diff -r ead6bc1a703f -r 2625a6f51684 blob1.tex --- a/blob1.tex Thu Nov 20 21:08:30 2008 +0000 +++ b/blob1.tex Tue Feb 03 21:06:04 2009 +0000 @@ -255,6 +255,8 @@ $c\times I \in \cC(Y\times I)$; ... \nn{should eventually include full details of definition of fields.} +\input{text/fields.tex} + \nn{note: probably will suppress from notation the distinction between fields and their (orientation-reversal) duals} @@ -939,477 +941,9 @@ \nn{say something about associativity here} -\section{Gluing} -\label{sec:gluing}% - -We now turn to establishing the gluing formula for blob homology, restated from Property \ref{property:gluing} in the Introduction -\begin{itemize} -%\mbox{}% <-- gets the indenting right -\item For any $(n-1)$-manifold $Y$, the blob homology of $Y \times I$ is -naturally an $A_\infty$ category. % We'll write $\bc_*(Y)$ for $\bc_*(Y \times I)$ below. - -\item For any $n$-manifold $X$, with $Y$ a codimension $0$-submanifold of its boundary, the blob homology of $X$ is naturally an -$A_\infty$ module for $\bc_*(Y \times I)$. - -\item For any $n$-manifold $X$, with $Y \cup Y^{\text{op}}$ a codimension -$0$-submanifold of its boundary, the blob homology of $X'$, obtained from -$X$ by gluing along $Y$, is the $A_\infty$ self-tensor product of -$\bc_*(X)$ as an $\bc_*(Y \times I)$-bimodule. -\begin{equation*} -\bc_*(X') \iso \bc_*(X) \Tensor^{A_\infty}_{\mathclap{\bc_*(Y \times I)}} \!\!\!\!\!\!\xymatrix{ \ar@(ru,rd)@<-1ex>[]} -\end{equation*} -\end{itemize} - -Although this gluing formula is stated in terms of $A_\infty$ categories and their (bi-)modules, it will be more natural for us to give alternative -definitions of `topological' $A_\infty$-categories and their bimodules, explain how to translate between the `algebraic' and `topological' definitions, -and then prove the gluing formula in the topological langauge. Section \ref{sec:topological-A-infty} below explains these definitions, and establishes -the desired equivalence. This is quite involved, and in particular requires us to generalise the definition of blob homology to allow $A_\infty$ algebras -as inputs, and to re-establish many of the properties of blob homology in this generality. Many readers may prefer to read the -Definitions \ref{defn:topological-algebra} and \ref{defn:topological-module} of `topological' $A_\infty$-categories, and Definition \ref{???} of the -self-tensor product of a `topological' $A_\infty$-bimodule, then skip to \S \ref{sec:boundary-action} and \S \ref{sec:gluing-formula} for the proofs -of the gluing formula in the topological context. - -\subsection{`Topological' $A_\infty$ $n$-categories} -\label{sec:topological-A-infty}% - -This section prepares the ground for establishing Property \ref{property:gluing} by defining the notion of a \emph{topological $A_\infty$-$n$-category}. -The main result of this section is - -\begin{thm} -Topological $A_\infty$-$1$-categories are equivalent to the usual notion of -$A_\infty$-$1$-categories. -\end{thm} - -Before proving this theorem, we embark upon a long string of definitions. -For expository purposes, we begin with the $n=1$ special cases,\scott{Why are we treating the $n>1$ cases at all?} and define -first topological $A_\infty$-algebras, then topological $A_\infty$-categories, and then topological $A_\infty$-modules over these. We then turn -to the general $n$ case, defining topological $A_\infty$-$n$-categories and their modules. -\nn{Something about duals?