An infon is sometimes written:

where **p** is one of **-,+**. The expressions:

are intended to convey the information that are (are
not, respectively) related by **q**. We might think of **+** as the basic
polarity, then **-** expresses the notion of complement.

It is not clear to me whether or not situation theory requires **q** to
have an explicit arity.

We could implement infons as pairings of terms.
Alternatively, we could have a primitive class of infons and their
complements, or primitive *relational expressions* from which we
can form positive and negative infons. The last two options allow us
to ignore the question of the arity of an infon for the moment.

A term **r** is a *relational expression* iff:

If **r** is a relational expression, then **+r,-r** are infons:

The terms **+r,-r** are intended to be used in place of expressions of
the form

We can form the conjunction and disjunction of infons. For the moment we will add the operators . Depending upon how we model Austinian Propositions, it may be possible to make these definitional. However implemented, they must satisfy the closure conditions

A situation-theoretic relation can be encoded as -abstracts of infons. Then we can have:

Note that expressions of are also called
situation-theoretic *properties*.

Chris Fox