diff -r c5a35886cd82 -r 93ce0ba3d2d7 text/hochschild.tex --- a/text/hochschild.tex Mon Jul 12 17:29:25 2010 -0600 +++ b/text/hochschild.tex Wed Jul 14 11:06:11 2010 -0600 @@ -19,7 +19,7 @@ to find a more ``local" description of the Hochschild complex. Let $C$ be a *-1-category. -Then specializing the definitions from above to the case $n=1$ we have: +Then specializing the definition of the associated system of fields from \S \ref{sec:example:traditional-n-categories(fields)} above to the case $n=1$ we have: \begin{itemize} \item $\cC(pt) = \ob(C)$ . \item Let $R$ be a 1-manifold and $c \in \cC(\bd R)$. @@ -44,8 +44,7 @@ In order to prove this we will need to extend the definition of the blob complex to allow points to also be labeled by elements of $C$-$C$-bimodules. -(See Subsections \ref{moddecss} and \ref{ssec:spherecat} for a more general (i.e.\ $n>1$) -version of this construction.) +(See Subsections \ref{moddecss} and \ref{ssec:spherecat} for a more general version of this construction that applies in all dimensions.) Fix points $p_1, \ldots, p_k \in S^1$ and $C$-$C$-bimodules $M_1, \ldots M_k$. We define a blob-like complex $K_*(S^1, (p_i), (M_i))$. @@ -79,8 +78,8 @@ The complex $K_*(C)$ (here $C$ is being thought of as a $C$-$C$-bimodule, not a category) is homotopy equivalent to the blob complex $\bc_*(S^1; C)$. -(Proof later.) \end{lem} +The proof appears below. Next, we show that for any $C$-$C$-bimodule $M$, \begin{prop} \label{prop:hoch} @@ -249,7 +248,7 @@ \[ \bd j_\ep + j_\ep \bd = \id - i \circ s . \] -\nn{need to check signs coming from blob complex differential} +(To get the signs correct here, we add $N_\ep$ as the first blob.) Since for $\ep$ small enough $L_*^\ep$ captures all of the homology of $\bc_*(S^1)$, it follows that the mapping cone of $i \circ s$ is acyclic and therefore (using the fact that @@ -288,11 +287,11 @@ such that $\sum_i a_i q_i b_i = 0$ is in the image of $\ker(C \tensor E \tensor C \to C)$ under $\hat{g}$. For each $i$, we can find $\widetilde{q_i}$ so $g(\widetilde{q_i}) = q_i$. However $\sum_i a_i \widetilde{q_i} b_i$ need not be zero. -Consider then $$\widetilde{q} = \sum_i (a_i \tensor \widetilde{q_i} \tensor b_i) - 1 \tensor (\sum_i a_i \widetilde{q_i} b_i) \tensor 1.$$ Certainly +Consider then $$\widetilde{q} = \sum_i \left(a_i \tensor \widetilde{q_i} \tensor b_i\right) - 1 \tensor \left(\sum_i a_i \widetilde{q_i} b_i\right) \tensor 1.$$ Certainly $\widetilde{q} \in \ker(C \tensor E \tensor C \to E)$. Further, \begin{align*} -\hat{g}(\widetilde{q}) & = \sum_i (a_i \tensor g(\widetilde{q_i}) \tensor b_i) - 1 \tensor (\sum_i a_i g(\widetilde{q_i}) b_i) \tensor 1 \\ +\hat{g}(\widetilde{q}) & = \sum_i \left(a_i \tensor g(\widetilde{q_i}) \tensor b_i\right) - 1 \tensor \left(\sum_i a_i g(\widetilde{q_i}\right) b_i) \tensor 1 \\ & = q - 0 \end{align*} (here we used that $g$ is a map of $C$-$C$ bimodules, and that $\sum_i a_i q_i b_i = 0$). @@ -420,13 +419,13 @@ Let $x_i$ be equal to $x$ outside of $B$, equal to $z_i$ on $B \setmin N_\ep$, and have an additional blob $N_\ep$ with label $y_i - s_\ep(y_i)$. Define $j_\ep(x) = \sum x_i$. -\nn{need to check signs coming from blob complex differential} Note that if $x \in K'_* \cap K_*^\ep$ then $j_\ep(x) \in K'_*$ also. The key property of $j_\ep$ is \eq{ \bd j_\ep + j_\ep \bd = \id - \sigma_\ep. } +(Again, to get the correct signs, $N_\ep$ must be added as the first blob.) If $j_\ep$ were defined on all of $K_*(C\otimes C)$, this would show that $\sigma_\ep$ is a homotopy inverse to the