} -\todo{Explain that we're not making contact with any previous notions for the general $n$ case?} -\kevin{probably we should say something about the relation -to [framed] $E_\infty$ algebras -} - -\todo{} -Various citations we might want to make: -\begin{itemize} -\item \cite{MR2061854} McClure and Smith's review article -\item \cite{MR0420610} May, (inter alia, definition of $E_\infty$ operad) -\item \cite{MR0236922,MR0420609} Boardman and Vogt -\item \cite{MR1256989} definition of framed little-discs operad -\end{itemize} - -\begin{defn} -\label{defn:topological-algebra}% -A ``topological $A_\infty$-algebra'' $A$ consists of the following data. -\begin{enumerate} -\item For each $1$-manifold $J$ diffeomorphic to the standard interval -$I=\left[0,1\right]$, a complex of vector spaces $A(J)$. -% either roll functoriality into the evaluation map -\item For each pair of intervals $J,J'$ an `evaluation' chain map -$\ev_{J \to J'} : \CD{J \to J'} \tensor A(J) \to A(J')$. -\item For each decomposition of intervals $J = J'\cup J''$, -a gluing map $\gl_{J',J''} : A(J') \tensor A(J'') \to A(J)$. -% or do it as two separate pieces of data -%\item along with an `evaluation' chain map $\ev_J : \CD{J} \tensor A(J) \to A(J)$, -%\item for each diffeomorphism $\phi : J \to J'$, an isomorphism $A(\phi) : A(J) \isoto A(J')$, -%\item and for each pair of intervals $J,J'$ a gluing map $\gl_{J,J'} : A(J) \tensor A(J') \to A(J \cup J')$, -\end{enumerate} -This data is required to satisfy the following conditions. -\begin{itemize} -\item The evaluation chain map is associative, in that the diagram -\begin{equation*} -\xymatrix{ - & \quad \mathclap{\CD{J' \to J''} \tensor \CD{J \to J'} \tensor A(J)} \quad \ar[dr]^{\id \tensor \ev_{J \to J'}} \ar[dl]_{\compose \tensor \id} & \\ -\CD{J' \to J''} \tensor A(J') \ar[dr]^{\ev_{J' \to J''}} & & \CD{J \to J''} \tensor A(J) \ar[dl]_{\ev_{J \to J''}} \\ - & A(J'') & -} -\end{equation*} -commutes up to homotopy. -Here the map $$\compose : \CD{J' \to J''} \tensor \CD{J \to J'} \to \CD{J \to J''}$$ is a composition: take products of singular chains first, then compose diffeomorphisms. -%% or the version for separate pieces of data: -%\item If $\phi$ is a diffeomorphism from $J$ to itself, the maps $\ev_J(\phi, -)$ and $A(\phi)$ are the same. -%\item The evaluation chain map is associative, in that the diagram -%\begin{equation*} -%\xymatrix{ -%\CD{J} \tensor \CD{J} \tensor A(J) \ar[r]^{\id \tensor \ev_J} \ar[d]_{\compose \tensor \id} & -%\CD{J} \tensor A(J) \ar[d]^{\ev_J} \\ -%\CD{J} \tensor A(J) \ar[r]_{\ev_J} & -%A(J) -%} -%\end{equation*} -%commutes. (Here the map $\compose : \CD{J} \tensor \CD{J} \to \CD{J}$ is a composition: take products of singular chains first, then use the group multiplication in $\Diff(J)$.) -\item The gluing maps are \emph{strictly} associative. That is, given $J$, $J'$ and $J''$, the diagram -\begin{equation*} -\xymatrix{ -A(J) \tensor A(J') \tensor A(J'') \ar[rr]^{\gl_{J,J'} \tensor \id} \ar[d]_{\id \tensor \gl_{J',J''}} && -A(J \cup J') \tensor A(J'') \ar[d]^{\gl_{J \cup J', J''}} \\ -A(J) \tensor A(J' \cup J'') \ar[rr]_{\gl_{J, J' \cup J''}} && -A(J \cup J' \cup J'') -} -\end{equation*} -commutes. -\item The gluing and evaluation maps are compatible. -\nn{give diagram, or just say ``in the obvious way", or refer to diagram in blob eval map section?