Home | Unification Algorithm | Fist order of unification | Examples in Unification
When a variable is given a value through unification, that variable is then said to become instantiated or bound to that value.
A variable that is bound to a value is said to be ground. A variable that has not been unified to any value is said to be unbound.
The process of instantiating a variable to a value is also called substitution. In fact, it is accurate to think of instantiation as the literal replacement (or substitution) of that variable by the value.
The set of all substitutions made during the unification of two terms is called a substitution set.
An atom is a basic proposition and is unified similarly to a Prolog term.