Thrown if Extended Herbrand Sequent is unprovable.
Thrown if Extended Herbrand Sequent is unprovable. In theory this does not happen. In practice it does happen if the method used for searching a proof covers a too weak theory (e.g. no equality) or is not complete.
Represents a schematic extended Herbrand sequent.
Represents a schematic extended Herbrand sequent.
Formulas of the original end-sequent, together with their instances.
Instances of the cut-implications.