In this category, the entry of mathematical formulas or musical scores is
considered. In both these types of graphical behavior there is an aspect of
symbolical and structural information. This means that apart from a symbol
identity like ``Greek alpha'', its geometrical relation to the other
graphical objects plays an essential role. Interestingly, the entering of
formulas is sometimes used as an example of the ease of * Direct
Manipulation*. It has become clear however, that the correct entry of
formulas with the pen is a tedious process, if rules for graphical style
are not applied within the interface algorithm. As a worst case example,
the user must enter four similar formulas with a tantalizing accurate
positioning of subscripts and superscripts etc. four times, with the risk
of very annoying spacing differences between these formulas. A combination
of rule-based approaches, as in LaTeX, and the actual use of interactive
pen input is the best solution to this problem. Finally, both in the
automatic recognition of mathematical formulas and musical scores, context
information is needed and is in practice actually used to solve shape
classification ambiguities.

Thu May 18 16:00:17 MET DST 1995