} -\end{itemize} -\end{defn} - -\begin{rem} -We can restrict the evaluation map to $0$-chains, and see that $J \mapsto A(J)$ and $(\phi:J \to J') \mapsto \ev_{J \to J'}(\phi, \bullet)$ together -constitute a functor from the category of intervals and diffeomorphisms between them to the category of complexes of vector spaces. -Further, once this functor has been specified, we only need to know how the evaluation map acts when $J = J'$. -\end{rem} - -%% if we do things separately, we should say this: -%\begin{rem} -%Of course, the first and third pieces of data (the complexes, and the isomorphisms) together just constitute a functor from the category of -%intervals and diffeomorphisms between them to the category of complexes of vector spaces. -%Further, one can combine the second and third pieces of data, asking instead for a map -%\begin{equation*} -%\ev_{J,J'} : \CD{J \to J'} \tensor A(J) \to A(J'). -%\end{equation*} -%(Any $k$-parameter family of diffeomorphisms in $C_k(\Diff(J \to J'))$ factors into a single diffeomorphism $J \to J'$ and a $k$-parameter family of -%diffeomorphisms in $\CD{J'}$.) -%\end{rem} - -To generalise the definition to that of a category, we simply introduce a set of objects which we call $A(pt)$. Now we associate complexes to each -interval with boundary conditions $(J, c_-, c_+)$, with $c_-, c_+ \in A(pt)$, and only ask for gluing maps when the boundary conditions match up: -\begin{equation*} -\gl : A(J, c_-, c_0) \tensor A(J', c_0, c_+) \to A(J \cup J', c_-, c_+). -\end{equation*} -The action of diffeomorphisms (and of $k$-parameter families of diffeomorphisms) ignores the boundary conditions. -\todo{we presumably need to say something about $\id_c \in A(J, c, c)$.} - -At this point we can give two motivating examples. The first is `chains of maps to $M$' for some fixed target space $M$. -\begin{defn} -Define the topological $A_\infty$ category $C_*(\Maps(\bullet \to M))$ by -\begin{enumerate} -\item $A(J) = C_*(\Maps(J \to M))$, singular chains on the space of smooth maps from $J$ to $M$, -\item $\ev_{J,J'} : \CD{J \to J'} \tensor A(J) \to A(J')$ is the composition -\begin{align*} -\CD{J \to J'} \tensor C_*(\Maps(J \to M)) & \to C_*(\Diff(J \to J') \times \Maps(J \to M)) \\ & \to C_*(\Maps(J' \to M)), -\end{align*} -where the first map is the product of singular chains, and the second is precomposition by the inverse of a diffeomorphism, -\item $\gl_{J,J'} : A(J) \tensor A(J')$ takes the product of singular chains, then glues maps to $M$ together. -\end{enumerate} -The associativity conditions are trivially satisfied. -\end{defn} - -The second example is simply the blob complex of $Y \times J$, for any $n-1$ manifold $Y$. We define $A(J) = \bc_*(Y \times J)$. -Observe $\Diff(J \to J')$ embeds into $\Diff(Y \times J \to Y \times J')$. The evaluation and gluing maps then come directly from Properties -\ref{property:evaluation} and \ref{property:gluing-map} respectively. We'll often write $bc_*(Y)$ for this algebra. - -The definition of a module follows closely the definition of an algebra or category. -\begin{defn} -\label{defn:topological-module}% -A topological $A_\infty$-(left-)module $M$ over a topological $A_\infty$ category $A$ -consists of the following data. -\begin{enumerate} -\item A functor $K \mapsto M(K)$ from $1$-manifolds diffeomorphic to the standard interval, with the upper boundary point `marked', to complexes of vector spaces. -\item For each pair of such marked intervals, -an `evaluation' chain map $\ev_{K\to K'} : \CD{K \to K'} \tensor M(K) \to M(K')$. -\item For each decomposition $K = J\cup K'$ of the marked interval -$K$ into an unmarked interval $J$ and a marked interval $K'$, a gluing map -$\gl_{J,K'} : A(J) \tensor M(K') \to M(K)$. -\end{enumerate} -The above data is required to satisfy -conditions analogous to those in Definition \ref{defn:topological-algebra}. -\end{defn} - -For any manifold $X$ with $\bdy X = Y$ (or indeed just with $Y$ a codimension $0$-submanifold of $\bdy X$) we can think of $\bc_*(X)$ as -a topological $A_\infty$ module over $\bc_*(Y)$, the topological $A_\infty$ category described above. -For each interval $K$, we have $M(K) = \bc_*((Y \times K) \cup_Y X)$. -(Here we glue $Y \times pt$ to $Y \subset \bdy X$, where $pt$ is the marked point of $K$.) Again, the evaluation and gluing maps come directly from Properties -\ref{property:evaluation} and \ref{property:gluing-map} respectively. - -The definition of a bimodule is like the definition of a module, -except that we have two disjoint marked intervals $K$ and $L$, one with a marked point -on the upper boundary and the other with a marked point on the lower boundary. -There are evaluation maps corresponding to gluing unmarked intervals -to the unmarked ends of $K$ and $L$. - -Let $X$ be an $n$-manifold with a copy of $Y \du -Y$ embedded as a -codimension-0 submanifold of $\bdy X$. -Then the the assignment $K,L \mapsto \bc_*(X \cup_Y (Y\times K) \cup_{-Y} (-Y\times L))$ has the -structure of a topological $A_\infty$ bimodule over $\bc_*(Y)$. - -Next we define the coend -(or gluing or tensor product or self tensor product, depending on the context) -$\gl(M)$ of a topological $A_\infty$ bimodule $M$. This will be an `initial' or `universal' object satisfying various properties. -\begin{defn} -We define a category $\cG(M)$. Objects consist of the following data. -\begin{itemize} -\item For each interval $N$ with both endpoints marked, a complex of vector spaces C(N). -\item For each pair of intervals $N,N'$ an evaluation chain map -$\ev_{N \to N'} : \CD{N \to N'} \tensor C(N) \to C(N')$. -\item For each decomposition of intervals $N = K\cup L$, -a gluing map $\gl_{K,L} : M(K,L) \to C(N)$. -\end{itemize} -This data must satisfy the following conditions. -\begin{itemize} -\item The evaluation maps are associative. -\nn{up to homotopy?} -\item Gluing is strictly associative. -That is, given a decomposition $N = K\cup J\cup L$, the chain maps associated to -$K\du J\du L \to (K\cup J)\du L \to N$ and $K\du J\du L \to K\du (J\cup L) \to N$ -agree. -\item the gluing and evaluation maps are compatible. -\end{itemize} - -A morphism $f$ between such objects $C$ and $C'$ is a chain map $f_N : C(N) \to C'(N)$ for each interval $N$ with both endpoints marked, -satisfying the following conditions. -\begin{itemize} -\item For each pair of intervals $N,N'$, the diagram -\begin{equation*} -\xymatrix{ -\CD{N \to N'} \tensor C(N) \ar[d]_{\ev} \ar[r]^{\id \tensor f_N} & \CD{N \to N'} \tensor C'(N) \ar[d]^{\ev} \\ -C(N) \ar[r]_{f_N} & C'(N) -} -\end{equation*} -commutes. -\item For each decomposition of intervals $N = K \cup L$, the gluing map for $C'$, $\gl'_{K,L} : M(K,L) \to C'(N)$ is the composition -$$M(K,L) \xto{\gl_{K,L}} C(N) \xto{f_N} C'(N).