AIMA.Core.Logic.FOL.RemoveQuantifiers.visitQuantifiedSentence C# (CSharp) Метод

        public Object visitQuantifiedSentence(QuantifiedSentence sentence,
                Object arg)
        {
            Sentence quantified = sentence.getQuantified();
            List<Variable> universalScope = (List<Variable>)arg;

            // Skolemize: Skolemization is the process of removing existential
            // quantifiers by elimination. This is done by introducing Skolem
            // functions. The general rule is that the arguments of the Skolem
            // function are all the universally quantified variables in whose
            // scope the existential quantifier appears.
            if (Quantifiers.isEXISTS(sentence.getQuantifier()))
            {
                Dictionary<Variable, Term> skolemSubst = new Dictionary<Variable, Term>();
                foreach (Variable eVar in sentence.getVariables())
                {
                    if (universalScope.Count > 0)
                    {
                        // Replace with a Skolem Function
                        String skolemFunctionName = parser.getFOLDomain()
                                .addSkolemFunction();
                        skolemSubst.Add(eVar, new Function(skolemFunctionName,
                                new List<Term>(universalScope)));
                    }
                    else
                    {
                        // Replace with a Skolem Constant
                        String skolemConstantName = parser.getFOLDomain()
                                .addSkolemConstant();
                        skolemSubst.Add(eVar, new Constant(skolemConstantName));
                    }
                }

                Sentence skolemized = substVisitor.subst(skolemSubst, quantified);
                return skolemized.accept(this, arg);
            }

            // Drop universal quantifiers.
            if (Quantifiers.isFORALL(sentence.getQuantifier()))
            {
                // Add to the universal scope so that
                // existential skolemization may be done correctly
                universalScope.AddRange(sentence.getVariables());

                Sentence droppedUniversal = (Sentence)quantified.accept(this, arg);

                // Enusre my scope is removed before moving back up
                // the call stack when returning
                foreach (Variable s in sentence.getVariables())
                {
                    universalScope.Remove(s);
                }
               
                return droppedUniversal;
            }

            // Should not reach here as have already
            // handled the two quantifiers.
            throw new ApplicationException("Unhandled Quantifier:"
                    + sentence.getQuantifier());
        }
    }