So how do we go about describing such diagrams? Here is a first version. But there are problems connected with describing these diagrams. Variations are possible. e.g. for the source figure (A) we could have either ``a rectangle with a triangle on top'' or ``a rectangle with a triangle on its perimeter". For the target figure (B) we could have ``a rectangle with a triangle inside it'' or ``a triangle with a rectangle outside it''. These alternatives represent some of different relationships that can hold between objects.
So we need to do three things: adopt a syntactic convention; adopt a semantic convention; and drop synonyms and alternatives. Here's the syntactic convention we adopt: =6cm /home/dream4/paul/teaching/ai1problemsolving/slides/evansanalogy/slide7.eps
The semantic convention is one of consistency. For example, on(triangle, rectangle) means ``the triangle is on top of the rectangle''.
For example a triangle entirely inside a rectangle might be described by any of:
We have to choose exactly one of these - say, inside(triangle, rectangle). Note that inside is the predicate and triangle and rectangle are the arguments.
=6cm
/home/dream4/paul/teaching/ai1problemsolving/slides/evansanalogy/slide3.eps
In this example of a symbolic representation:
Note that the Rule is: ``change on to in''
We now show how to refine the description further. Objects get a unique name.
=6cm
/home/dream4/paul/teaching/ai1problemsolving/slides/evansanalogy/slidedescdeb.eps
We also need to define the similarities that exist between the two diagrams. =6cm /home/dream4/paul/teaching/ai1problemsolving/slides/evansanalogy/slidesim.eps
NB there are more similarities possible!