Kdy: October 14, 2026
Kde:
In one or another logic, and assuming the presence of the symbols ⊥ and ⊤ for falsity and truth, interpolation theorem IT is the following claim. If the formula φ→ψ is valid, as determined by the semantics of the logic in question, then there exists a formula μ, called interpolant of φ and ψ, such that φ→μ and μ→ψ are valid and μ is built up from the extralogical symbols that occur in both φ and ψ. In propositional logic extralogical symbols are just atoms, and examples of logics for which …