diff -r cb70a71710a5 -r 0993acb4f314 text/deligne.tex --- a/text/deligne.tex Sun Nov 01 17:02:10 2009 +0000 +++ b/text/deligne.tex Sun Nov 01 18:51:40 2009 +0000 @@ -7,6 +7,76 @@ The singular chains of the $n$-dimensional fat graph operad act on blob cochains. \end{prop} +We will give a more precise statement of the proposition below. + +\nn{for now, we just sketch the proof.} + +\def\mapinf{\Maps_\infty} + +The usual Deligne conjecture \nn{need refs} gives a map +\[ + C_*(LD_k)\otimes \overbrace{Hoch^*(C, C)\otimes\cdots\otimes Hoch^*(C, C)}^{\text{$k$ copies}} + \to Hoch^*(C, C) . +\] +Here $LD_k$ is the $k$-th space of the little disks operad, and $Hoch^*(C, C)$ denotes Hochschild +cochains. +The little disks operad is homotopy equivalent to the fat graph operad +\nn{need ref; and need to restrict which fat graphs}, and Hochschild cochains are homotopy equivalent to $A_\infty$ endomorphisms +of the blob complex of the interval. +\nn{need to make sure we prove this above}. +So the 1-dimensional Deligne conjecture can be restated as +\begin{eqnarray*} + C_*(FG_k)\otimes \mapinf(\bc^C_*(I), \bc^C_*(I))\otimes\cdots + \otimes \mapinf(\bc^C_*(I), \bc^C_*(I)) & \\ + & \hspace{-5em} \to \mapinf(\bc^C_*(I), \bc^C_*(I)) . +\end{eqnarray*} +See Figure \ref{delfig1}. +\begin{figure}[!ht] +$$\mathfig{.9}{tempkw/delfig1}$$ +\caption{A fat graph}\label{delfig1}\end{figure} + +We can think of a fat graph as encoding a sequence of surgeries, starting at the bottommost interval +of Figure \ref{delfig1} and ending at the topmost interval. +The surgeries correspond to the $k$ bigon-shaped ``holes" in the fat graph. +We remove the bottom interval of the bigon and replace it with the top interval. +To map this topological operation to an algebraic one, we need, for each hole, element of +$\mapinf(\bc^C_*(I_{\text{bottom}}), \bc^C_*(I_{\text{top}}))$. +So for each fixed fat graph we have a map +\[ + \mapinf(\bc^C_*(I), \bc^C_*(I))\otimes\cdots + \otimes \mapinf(\bc^C_*(I), \bc^C_*(I)) \to \mapinf(\bc^C_*(I), \bc^C_*(I)) . +\] +If we deform the fat graph, corresponding to a 1-chain in $C_*(FG_k)$, we get a homotopy +between the maps associated to the endpoints of the 1-chain. +Similarly, higher-dimensional chains in $C_*(FG_k)$ give rise to higher homotopies. + +It should now be clear how to generalize this to higher dimensions. +In the sequence-of-surgeries description above, we never used the fact that the manifolds +involved were 1-dimensional. +Thus we can define a $n$-dimensional fat graph to sequence of general surgeries +on an $n$-manifold. +More specifically, \nn{...} + + +\medskip +\hrule\medskip + + +Figure \ref{delfig2} +\begin{figure}[!ht] +$$\mathfig{.9}{tempkw/delfig2}$$ +\caption{A fat graph}\label{delfig2}\end{figure} + + +\begin{eqnarray*} + C_*(FG^n_{\overline{M}, \overline{N}})\otimes \mapinf(\bc_*(M_0), \bc_*(N_0))\otimes\cdots\otimes +\mapinf(\bc_*(M_{k-1}), \bc_*(N_{k-1})) & \\ + & \hspace{-5em}\to \mapinf(\bc_*(M_k), \bc_*(N_k)) +\end{eqnarray*} + +\medskip +\hrule\medskip + The $n$-dimensional fat graph operad can be thought of as a sequence of general surgeries of $n$-manifolds $R_i \cup A_i \leadsto R_i \cup B_i$ together with mapping cylinders of diffeomorphisms