Different situations may require the presentation of
different types of examples. For instance, some sit-
uations require the presentation of positive examples
only, while others require both positive and nega-
tive examples. Furthermore, different examples often
have specific presentation requirements: they need
to appear in an appropriate sequence, be introduced
properly and often require associated prompts. It
is important to be able to identify what is needed
in which case, and what needs to be done in pre-
senting the example. A categorization of examples,
along with their associated presentation requirements
would help tremendously. This issue is particularly
salient in the design of a computational framework for
the generation of tutorial descriptions which include
examples. Previous work on characterizing exam-
ples has approached the issue from the direction of
when different types of examples should be provided,
rather than what characterizes the different types. In
this paper, w e extend previous work on example char-
acterization in two ways: (i) we show that the scope
of the characterization must be extended to include
not just the example, but also the surrounding con-
text, and (ii) w e characterize examples in terms of
three orthogonal dimensions: the information con-
lent, the intended audience, and the knowledge type.
We present descriptions from text-books on USP to
illustrate our points, and describe h o w such catego-
rizations can be effectively used by a computational
system to generate descriptions that incorporate ex-
amples.
