abstract class Term

case class Var(s: String) extends Term

case class Consts(s: String) extends Term

case class Fun(s: String, ts: List[Term]) extends Term

abstract class Form

case object True extends Form

case object False extends Form

case class And(f1: Form, f2: Form) extends Form

case class Or(f1: Form, f2: Form) extends Form

case class Imp(f1: Form, f2: Form) extends Form

case class Neg(f: Form) extends Form

case class Pred(s: String, ts: List[Term]) extends Form

case class Judgement(Gamma: List[Form], F: Form) {

  def lhs = Gamma

  def rhs = F

}