some changes to blobdef, in particular indexing starts at 1 now
authorScott Morrison <scott@tqft.net>
Wed, 02 Jun 2010 11:45:19 -0700
changeset 321 76c301fdf0a2
parent 320 4b64f9c6313f
child 322 091c36b943e7
some changes to blobdef, in particular indexing starts at 1 now
blob1.tex
text/appendixes/misc_appendices.tex
text/appendixes/smallblobs.tex
text/blobdef.tex
text/hochschild.tex
--- a/blob1.tex	Wed Jun 02 08:43:12 2010 -0700
+++ b/blob1.tex	Wed Jun 02 11:45:19 2010 -0700
@@ -1,14 +1,10 @@
 \documentclass[11pt,leqno]{article}
 
-%\usepackage{amsthm}
-
 \newcommand{\pathtotrunk}{./}
 \input{text/article_preamble}
 \input{text/top_matter}
 \input{text/kw_macros}
 
-
-%\title{Blob Homology}
 \title{The Blob Complex}
 
 \begin{document}
@@ -20,12 +16,10 @@
 
 \maketitle
 
-
-[revision $\ge$ 276;  $\ge$ 30 May 2010]
+[revision $\ge$ 320;  $\ge$ 2 June 2010]
 
 \textbf{Draft version, read with caution.}
 
-
 \nn{maybe to do: add appendix on various versions of acyclic models}
 
 \paragraph{To do list}
@@ -60,7 +54,6 @@
 
 \input{text/intro}
 
-%\input{text/definitions}
 \input{text/tqftreview}
 
 \input{text/blobdef}
@@ -87,15 +80,9 @@
 
 \input{text/appendixes/comparing_defs}
 
-\input{text/appendixes/misc_appendices}
-
-%\input{text/obsolete}
-
 % ----------------------------------------------------------------
 %\newcommand{\urlprefix}{}
 \bibliographystyle{plain}
-%Included for winedt:
-%input "bibliography/bibliography.bib"
 \bibliography{bibliography/bibliography}
 % ----------------------------------------------------------------
 
@@ -103,8 +90,6 @@
 \url{http://tqft.net/blobs},
 and at \url{http://canyon23.net/math/}.
 
-% A GTART necessity:
-% \Addresses
 % ----------------------------------------------------------------
 \end{document}
 % ----------------------------------------------------------------
--- a/text/appendixes/misc_appendices.tex	Wed Jun 02 08:43:12 2010 -0700
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,30 +0,0 @@
-%!TEX root = ../../blob1.tex
-
-
-
-%\section{Morphisms and duals of topological $A_\infty$ modules}
-%\label{sec:A-infty-hom-and-duals}%
-%
-%\begin{defn}
-%If $\cM$ and $\cN$ are topological $A_\infty$ left modules over a topological $A_\infty$ category $\cC$, then a morphism $f: \cM \to \cN$ consists of a chain map $f:\cM(J,p;b) \to \cN(J,p;b)$ for each right marked interval $(J,p)$ with a boundary condition $b$, such that  for each interval $J'$ the diagram
-%\begin{equation*}
-%\xymatrix{
-%\cC(J';a,b) \tensor \cM(J,p;b) \ar[r]^{\text{gl}} \ar[d]^{\id \tensor f} & \cM(J' cup J,a) \ar[d]^f \\
-%\cC(J';a,b) \tensor \cN(J,p;b) \ar[r]^{\text{gl}}                                & \cN(J' cup J,a) 
-%}
-%\end{equation*}
-%commutes on the nose, and the diagram
-%\begin{equation*}
-%\xymatrix{
-%\CD{(J,p) \to (J',p')} \tensor \cM(J,p;a) \ar[r]^{\text{ev}} \ar[d]^{\id \tensor f} & \cM(J',p';a) \ar[d]^f \\
-%\CD{(J,p) \to (J',p')} \tensor \cN(J,p;a) \ar[r]^{\text{ev}}  & \cN(J',p';a) \\
-%}
-%\end{equation*}
-%commutes up to a weakly unique homotopy.
-%\end{defn}
-
-%The variations required for right modules and bimodules should be obvious.
-
-%\todo{duals}
-%\todo{ the functors $\hom_{\lmod{\cC}}\left(\cM \to -\right)$ and $\cM^* \tensor_{\cC} -$ from $\lmod{\cC}$ to $\Vect$ are naturally isomorphic}
-
--- a/text/appendixes/smallblobs.tex	Wed Jun 02 08:43:12 2010 -0700
+++ b/text/appendixes/smallblobs.tex	Wed Jun 02 11:45:19 2010 -0700
@@ -1,5 +1,5 @@
 %!TEX root = ../../blob1.tex
-\section{Small blobs}
+\section{The small blob complex}
 \label{appendix:small-blobs}
 
