contains the operators of {@link de.uka.ilkd.key.logic.Term}s. Operators may be {@link de.uka.ilkd.key.logic.op.Quantifier}s or {@link de.uka.ilkd.key.logic.op.SubstOp}s that bind variables for subterms, but also {@link de.uka.ilkd.key.logic.op.Modality}s, or {@link de.uka.ilkd.key.logic.op.QuanUpdateOperator}s. Many of the operators are constantly defined in {@link de.uka.ilkd.key.logic.op.Op}s. An operator can be a {@link de.uka.ilkd.key.logic.op.TermSymbol}s, such as a {@link de.uka.ilkd.key.logic.op.Function} or a variable. There are several kind of variables: {@link de.uka.ilkd.key.logic.op.LogicVariable}s (variables that must be bound but do not occur in programs), {@link de.uka.ilkd.key.logic.op.ProgramVariable}s (allowed both in programs and in logic, but not boundable), {@link de.uka.ilkd.key.logic.op.Metavariable}s, and {@link de.uka.ilkd.key.logic.op.SchemaVariable}s for {@link de.uka.ilkd.key.rule.Taclet}s. Last modified: Mon Apr 18 09:42:36 MEST 2005