Notice that we do not need all of the information contained in configurations, just those labellings that can be changed by future catenations.
Another direction for further study is the behaviour of infinite catenations, like the usual infinite word asymptotics (cf.
2005) and admits a natural definition of catenation.
Catenation of x and y with respect to a merging function m : [SIGMA] [SIGMA] [SIGMA] [right arrow] [SIGMA] is defined as
m] catenation from figures in X [subset or equal to] [[SIGMA].