In this paper we consider the ARTMAP architecture for situations requi
ring learning of many-to-one maps. It is shown that if ARTMAP is repea
tedly presented with a list of input/output pairs, it establishes the
required mapping in at most M(a) - 1 list presentations, where M(a) co
rresponds to the total number of ones in each one of the input pattern
s. Other useful properties, associated with the learning of the mappin
g represented by an arbitrary list of input/output pairs, are also exa
mined, These properties reveal some of the characteristics of learning
in ARTMAP when it is used as a tool in establishing an arbitrary mapp
ing from a binary input space to a binary output space. The results pr
esented in this paper are valid for the fast learning case, and for sm
all beta(a) values, where beta(a) is a parameter associated with the a
daptation of bottom-up weights in one of the ART1 modules of ARTMAP.