  Given a linearly ordered set I, every surjective map p: A --> I endows the
set A with a structure of set of preferences by "replacing" the elements of I
with their inverse images via p considered as "balloons" (sets endowed with an
equivalence relation), lifting the linear order on A, and "agglutinating" this
structure with the balloons. Every ballooning A of a structure of linearly
ordered set I is a set of preferences whose preference relation (not
necessarily complete) is negatively transitive and every such structure on a
given set A can be obtained by ballooning of certain structure of a linearly
ordered set I, intrinsically encoded in A. In other words, the difference
between linearity and negative transitivity is constituted of balloons. As a
consequence of this characterization, under certain natural topological
conditions on the set of preferences A furnished with its interval topology,
the existence of a continuous generalized utility function on A is proved.
