A trajectory is a *sequence* of states.

deal.tex

@@ -545,7 +545,7 @@ $\Phi_s : T \to X$, $\Phi_s(t) = \Phi(s, t)$, determining the
 \emph{trajectory} of $\Phi$ through $s$.
 $\Ima \Phi_s = \{\Phi(s, t) \mid t\in T\}$.  If $T = \mathbb{Z}$ or
 $T = \mathbb{R}$, then the trajectory $\Ima \Phi_s$ can be interpreted
-as the set of all states through which $\Phi$ goes before and after
+as the sequence of all states through which $\Phi$ goes before and after
 reaching $s$.  If $T = \mathbb{N}$, then the trajectory through $s$ is
 the iteration of $F$: $\{F^k(s) \mid k \in \mathbb{N}\}$, where
 $F^0(s) = s$, $F^1(s) = F(s)$, $F^2(s) = F(F(s))$, etc.