# HG changeset patch # User Scott Morrison # Date 1294701953 28800 # Node ID 0cbef0258d724f0fd05ad3aab6dbaca7faca8bc2 # Parent b8f7de7a42066714bec39b808a024f1bebee2759 minor changes to kevin's new paragraphs diff -r b8f7de7a4206 -r 0cbef0258d72 text/intro.tex --- a/text/intro.tex Mon Jan 10 14:18:52 2011 -0800 +++ b/text/intro.tex Mon Jan 10 15:25:53 2011 -0800 @@ -509,8 +509,8 @@ that we are enriching in. We have decided to call them ``$A_\infty$ $n$-categories", since they are a natural generalization of the familiar $A_\infty$ 1-categories. -Other possible names include ``homotopy $n$-categories" and ``infinity $n$-categories". -When we need to emphasize that we are talking about an $n$-category which is not $A_\infty$ +We also considered the names ``homotopy $n$-categories" and ``infinity $n$-categories". +When we need to emphasize that we are talking about an $n$-category which is not $A_\infty$ in this sense we will say ``ordinary $n$-category". % small problem: our n-cats are of course strictly associative, since we have more morphisms. % when we say ``associative only up to homotopy" above we are thinking about @@ -520,8 +520,8 @@ more traditional and combinatorial definitions. We will call instances of our definition ``disk-like $n$-categories", since $n$-dimensional disks play a prominent role in the definition. -(In general we prefer to ``$k$-ball" to ``$k$-disk", but ``ball-like" doesn't roll off -the tongue as well as "disk-like".) +(In general we prefer ``$k$-ball" to ``$k$-disk", but ``ball-like" doesn't roll off +the tongue as well as ``disk-like''.) Another thing we need a name for is the ability to rotate morphisms around in various ways. For 2-categories, ``pivotal" is a standard term for what we mean. @@ -530,9 +530,9 @@ rotating $k$-morphisms correspond to all the ways of rotating $k$-balls. We sometimes refer to this as ``strong duality", and sometimes we consider it to be implied by ``disk-like". -(But beware: disks can come in various flavors, and some of them (such as framed disks) +(But beware: disks can come in various flavors, and some of them, such as framed disks, don't actually imply much duality.) -Another possibility here is ``pivotal $n$-category". +Another possibility considered here was ``pivotal $n$-category", but we prefer to preserve pivotal for its usual sense. It will thus be a theorem that our disk-like 2-categories are equivalent to pivotal 2-categories, c.f. \S \ref{ssec:2-cats}. Finally, we need a general name for isomorphisms between balls, where the balls could be piecewise linear or smooth or topological or Spin or framed or etc., or some combination thereof. diff -r b8f7de7a4206 -r 0cbef0258d72 text/ncat.tex --- a/text/ncat.tex Mon Jan 10 14:18:52 2011 -0800 +++ b/text/ncat.tex Mon Jan 10 15:25:53 2011 -0800 @@ -678,12 +678,12 @@ An $n$-category consists of the following data: \begin{itemize} -\item Functors $\cC_k$ from $k$-balls to sets, $0\le k\le n$ (Axiom \ref{axiom:morphisms}) -\item Boundary natural transformations $\cC_k \to \cl{\cC}_{k-1} \circ \bd$ (Axiom \ref{nca-boundary}) -\item Composition/gluing maps $\gl_Y : \cC(B_1)_E \times_{\cC(Y)} \cC(B_2)_E \to \cC(B_1\cup_Y B_2)_E$ (Axiom \ref{axiom:composition}) -\item Product/identity maps $\pi^*:\cC(X)\to \cC(E)$ for each pinched product $\pi:E\to X$ (Axiom \ref{axiom:product}) -\item If enriching in an auxiliary category, additional structure on $\cC_n(X; c)$ -\item In the $A_\infty$ case, an action of $C_*(\Homeo_\bd(X))$, and similarly for families of collar maps (Axiom \ref{axiom:families}) +\item Functors $\cC_k$ from $k$-balls to sets, $0\le k\le n$ (Axiom \ref{axiom:morphisms}). +\item Boundary natural transformations $\cC_k \to \cl{\cC}_{k-1} \circ \bd$ (Axiom \ref{nca-boundary}). +\item Composition/gluing maps $\gl_Y : \cC(B_1)_E \times_{\cC(Y)} \cC(B_2)_E \to \cC(B_1\cup_Y B_2)_E$ (Axiom \ref{axiom:composition}). +\item Product/identity maps $\pi^*:\cC(X)\to \cC(E)$ for each pinched product $\pi:E\to X$ (Axiom \ref{axiom:product}). +\item If enriching in an auxiliary category, additional structure on $\cC_n(X; c)$. +\item In the $A_\infty$ case, an action of $C_*(\Homeo_\bd(X))$, and similarly for families of collar maps (Axiom \ref{axiom:families}). \end{itemize} The above data must satisfy the following conditions: \begin{itemize}