gapt.proofs.nd.Utils.scala Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of gapt_3 Show documentation

General Architecture for Proof Theory

The newest version!

package gapt.proofs.nd

import gapt.expr.Var
import gapt.expr.util.freeVariables

object freeVariablesND {
  def apply(p: NDProof): Set[Var] = p match {
    case ExistsElimRule(leftSubProof, rightSubProof, _, eigenVariable) =>
      freeVariables(p.conclusion) ++ apply(leftSubProof) ++ apply(rightSubProof) - eigenVariable
    case ForallIntroRule(subProof, eigenVariable, _) =>
      apply(subProof) - eigenVariable
    case InductionRule(cases, main, term) =>
      freeVariables(p.conclusion) ++ (cases flatMap { c =>
        apply(c.proof) -- c.eigenVars
      })
    case _ =>
      freeVariables(p.conclusion) ++ p.immediateSubProofs.flatMap(apply)
  }
}