$$ -\end{itemize} -\end{defn} +\input{text/A-infty.tex} -We now define $\gl(M)$ to be an initial object in the category $\cG{M}$. This just says that for any other object $C'$ in $\cG{M}$, -there are chain maps $f_N: \gl(M)(N) \to C'(N)$, compatible with the action of families of diffeomorphisms, so that the gluing maps $M(K,L) \to C'(N)$ -factor through the gluing maps for $\gl(M)$. - -We return to our two favourite examples. First, the coend of the topological $A_\infty$ category $C_*(\Maps(\bullet \to M))$ as a bimodule over itself -is essentially $C_*(\Maps(S^1 \to M))$. \todo{} - -For the second example, given $X$ and $Y\du -Y \sub \bdy X$, the assignment -$$N \mapsto \bc_*(X \cup_{Y\du -Y} (N\times Y))$$ clearly gives an object in $\cG{M}$. -Showing that it is an initial object is the content of the gluing theorem proved below. - -The definitions for a topological $A_\infty$-$n$-category are very similar to the above -$n=1$ case. -One replaces intervals with manifolds diffeomorphic to the ball $B^n$. -Marked points are replaced by copies of $B^{n-1}$ in $\bdy B^n$. - -\nn{give examples: $A(J^n) = \bc_*(Z\times J)$ and $A(J^n) = C_*(\Maps(J \to M))$.} - -\todo{the motivating example $C_*(\maps(X, M))$} - - - -\newcommand{\skel}[1]{\operatorname{skeleton}(#1)} - -Given a topological $A_\infty$-category $\cC$, we can construct an `algebraic' $A_\infty$ category $\skel{\cC}$. First, pick your -favorite diffeomorphism $\phi: I \cup I \to I$. -\begin{defn} -We'll write $\skel{\cC} = (A, m_k)$. Define $A = \cC(I)$, and $m_2 : A \tensor A \to A$ by -\begin{equation*} -m_2 \cC(I) \tensor \cC(I) \xrightarrow{\gl_{I,I}} \cC(I \cup I) \xrightarrow{\cC(\phi)} \cC(I). -\end{equation*} -Next, we define all the `higher associators' $m_k$ by -\todo{} -\end{defn} - -Give an `algebraic' $A_\infty$ category $(A, m_k)$, we can construct a topological $A_\infty$-category, which we call $\bc_*^A$. You should -think of this as a generalisation of the blob complex, although the construction we give will \emph{not} specialise to exactly the usual definition -in the case the $A$ is actually an associative category. - -We'll first define $\cT_{k,n}$ to be the set of planar forests consisting of $n-k$ trees, with a total of $n$ leaves. Thus -\todo{$\cT_{0,n}$ has 1 element, with $n$ vertical lines, $\cT_{1,n}$ has $n-1$ elements, each with a single trivalent vertex, $\cT_{2,n}$ etc...} -\begin{align*} -\end{align*} - -\begin{defn} -The topological $A_\infty$ category $\bc_*^A$ is doubly graded, by `blob degree' and `internal degree'. We'll write $\bc_k^A$ for the blob degree $k$ piece. -The homological degree of an element $a \in \bc_*^A(J)$ -is the sum of the blob degree and the internal degree. - -We first define $\bc_0^A(J)$ as a vector space by -\begin{equation*} -\bc_0^A(J) = \DirectSum_{\substack{\{J_i\}_{i=1}^n \\ \mathclap{\bigcup_i J_i = J}}} \Tensor_{i=1}^n (\CD{J_i \to I} \tensor A). -\end{equation*} -(That is, for each division of $J$ into finitely many subintervals, -we have the tensor product of chains of diffeomorphisms from each subinterval to the standard interval, -and a copy of $A$ for each subinterval.) -The internal degree of an element $(f_1 \tensor a_1, \ldots, f_n \tensor a_n)$ is the sum of the dimensions of the singular chains -plus the sum of the homological degrees of the elements of $A$. -The differential is defined just by the graded Leibniz rule and the differentials on $\CD{J_i \to I}$ and on $A$. - -Next, -\begin{equation*} -\bc_1^A(J) = \DirectSum_{\substack{\{J_i\}_{i=1}^n \\ \mathclap{\bigcup_i J_i = J}}} \DirectSum_{T \in \cT_{1,n}} \Tensor_{i=1}^n (\CD{J_i \to I} \tensor A). -\end{equation*} -\end{defn} - -\begin{figure}[!ht] -\begin{equation*} -\mathfig{0.7}{associahedron/A4-vertices} -\end{equation*} -\caption{The vertices of the $k$-dimensional associahedron are indexed by binary trees on $k+2$ leaves.