Unification Unification PC Method Form the set of all instances of premises and form the conjunction of all instances of the conclusion. Convert each atomic formula to a propositional constant.
Relational logic is equivalent to propositional calculus.
The relational resolution principle is a rule of inference for relational calculus analogous to the propositional resolution principle for propositional calculus. The search space using the resolution principle is much smaller than for deduction using the standard axiom schemata. Substitution A substitution is a finite mapping of variables to terms. The variables together constitute the domain of the substitution, and the replacement terms constitite the range . X A substitution is pure if and only if all replacements are free of the variables in the domain of the substitution.