15-815 Automated Theorem Proving
Lecture 10: Unification
The principal new difficulty in proof search in the presence
of quantifiers is how to pick terms for their instantiation.
The usual solution is to postpone that choice and use
free variables. Constraints that search places on the free
variables are then solved by a process called unification.
We show how unification is related to proof search, and give an
algorithm for solving unification problems. Even though unification is
motivated by backward search, it is also important for forward search in
the style of the inverse method or resolution.