} -\label{fig:A4-vertices} -\end{figure} - -\begin{figure}[!ht] -\begin{equation*} -\mathfig{0.7}{associahedron/A4-faces} -\end{equation*} -\caption{The faces of the $k$-dimensional associahedron are indexed by trees with $2$ vertices on $k+2$ leaves.} -\label{fig:A4-vertices} -\end{figure} - -\newcommand{\tm}{\widetilde{m}} - -Let $\tm_1(a) = a$. - -We now define $\bdy(\tm_k(a_1 \tensor \cdots \tensor a_k))$, first giving an opaque formula, then explaining the combinatorics behind it. -\begin{align} -\notag \bdy(\tm_k(a_1 & \tensor \cdots \tensor a_k)) = \\ -\label{eq:bdy-tm-k-1} & \phantom{+} \sum_{\ell'=0}^{k-1} (-1)^{\abs{\tm_k}+\sum_{j=1}^{\ell'} \abs{a_j}} \tm_k(a_1 \tensor \cdots \tensor \bdy a_{\ell'+1} \tensor \cdots \tensor a_k) + \\ -\label{eq:bdy-tm-k-2} & + \sum_{\ell=1}^{k-1} \tm_{\ell}(a_1 \tensor \cdots \tensor a_{\ell}) \tensor \tm_{k-\ell}(a_{\ell+1} \tensor \cdots \tensor a_k) + \\ -\label{eq:bdy-tm-k-3} & + \sum_{\ell=1}^{k-1} \sum_{\ell'=0}^{l-1} (-1)^{\abs{\tm_k}+\sum_{j=1}^{\ell'} \abs{a_j}} \tm_{\ell}(a_1 \tensor \cdots \tensor m_{k-\ell + 1}(a_{\ell' + 1} \tensor \cdots \tensor a_{\ell' + k - \ell + 1}) \tensor \cdots \tensor a_k) -\end{align} -The first set of terms in $\bdy(\tm_k(a_1 \tensor \cdots \tensor a_k))$ just have $\bdy$ acting on each argument $a_i$. -The terms appearing in \eqref{eq:bdy-tm-k-2} and \eqref{eq:bdy-tm-k-3} are indexed by trees with $2$ vertices on $k+1$ leaves. -Note here that we have one more leaf than there arguments of $\tm_k$. -(See Figure \ref{fig:A4-vertices}, in which the rightmost branches are helpfully drawn in red.) -We will treat the vertices which involve a rightmost (red) branch differently from the vertices which only involve the first $k$ leaves. -The terms in \eqref{eq:bdy-tm-k-2} arise in the cases in which both -vertices are rightmost, and the corresponding term in $\bdy(\tm_k(a_1 \tensor \cdots \tensor a_k))$ is a tensor product of the form -$$\tm_{\ell}(a_1 \tensor \cdots \tensor a_{\ell}) \tensor \tm_{k-\ell}(a_{\ell+1} \tensor \cdots \tensor a_k)$$ -where $\ell + 1$ and $k - \ell + 1$ are the number of branches entering the vertices. -If only one vertex is rightmost, we get the term $$\tm_{\ell}(a_1 \tensor \cdots \tensor m_{k-\ell+1}(a_{\ell' + 1} \tensor \cdots \tensor a_{\ell' + k - \ell}) \tensor \cdots \tensor a_k)$$ -in \eqref{eq:bdy-tm-k-3}, -where again $\ell + 1$ is the number of branches entering the rightmost vertex, $k-\ell+1$ is the number of branches entering the other vertex, and $\ell'$ is the number of edges meeting the rightmost vertex which start to the left of the other vertex. -For example, we have -\begin{align*} -\bdy(\tm_2(a \tensor b)) & = \left(\tm_2(\bdy a \tensor b) + (-1)^{\abs{a}} \tm_2(a \tensor \bdy b)\right) + \\ - & \qquad - a \tensor b + m_2(a \tensor b) \\ -\bdy(\tm_3(a \tensor b \tensor c)) & = \left(- \tm_3(\bdy a \tensor b \tensor c) + (-1)^{\abs{a} + 1} \tm_3(a \tensor \bdy b \tensor c) + (-1)^{\abs{a} + \abs{b} + 1} \tm_3(a \tensor b \tensor \bdy c)\right) + \\ - & \qquad + \left(- \tm_2(a \tensor b) \tensor c + a \tensor \tm_2(b \tensor c)\right) + \\ - & \qquad + \left(- \tm_2(m_2(a \tensor b) \tensor c) + \tm_2(a, m_2(b \tensor c)) + m_3(a \tensor b \tensor c)\right) -\end{align*} -\begin{align*} -\bdy(& \tm_4(a \tensor b \tensor c \tensor d)) = \left(\tm_4(\bdy a \tensor b \tensor c \tensor d) + \cdots + \tm_4(a \tensor b \tensor c \tensor \bdy d)\right) + \\ - & + \left(\tm_3(a \tensor b \tensor c) \tensor d + \tm_2(a \tensor b) \tensor \tm_2(c \tensor d) + a \tensor \tm_3(b \tensor c \tensor d)\right) + \\ - & + \left(\tm_3(m_2(a \tensor b) \tensor c \tensor d) + \tm_3(a \tensor m_2(b \tensor c) \tensor d) + \tm_3(a \tensor b \tensor m_2(c \tensor d))\right. + \\ - & + \left.