inclusion $K'_* \to K_*(C\otimes C)$. One strategy would be to try to stitch together various $j_\ep$ for progressively smaller @@ -531,12 +530,12 @@ \bd(m\otimes a) & = & ma - am \\ \bd(m\otimes a \otimes b) & = & ma\otimes b - m\otimes ab + bm \otimes a . } -In degree 0, we send $m\in M$ to the 0-blob diagram $\mathfig{0.05}{hochschild/0-chains}$; the base point +In degree 0, we send $m\in M$ to the 0-blob diagram $\mathfig{0.04}{hochschild/0-chains}$; the base point in $S^1$ is labeled by $m$ and there are no other labeled points. In degree 1, we send $m\ot a$ to the sum of two 1-blob diagrams as shown in Figure \ref{fig:hochschild-1-chains}. -\begin{figure}[t] +\begin{figure}[ht] \begin{equation*} \mathfig{0.4}{hochschild/1-chains} \end{equation*} @@ -547,19 +546,23 @@ \label{fig:hochschild-1-chains} \end{figure} -\begin{figure}[t] +\begin{figure}[ht] \begin{equation*} \mathfig{0.6}{hochschild/2-chains-0} \end{equation*} +\caption{The 0-chains in the image of $m \tensor a \tensor b$.} +\label{fig:hochschild-2-chains-0} +\end{figure} +\begin{figure}[ht] \begin{equation*} \mathfig{0.4}{hochschild/2-chains-1} \qquad \mathfig{0.4}{hochschild/2-chains-2} \end{equation*} -\caption{The 0-, 1- and 2-chains in the image of $m \tensor a \tensor b$. -Only the supports of the 1- and 2-blobs are shown.} -\label{fig:hochschild-2-chains} +\caption{The 1- and 2-chains in the image of $m \tensor a \tensor b$. +Only the supports of the blobs are shown, but see Figure \ref{fig:hochschild-example-2-cell} for an example of a $2$-cell label.} +\label{fig:hochschild-2-chains-12} \end{figure} -\begin{figure}[t] +\begin{figure}[ht] \begin{equation*} A = \mathfig{0.1}{hochschild/v_1} + \mathfig{0.1}{hochschild/v_2} + \mathfig{0.1}{hochschild/v_3} + \mathfig{0.1}{hochschild/v_4} \end{equation*} @@ -567,20 +570,20 @@ v_1 & = \mathfig{0.05}{hochschild/v_1-1} - \mathfig{0.05}{hochschild/v_1-2} & v_2 & = \mathfig{0.05}{hochschild/v_2-1} - \mathfig{0.05}{hochschild/v_2-2} \\ v_3 & = \mathfig{0.05}{hochschild/v_3-1} - \mathfig{0.05}{hochschild/v_3-2} & v_4 & = \mathfig{0.05}{hochschild/v_4-1} - \mathfig{0.05}{hochschild/v_4-2} \end{align*} -\caption{One of the 2-cells from Figure \ref{fig:hochschild-2-chains}.} +\caption{One of the 2-cells from Figure \ref{fig:hochschild-2-chains-12}.} \label{fig:hochschild-example-2-cell} \end{figure} In degree 2, we send $m\ot a \ot b$ to the sum of 24 ($=6\cdot4$) 2-blob diagrams as shown in -Figure \ref{fig:hochschild-2-chains}. -In Figure \ref{fig:hochschild-2-chains} the 1- and 2-blob diagrams are indicated only by their support. +Figures \ref{fig:hochschild-2-chains-0} and \ref{fig:hochschild-2-chains-12}. +In Figure \ref{fig:hochschild-2-chains-12} the 1- and 2-blob diagrams are indicated only by their support. We leave it to the reader to determine the labels of the 1-blob diagrams. Each 2-cell in the figure is labeled by a ball $V$ in $S^1$ which contains the support of all 1-blob diagrams in its boundary. Such a 2-cell corresponds to a sum of the 2-blob diagrams obtained by adding $V$ as an outer (non-twig) blob to each of the 1-blob diagrams in the boundary of the 2-cell. Figure \ref{fig:hochschild-example-2-cell} shows this explicitly for the 2-cell -labeled $A$ in Figure \ref{fig:hochschild-2-chains}. +labeled $A$ in Figure \ref{fig:hochschild-2-chains-12}. Note that the (blob complex) boundary of this sum of 2-blob diagrams is precisely the sum of the 1-blob diagrams corresponding to the boundary of the 2-cell. (Compare with the proof of \ref{bcontract}.)