Lecture 31: Residuating Equational Constraints

After finishing the proof of cut elimination which heavily relies on the completeness of regular derivations, we residuate equational constraints. This is similar to the same process for the logic without equality, except that now implicational formulas may arises in the residuated constraints. The corresponding problem is called simultaneous rigid E-unification.

Reading

• Pages 115-116 of Handout 16 on Equality (also availabe in PDF format).

Key Concepts

• Admissibility of cut
• Rigid equational constraints
• Simultaneous rigid E-unification

Links

• Previous lecture: Cut Elimination with Equality
• Next lecture: Ordering