\tm_2(m_3(a \tensor b \tensor c) \tensor d) + \tm_2(a \tensor m_3(b \tensor c \tensor d)) + m_4(a \tensor b \tensor c \tensor d)\right) \\ -\end{align*} -See Figure \ref{fig:A4-terms}, comparing it against Figure \ref{fig:A4-faces}, to see this illustrated in the case $k=4$. There the $3$ faces closest -to the top of the diagram have two rightmost vertices, while the other $6$ faces have only one. - -\begin{figure}[!ht] -\begin{equation*} -\mathfig{1.0}{associahedron/A4-terms} -\end{equation*} -\caption{The terms of $\bdy(\tm_k(a_1 \tensor \cdots \tensor a_k))$ correspond to the faces of the $k-1$ dimensional associahedron.} -\label{fig:A4-terms} -\end{figure} - -\begin{lem} -This definition actually results in a chain complex, that is $\bdy^2 = 0$. -\end{lem} -\begin{proof} -\newcommand{\T}{\text{---}} -\newcommand{\ssum}[1]{{\sum}^{(#1)}} -For the duration of this proof, inside a summation over variables $l_1, \ldots, l_m$, an expression with $m$ dashes will be interpreted -by replacing each dash with contiguous factors from $a_1 \tensor \cdots \tensor a_k$, so the first dash takes the first $l_1$ factors, the second -takes the next $l_2$ factors, and so on. Further, we'll write $\ssum{m}$ for $\sum_{\sum_{i=1}^m l_i = k}$. -In this notation, the formula for the differential becomes -\begin{align} -\notag -\bdy \tm(\T) & = \ssum{2} \tm(\T) \tensor \tm(\T) \times \sigma_{0;l_1,l_2} + \ssum{3} \tm(\T \tensor m(\T) \tensor \T) \times \tau_{0;l_1,l_2,l_3} \\ -\intertext{and we calculate} -\notag -\bdy^2 \tm(\T) & = \ssum{2} \bdy \tm(\T) \tensor \tm(\T) \times \sigma_{0;l_1,l_2} \\ -\notag & \qquad + \ssum{2} \tm(\T) \tensor \bdy \tm(\T) \times \sigma_{0;l_1,l_2} \\ -\notag & \qquad + \ssum{3} \bdy \tm(\T \tensor m(\T) \tensor \T) \times \tau_{0;l_1,l_2,l_3} \\ -\label{eq:d21} & = \ssum{3} \tm(\T) \tensor \tm(\T) \tensor \tm(\T) \times \sigma_{0;l_1+l_2,l_3} \sigma_{0;l_1,l_2} \\ -\label{eq:d22} & \qquad + \ssum{4} \tm(\T \tensor m(\T) \tensor \T) \tensor \tm(\T) \times \sigma_{0;l_1+l_2+l_3,l_4} \tau_{0;l_1,l_2,l_3} \\ -\label{eq:d23} & \qquad + \ssum{3} \tm(\T) \tensor \tm(\T) \tensor \tm(\T) \times \sigma_{0;l_1,l_2+l_3} \sigma_{l_1;l_2,l_3} \\ -\label{eq:d24} & \qquad + \ssum{4} \tm(\T) \tensor \tm(\T \tensor m(\T) \tensor \T) \times \sigma_{0;l_1,l_2+l_3+l_4} \tau_{l_1;l_2,l_3,l_4} \\ -\label{eq:d25} & \qquad + \ssum{4} \tm(\T \tensor m(\T) \tensor \T) \tensor \tm(\T) \times \tau_{0;l_1,l_2,l_3+l_4} ??? \\ -\label{eq:d26} & \qquad + \ssum{4} \tm(\T) \tensor \tm(\T \tensor m(\T) \tensor \T) \times \tau_{0;l_1+l_2,l_3,l_4} \sigma_{0;l_1,l_2} \\ -\label{eq:d27} & \qquad + \ssum{5} \tm(\T \tensor m(\T) \tensor \T \tensor m(\T) \tensor \T) \times \tau_{0;l_1+l_2+l_3,l_4,l_5} \tau_{0;l_1,l_2,l_3} \\ -\label{eq:d28} & \qquad + \ssum{5} \tm(\T \tensor m(\T \tensor m(\T) \tensor \T) \tensor \T) \times \tau_{0;l_1,l_2+l_3+l_4,l_5} ??? \\ -\label{eq:d29} & \qquad + \ssum{5} \tm(\T \tensor m(\T) \tensor \T \tensor m(\T) \tensor \T) \times \tau_{0;l_1,l_2,l_3+l_4+l_5} ??? -\end{align} -Now, we see the the expressions on the right hand side of line \eqref{eq:d21} and those on \eqref{eq:d23} cancel. Similarly, line \eqref{eq:d22} cancels -with \eqref{eq:d25}, \eqref{eq:d24} with \eqref{eq:d26}, and \eqref{eq:d27} with \eqref{eq:d29}. Finally, we need to see that \eqref{eq:d28} gives $0$, -by the usual relations between the $m_k$ in an $A_\infty$ algebra. -\end{proof} - -\nn{Need to let the input $n$-category $C$ be a graded thing (e.g. DG -$n$-category or $A_\infty$ $n$-category). DG $n$-category case is pretty -easy, I think, so maybe it should be done earlier??