 Before proving Theorem \ref{thm:small-blobs}, we need a lemma allowing us to choose a convenient action of families of diffeomorphisms.
--- a/text/blobdef.tex	Wed Jun 02 08:43:12 2010 -0700
+++ b/text/blobdef.tex	Wed Jun 02 11:45:19 2010 -0700
@@ -25,23 +25,21 @@
 We of course define $\bc_0(X) = \lf(X)$.
 (If $X$ has nonempty boundary, instead define $\bc_0(X; c) = \lf(X; c)$.
 We'll omit this sort of detail in the rest of this section.)
-In other words, $\bc_0(X)$ is just the vector space of all (linearized) fields on $X$.
+In other words, $\bc_0(X)$ is just the vector space of fields on $X$.
 
-$\bc_1(X)$ is, roughly, the space of all local relations that can be imposed on $\bc_0(X)$.
-Less roughly (but still not the official definition), $\bc_1(X)$ is finite linear
-combinations of 1-blob diagrams, where a 1-blob diagram consists of
+We want the vector space $\bc_1(X)$ to capture `the space of all local relations that can be imposed on $\bc_0(X)$'.
+Thus we say  a $1$-blob diagram consists of
 \begin{itemize}
 \item An embedded closed ball (``blob") $B \sub X$.
-\item A field $r \in \cC(X \setmin B; c)$
-(for some $c \in \cC(\bd B) = \cC(\bd(X \setmin B))$).
-\item A local relation field $u \in U(B; c)$
-(same $c$ as previous bullet).
+\item A boundary condition $c \in \cC(\bdy B) = \cC(\bd(X \setmin B))$.
+\item A field $r \in \cC(X \setmin B; c)$.
+\item A local relation field $u \in U(B; c)$.
 \end{itemize}
 (See Figure \ref{blob1diagram}.)
 \begin{figure}[t]\begin{equation*}
 \mathfig{.6}{definition/single-blob}
 \end{equation*}\caption{A 1-blob diagram.}\label{blob1diagram}\end{figure}
-In order to get the linear structure correct, we (officially) define
+In order to get the linear structure correct, the actual definition is
 \[
 	\bc_1(X) \deq \bigoplus_B \bigoplus_c U(B; c) \otimes \lf(X \setmin B; c) .
 \]
@@ -61,26 +59,24 @@
 Note that the skein space $A(X)$
 is naturally isomorphic to $\bc_0(X)/\bd(\bc_1(X))) = H_0(\bc_*(X))$. This is Property \ref{property:skein-modules}, and also used in the second half of Property \ref{property:contractibility}.
 
-$\bc_2(X)$ is, roughly, the space of all relations (redundancies, syzygies) among the 
-local relations encoded in $\bc_1(X)$.
-More specifically, $\bc_2(X)$ is the space of all finite linear combinations of
-2-blob diagrams, of which there are two types, disjoint and nested.
-
+Next, we want the vector space $\bc_2(X)$ to capture `the space of all relations (redundancies, syzygies) among the 
+local relations encoded in $\bc_1(X)$'.
+More specifically, a $2$-blob diagram, comes in one of two types, disjoint and nested.
 A disjoint 2-blob diagram consists of
 \begin{itemize}
-\item A pair of closed balls (blobs) $B_0, B_1 \sub X$ with disjoint interiors.
-\item A field $r \in \cC(X \setmin (B_0 \cup B_1); c_0, c_1)$
+\item A pair of closed balls (blobs) $B_1, B_2 \sub X$ with disjoint interiors.
+\item A field $r \in \cC(X \setmin (B_1 \cup B_2); c_1, c_2)$
 (where $c_i \in \cC(\bd B_i)$).
-\item Local relation fields $u_i \in U(B_i; c_i)$, $i=1,2$. \nn{We're inconsistent with the indexes -- are they 0,1 or 1,2? I'd prefer 1,2.}
+\item Local relation fields $u_i \in U(B_i; c_i)$, $i=1,2$.
 \end{itemize}
 (See Figure \ref{blob2ddiagram}.)
 \begin{figure}[t]\begin{equation*}
 \mathfig{.6}{definition/disjoint-blobs}
 \end{equation*}\caption{A disjoint 2-blob diagram.}\label{blob2ddiagram}\end{figure}
-We also identify $(B_0, B_1, u_0, u_1, r)$ with $-(B_1, B_0, u_1, u_0, r)$;
+We also identify $(B_1, B_2, u_1, u_2, r)$ with $-(B_2, B_1, u_2, u_1, r)$;
 reversing the order of the blobs changes the sign.
-Define $\bd(B_0, B_1, u_0, u_1, r) = 
-(B_1, u_1, u_0\bullet r) - (B_0, u_0, u_1\bullet r) \in \bc_1(X)$.
+Define $\bd(B_1, B_2, u_1, u_2, r) = 
+(B_2, u_2, u_1\bullet r) - (B_1, u_1, u_2\bullet r) \in \bc_1(X)$.
 In other words, the boundary of a disjoint 2-blob diagram
 is the sum (with alternating signs)
 of the two ways of erasing one of the blobs.
@@ -88,48 +84,42 @@
 
