public bool Equals(ObjectVariableTerm other)
 {
     if (other is null)
     {
         return(false);
     }
     if (ReferenceEquals(this, other))
     {
         return(true);
     }
     return(ObjectVariable.Equals(other.ObjectVariable));
 }
 public bool Equals(QuantifierFormula other)
 {
     if (other is null)
     {
         return(false);
     }
     if (ReferenceEquals(this, other))
     {
         return(true);
     }
     return(Quantifier.Equals(other.Quantifier) &&
            ObjectVariable.Equals(other.ObjectVariable) &&
            SubFormula.Equals(other.SubFormula));
 }