The first challenge problem that I had in mind is how to represent one or more marriages in one’s favorite modeling language or logic. The concept of interest for the first challenge is what someone called marriage as a situation which has a husband and wife which are in a spousal relationship. I would expect to look at some of the other aspects later. Maybe I missed something, but I have yet to see anyone actually try to give FOL axioms.
The kind of modeling/logic representation that I am looking for would have other models in the sense of logic which are not related to marriage. For the challenge purpose one could replace Marriage with your favorite diatomic molecules. Here a diatomic molecule is a molecule composed only of two atoms which are bonded together. The bonding relationship is analogous to the spousal relationship.
The reason that I at least am interested in this example is that sorting out how it is best done goes a long way to deal with what Cory calls composite structures – which are common in many domains.
There are lots of further challenges planned.
I you have anything to offer in the way of a model or axioms please send it to the model challenge mailing list.