# HG changeset patch # User Kevin Walker # Date 1306554862 21600 # Node ID 6a1b6c2de20159b19311ddb862fbbaa05cad2312 # Parent c0cdde54913a531626f7bee08e5e43315aea2f89 more reorganization of n-cat defs diff -r c0cdde54913a -r 6a1b6c2de201 blob_changes_v3 --- a/blob_changes_v3 Fri May 27 13:43:20 2011 -0600 +++ b/blob_changes_v3 Fri May 27 21:54:22 2011 -0600 @@ -21,6 +21,8 @@ - clarified that the "cell complexes" in string diagrams are actually a bit more general - added remark to insure that the poset of decompositions is a small category - corrected statement of module to category restrictions +- reduced intermingling for the various n-cat definitions (plain, enriched, A-infinity) +- diff -r c0cdde54913a -r 6a1b6c2de201 text/ncat.tex --- a/text/ncat.tex Fri May 27 13:43:20 2011 -0600 +++ b/text/ncat.tex Fri May 27 21:54:22 2011 -0600 @@ -558,16 +558,27 @@ \medskip -All of the axioms listed above hold for both ordinary $n$-categories and $A_\infty$ $n$-categories. -The last axiom (below), concerning actions of -homeomorphisms in the top dimension $n$, distinguishes the two cases. + + -We start with the ordinary $n$-category case. +%All of the axioms listed above hold for both ordinary $n$-categories and $A_\infty$ $n$-categories. +%The last axiom (below), concerning actions of +%homeomorphisms in the top dimension $n$, distinguishes the two cases. + +%We start with the ordinary $n$-category case. + +The next axiom says, roughly, that we have strict associativity in dimension $n$, +even we we reparameterize our $n$-balls. \begin{axiom}[\textup{\textbf{[preliminary]}} Isotopy invariance in dimension $n$] -Let $X$ be an $n$-ball and $f: X\to X$ be a homeomorphism which restricts -to the identity on $\bd X$ and is isotopic (rel boundary) to the identity. -Then $f$ acts trivially on $\cC(X)$; that is $f(a) = a$ for all $a\in \cC(X)$. +Let $X$ be an $n$-ball, $b \in \cC(X)$, and $f: X\to X$ be a homeomorphism which +acts trivially on the restriction $\bd b$ of $b$ to $\bd X$. +(Keep in mind the important special case where $f$ restricted to $\bd X$ is the identity.) +Suppose furthermore that $f$ is isotopic to the identity through homeomorphisms which +trivially on $\bd b$. +Then $f(b) = b$. +In particular, homeomorphisms which are isotopic to the identity rel boundary act trivially on +all of $\cC(X)$. \end{axiom} This axiom needs to be strengthened to force product morphisms to act as the identity. @@ -640,19 +651,18 @@ %\addtocounter{axiom}{-1} \begin{axiom}[\textup{\textbf{[ordinary version]}} Extended isotopy invariance in dimension $n$.] \label{axiom:extended-isotopies} -Let $X$ be an $n$-ball and $f: X\to X$ be a homeomorphism which restricts -to the identity on $\bd X$ and isotopic (rel boundary) to the identity. -Then $f$ acts trivially on $\cC(X)$. +Let $X$ be an $n$-ball, $b \in \cC(X)$, and $f: X\to X$ be a homeomorphism which +acts trivially on the restriction $\bd b$ of $b$ to $\bd X$. +Suppose furthermore that $f$ is isotopic to the identity through homeomorphisms which +trivially on $\bd b$. +Then $f(b) = b$. In addition, collar maps act trivially on $\cC(X)$. \end{axiom} -\smallskip +\medskip -For $A_\infty$ $n$-categories, we replace -isotopy invariance with the requirement that families of homeomorphisms act. -For the moment, assume that our $n$-morphisms are enriched over chain complexes. -Let $\Homeo_\bd(X)$ denote homeomorphisms of $X$ which fix $\bd X$ and -$C_*(\Homeo_\bd(X))$ denote the singular chains on this space. + + \nn{begin temp relocation} @@ -673,6 +683,17 @@ \nn{end temp relocation} + +\smallskip + +For $A_\infty$ $n$-categories, we replace +isotopy invariance with the requirement that families of homeomorphisms act. +For the moment, assume that our $n$-morphisms are enriched over chain complexes. +Let $\Homeo_\bd(X)$ denote homeomorphisms of $X$ which fix $\bd X$ and +$C_*(\Homeo_\bd(X))$ denote the singular chains on this space. + + + %\addtocounter{axiom}{-1} \begin{axiom}[\textup{\textbf{[$A_\infty$ version]}} Families of homeomorphisms act in dimension $n$.] \label{axiom:families}