref{xdfig2}).
       
    92 \begin{figure}[t]
       
    93 $$\mathfig{.9}{tempkw/dfig2}$$
       
    94 \caption{$n$-dimensional fat graph from mapping cylinders}\label{xdfig2}
       
    95 \end{figure}
    92 The $n$-manifolds are the ``$n$-dimensional graph" and the $I$ direction of the mapping cylinders is the ``fat" part.
    96 The $n$-manifolds are the ``$n$-dimensional graph" and the $I$ direction of the mapping cylinders is the ``fat" part.
    93 We regard two such fat graphs as the same if there is a homeomorphism between them which is the 
    97 We regard two such fat graphs as the same if there is a homeomorphism between them which is the 
    94 identity on the boundary and which preserves the 1-dimensional fibers coming from the mapping
    98 identity on the boundary and which preserves the 1-dimensional fibers coming from the mapping
    95 cylinders.
    99 cylinders.
    96 More specifically, we impose the following two equivalence relations:
   100 More specifically, we impose the following two equivalence relations:
   100 	(\ldots, R_{i-1}, R_i, R_{i+1}, \ldots) &\to& (\ldots, R_{i-1}, R'_i, R_{i+1}, \ldots) \\
   104 	(\ldots, R_{i-1}, R_i, R_{i+1}, \ldots) &\to& (\ldots, R_{i-1}, R'_i, R_{i+1}, \ldots) \\
   101 	(\ldots, f_{i-1}, f_i, \ldots) &\to& (\ldots, g\circ f_{i-1}, f_i\circ g^{-1}, \ldots),
   105 	(\ldots, f_{i-1}, f_i, \ldots) &\to& (\ldots, g\circ f_{i-1}, f_i\circ g^{-1}, \ldots),
   102 \end{eqnarray*}
   106 \end{eqnarray*}
   103 leaving the $M_i$ and $N_i$ fixed.
   107 leaving the $M_i$ and $N_i$ fixed.
   104 (Keep in mind the case $R'_i = R_i$.)
   108 (Keep in mind the case $R'_i = R_i$.)
   105 (See Figure xxxx.)
   109 (See Figure \ref{xdfig3}.)
       
   110 \begin{figure}[t]
       
   111 $$\mathfig{.9}{tempkw/dfig3}$$
       
   112 \caption{Conjugating by a homeomorphism}\label{xdfig3}
       
   113 \end{figure}
   106 \item If $M_i = M'_i \du M''_i$ and $N_i = N'_i \du N''_i$ (and there is a
   114 \item If $M_i = M'_i \du M''_i$ and $N_i = N'_i \du N''_i$ (and there is a
   107 compatible disjoint union of $\bd M = \bd N$), we can replace
   115 compatible disjoint union of $\bd M = \bd N$), we can replace
   108 \begin{eqnarray*}
   116 \begin{eqnarray*}
   109 	(\ldots, M_{i-1}, M_i, M_{i+1}, \ldots) &\to& (\ldots, M_{i-1}, M'_i, M''_i, M_{i+1}, \ldots) \\
   117 	(\ldots, M_{i-1}, M_i, M_{i+1}, \ldots) &\to& (\ldots, M_{i-1}, M'_i, M''_i, M_{i+1}, \ldots) \\
   110 	(\ldots, N_{i-1}, N_i, N_{i+1}, \ldots) &\to& (\ldots, N_{i-1}, N'_i, N''_i, N_{i+1}, \ldots) \\
   118 	(\ldots, N_{i-1}, N_i, N_{i+1}, \ldots) &\to& (\ldots, N_{i-1}, N'_i, N''_i, N_{i+1}, \ldots) \\
   111 	(\ldots, R_{i-1}, R_i, R_{i+1}, \ldots) &\to& 
   119 	(\ldots, R_{i-1}, R_i, R_{i+1}, \ldots) &\to& 
   112 						(\ldots, R_{i-1}, R_i\cup M''_i, R_i\cup N'_i, R_{i+1}, \ldots) \\
   120 						(\ldots, R_{i-1}, R_i\cup M''_i, R_i\cup N'_i, R_{i+1}, \ldots) \\
   113 	(\ldots, f_{i-1}, f_i, \ldots) &\to& (\ldots, f_{i-1}, \rm{id}, f_i, \ldots) .
   121 	(\ldots, f_{i-1}, f_i, \ldots) &\to& (\ldots, f_{i-1}, \rm{id}, f_i, \ldots) .
   114 \end{eqnarray*}
   122 \end{eqnarray*}
   115 (See Figure xxxx.)
   123 (See Figure \ref{xdfig1}.)
       
   124 \begin{figure}[t]
       
   125 $$\mathfig{.9}{tempkw/dfig1}$$
       
   126 \caption{Changing the order of a surgery}\label{xdfig1}
       
   127 \end{figure}
   116 \end{itemize}
   128 \end{itemize}
   117 
   129 
   118 Note that the second equivalence increases the number of holes (or arity) by 1.
   130 Note that the second equivalence increases the number of holes (or arity) by 1.
   119 We can make a similar identification with the roles of $M'_i$ and $M''_i$ reversed.
   131 We can make a similar identification with the roles of $M'_i$ and $M''_i$ reversed.
   120 In terms of the ``sequence of surgeries" picture, this says that if two successive surgeries
   132 In terms of the ``sequence of surgeries" picture, this says that if two successive surgeries