} - -\bigskip - -Outline: -\begin{itemize} -\item recall defs of $A_\infty$ category (1-category only), modules, (self-) tensor product. -use graphical/tree point of view, rather than following Keller exactly -\item define blob complex in $A_\infty$ case; fat mapping cones? tree decoration? -\item topological $A_\infty$ cat def (maybe this should go first); also modules gluing -\item motivating example: $C_*(\maps(X, M))$ -\item maybe incorporate dual point of view (for $n=1$), where points get -object labels and intervals get 1-morphism labels -\end{itemize} - - -\subsection{$A_\infty$ action on the boundary} -\label{sec:boundary-action}% -Let $Y$ be an $n{-}1$-manifold. -The collection of complexes $\{\bc_*(Y\times I; a, b)\}$, where $a, b \in \cC(Y)$ are boundary -conditions on $\bd(Y\times I) = Y\times \{0\} \cup Y\times\{1\}$, has the structure -of an $A_\infty$ category. - -Composition of morphisms (multiplication) depends of a choice of homeomorphism -$I\cup I \cong I$. Given this choice, gluing gives a map -\eq{ - \bc_*(Y\times I; a, b) \otimes \bc_*(Y\times I; b, c) \to \bc_*(Y\times (I\cup I); a, c) - \cong \bc_*(Y\times I; a, c) -} -Using (\ref{CDprop}) and the inclusion $\Diff(I) \sub \Diff(Y\times I)$ gives the various -higher associators of the $A_\infty$ structure, more or less canonically. - -\nn{is this obvious? does more need to be said?} - -Let $\cA(Y)$ denote the $A_\infty$ category $\bc_*(Y\times I; \cdot, \cdot)$. - -Similarly, if $Y \sub \bd X$, a choice of collaring homeomorphism -$(Y\times I) \cup_Y X \cong X$ gives the collection of complexes $\bc_*(X; r, a)$ -(variable $a \in \cC(Y)$; fixed $r \in \cC(\bd X \setmin Y)$) the structure of a representation of the -$A_\infty$ category $\{\bc_*(Y\times I; \cdot, \cdot)\}$. -Again the higher associators come from the action of $\Diff(I)$ on a collar neighborhood -of $Y$ in $X$. - -In the next section we use the above $A_\infty$ actions to state and prove -a gluing theorem for the blob complexes of $n$-manifolds. - - -\subsection{The gluing formula} -\label{sec:gluing-formula}% -Let $Y$ be an $n{-}1$-manifold and let $X$ be an $n$-manifold with a copy -of $Y \du -Y$ contained in its boundary. -Gluing the two copies of $Y$ together we obtain a new $n$-manifold $X\sgl$. -We wish to describe the blob complex of $X\sgl$ in terms of the blob complex -of $X$. -More precisely, we want to describe $\bc_*(X\sgl; c\sgl)$, -where $c\sgl \in \cC(\bd X\sgl)$, -in terms of the collection $\{\bc_*(X; c, \cdot, \cdot)\}$, thought of as a representation -of the $A_\infty$ category $\cA(Y\du-Y) \cong \cA(Y)\times \cA(Y)\op$. - -\begin{thm} -$\bc_*(X\sgl; c\sgl)$ is quasi-isomorphic to the the self tensor product -of $\{\bc_*(X; c, \cdot, \cdot)\}$ over $\cA(Y)$. -\end{thm} - -The proof will occupy the remainder of this section. - -\nn{...} - -\bigskip - -\nn{need to define/recall def of (self) tensor product over an $A_\infty$ category} - - +\input{text/gluing.tex} @@ -1775,6 +1309,7 @@ \input{text/explicit.tex} +\input{text/obsolete.tex} % ---------------------------------------------------------------- %\newcommand{\urlprefix}{}