 A nested 2-blob diagram consists of
 \begin{itemize}
-\item A pair of nested balls (blobs) $B_0 \sub B_1 \sub X$.
-\item A field $r \in \cC(X \setmin B_0; c_0)$
-(for some $c_0 \in \cC(\bd B_0)$), which is splittable along $\bd B_1$.
-\item A local relation field $u_0 \in U(B_0; c_0)$.
+\item A pair of nested balls (blobs) $B_1 \sub B_2 \sub X$.
+\item A field $r' \in \cC(B_2 \setminus B_1; c_1, c_2)$ (for some $c_1 \in \cC(\bdy B_1)$ and $c_2 \in \cC(\bdy B_2)$).
+\item A field $r \in \cC(X \setminus B_2; c_2)$.
+\item A local relation field $u \in U(B_1; c_1)$.
 \end{itemize}
 (See Figure \ref{blob2ndiagram}.)
 \begin{figure}[t]\begin{equation*}
 \mathfig{.6}{definition/nested-blobs}
 \end{equation*}\caption{A nested 2-blob diagram.}\label{blob2ndiagram}\end{figure}
-Let $r = r_1 \bullet r'$, where $r_1 \in \cC(B_1 \setmin B_0; c_0, c_1)$
-(for some $c_1 \in \cC(B_1)$) and
-$r' \in \cC(X \setmin B_1; c_1)$.
-Define $\bd(B_0, B_1, u_0, r) = (B_1, u_0\bullet r_1, r') - (B_0, u_0, r)$.
+Define $\bd(B_1, B_2, u, r', r) = (B_2, u\bullet r', r) - (B_1, u, r' \bullet r)$.
 Note that the requirement that
-local relations are an ideal with respect to gluing guarantees that $u_0\bullet r_1 \in U(B_1)$.
+local relations are an ideal with respect to gluing guarantees that $u\bullet r' \in U(B_2)$.
 As in the disjoint 2-blob case, the boundary of a nested 2-blob is the alternating
 sum of the two ways of erasing one of the blobs.
-If we erase the inner blob, the outer blob inherits the label $u_0\bullet r_1$.
+When  we erase the inner blob, the outer blob inherits the label $u\bullet r'$.
 It is again easy to check that $\bd^2 = 0$.
 
-As with the 1-blob diagrams, in order to get the linear structure correct it is better to define
-(officially)
+As with the $1$-blob diagrams, in order to get the linear structure correct the actual definition is 
 \begin{eqnarray*}
 	\bc_2(X) & \deq &
 	\left( 
-		\bigoplus_{B_0, B_1 \text{disjoint}} \bigoplus_{c_0, c_1}
-			U(B_0; c_0) \otimes U(B_1; c_1) \otimes \lf(X\setmin (B_0\cup B_1); c_0, c_1)
+		\bigoplus_{B_1, B_2 \text{disjoint}} \bigoplus_{c_1, c_2}
+			U(B_1; c_1) \otimes U(B_2; c_2) \otimes \lf(X\setmin (B_1\cup B_2); c_1, c_2)
 	\right) \\
 	&& \bigoplus \left( 
-		\bigoplus_{B_0 \subset B_1} \bigoplus_{c_0}
-			U(B_0; c_0) \otimes \lf(X\setmin B_0; c_0)
+		\bigoplus_{B_1 \subset B_2} \bigoplus_{c_1, c_2}
+			U(B_1; c_1) \otimes \lf(B_2 \setmin B_1; c_1) \tensor \cC(X \setminus B_2; c_2)
 	\right) .
 \end{eqnarray*}
-The final $\lf(X\setmin B_0; c_0)$ above really means fields splittable along $\bd B_1$,
-but we didn't feel like introducing a notation for that.
 For the disjoint blobs, reversing the ordering of $B_0$ and $B_1$ introduces a minus sign
-(rather than a new, linearly independent 2-blob diagram).
+(rather than a new, linearly independent 2-blob diagram). \nn{Hmm, I think we should be doing this for nested blobs too -- we shouldn't force the linear indexing of the blobs to have anything to do with the partial ordering by inclusion -- this is what happens below}
 
