text/ncat.tex
changeset 801 33b3e0c065d2
parent 800 d0b9238aad5d
child 802 e3ddb8605e32
equal deleted inserted replaced
800:d0b9238aad5d 801:33b3e0c065d2
   667 Before stating the axiom we need a few preliminary definitions.
   667 Before stating the axiom we need a few preliminary definitions.
   668 If $P$ is a poset let $P\times I$ denote the product poset, where $I = \{0, 1\}$ with ordering $0\le 1$.
   668 If $P$ is a poset let $P\times I$ denote the product poset, where $I = \{0, 1\}$ with ordering $0\le 1$.
   669 Let $\Cone(P)$ denote $P$ adjoined an additional object $v$ (the vertex of the cone) with $p\le v$ for all objects $p$ of $P$.
   669 Let $\Cone(P)$ denote $P$ adjoined an additional object $v$ (the vertex of the cone) with $p\le v$ for all objects $p$ of $P$.
   670 Finally, let $\vcone(P)$ denote $P\times I \cup \Cone(P)$, where we identify $P\times \{0\}$ with the base of the cone.
   670 Finally, let $\vcone(P)$ denote $P\times I \cup \Cone(P)$, where we identify $P\times \{0\}$ with the base of the cone.
   671 We call $P\times \{1\}$ the base of $\vcone(P)$.
   671 We call $P\times \{1\}$ the base of $\vcone(P)$.
   672 (See Figure \nn{need figure}.)
   672 (See Figure \ref{vcone-fig}.)
       
   673 \begin{figure}[t]
       
   674 $$\mathfig{.65}{tempkw/vcone}$$
       
   675 \caption{(a) $P$, (b) $P\times I$, (c) $\Cone(P)$, (d) $\vcone(P)$}\label{vcone-fig}
       
   676 \end{figure}
   673 
   677 
   674 \nn{maybe call this ``splittings" instead of ``V-cones"?}
   678 \nn{maybe call this ``splittings" instead of ``V-cones"?}
   675 
   679 
   676 \begin{axiom}[V-cones]
   680 \begin{axiom}[V-cones]
   677 \label{axiom:vcones}
   681 \label{axiom:vcones}