 Now for the general case.
 A $k$-blob diagram consists of
 \begin{itemize}
-\item A collection of blobs $B_i \sub X$, $i = 0, \ldots, k-1$.
+\item A collection of blobs $B_i \sub X$, $i = 1, \ldots, k$.
 For each $i$ and $j$, we require that either $B_i$ and $B_j$ have disjoint interiors or
 $B_i \sub B_j$ or $B_j \sub B_i$.
 (The case $B_i = B_j$ is allowed.
@@ -141,7 +131,7 @@
 \item Fields (boundary conditions) $c_i \in \cC(\bd B_i)$.
 (These are implied by the data in the next bullets, so we usually
 suppress them from the notation.)
-$c_i$ and $c_j$ must have identical restrictions to $\bd B_i \cap \bd B_j$
+The fields $c_i$ and $c_j$ must have identical restrictions to $\bd B_i \cap \bd B_j$
 if the latter space is not empty.
 \item A field $r \in \cC(X \setmin B^t; c^t)$,
 where $B^t$ is the union of all the twig blobs and $c^t \in \cC(\bd B^t)$
@@ -168,8 +158,7 @@
 		\left( \otimes_j U(B_j; c_j)\right) \otimes \lf(X \setmin B^t; c^t) .
 \]
 Here $\overline{B}$ runs over all configurations of blobs, satisfying the conditions above.
-$\overline{c}$ runs over all boundary conditions, again as described above.
-$j$ runs over all indices of twig blobs. The final $\lf(X \setmin B^t; c^t)$ must be interpreted as fields which are splittable along all of the blobs in $\overline{B}$.
+The index $\overline{c}$ runs over all boundary conditions, again as described above and $j$ runs over all indices of twig blobs. The final $\lf(X \setmin B^t; c^t)$ must be interpreted as fields which are splittable along all of the blobs in $\overline{B}$.
 
 The boundary map 
 \[
@@ -186,9 +175,9 @@
 where $r_l$ is the restriction of $r$ to $B_l \setmin B_j$.
 Finally, define
 \eq{
-    \bd(b) = \sum_{j=0}^{k-1} (-1)^j E_j(b).
+    \bd(b) = \sum_{j=1}^{k} (-1)^{j+1} E_j(b).
 }
-The $(-1)^j$ factors imply that the terms of $\bd^2(b)$ all cancel.
+The $(-1)^{j+1}$ factors imply that the terms of $\bd^2(b)$ all cancel.
 Thus we have a chain complex.
 
 We define the {\it support} of a blob diagram $b$, $\supp(b) \sub X$, 
@@ -205,7 +194,7 @@
 \begin{itemize}
 \item $p(\emptyset) = pt$, where $\emptyset$ denotes a 0-blob diagram or empty tree;
 \item $p(a \du b) = p(a) \times p(b)$, where $a \du b$ denotes the distant (non-overlapping) union of two blob diagrams (equivalently, join two trees at the roots); and
-\item $p(\bar{b}) = \kone(p(b))$, where $\bar{b}$ is obtained from $b$ by adding an outer blob which encloses all the others.
+\item $p(\bar{b}) = \kone(p(b))$, where $\bar{b}$ is obtained from $b$ by adding an outer blob which encloses all the others (equivalently, add a new edge to the root, with the new vertex becoming the root).
 \end{itemize}
 For example, a diagram of $k$ strictly nested blobs corresponds to a $k$-simplex, while
 a diagram of $k$ disjoint blobs corresponds to a $k$-cube.
--- a/text/hochschild.tex	Wed Jun 02 08:43:12 2010 -0700
+++ b/text/hochschild.tex	Wed Jun 02 11:45:19 2010 -0700
@@ -7,8 +7,7 @@
 greater than zero.
 In this section we analyze the blob complex in dimension $n=1$.
 We find that $\bc_*(S^1, \cC)$ is homotopy equivalent to the 
-Hochschild complex of the 1-category $\cC$.
-\nn{cat vs fields --- need to make sure this is clear}
+Hochschild complex of the 1-category $\cC$. (Recall from \S \ref{sec:example:traditional-n-categories(fields)} that a $1$-category gives rise to a $1$-dimensional system of fields; as usual, talking about the blob complex with coefficients in a $n$-category means first passing to the corresponding $n$ dimensional system of fields.)
 Thus the blob complex is a natural generalization of something already
 known to be interesting in higher homological degrees.