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-rw-r--r--src/theory/quantifiers/proof_checker.cpp1
-rw-r--r--src/theory/quantifiers/skolemize.cpp84
-rw-r--r--src/theory/quantifiers/skolemize.h20
-rw-r--r--src/theory/quantifiers_engine.cpp11
4 files changed, 83 insertions, 33 deletions
diff --git a/src/theory/quantifiers/proof_checker.cpp b/src/theory/quantifiers/proof_checker.cpp
index 8371492b5..5f6e4a119 100644
--- a/src/theory/quantifiers/proof_checker.cpp
+++ b/src/theory/quantifiers/proof_checker.cpp
@@ -97,6 +97,7 @@ Node QuantifiersProofRuleChecker::checkInternal(
else
{
std::vector<Node> echildren(children[0][0].begin(), children[0][0].end());
+ echildren[1] = echildren[1].notNode();
exists = nm->mkNode(EXISTS, echildren);
}
std::vector<Node> skolems;
diff --git a/src/theory/quantifiers/skolemize.cpp b/src/theory/quantifiers/skolemize.cpp
index 43f656a2a..61dd0c15e 100644
--- a/src/theory/quantifiers/skolemize.cpp
+++ b/src/theory/quantifiers/skolemize.cpp
@@ -14,6 +14,7 @@
#include "theory/quantifiers/skolemize.h"
+#include "expr/skolem_manager.h"
#include "options/quantifiers_options.h"
#include "theory/quantifiers/quantifiers_attributes.h"
#include "theory/quantifiers/term_util.h"
@@ -27,24 +28,65 @@ namespace CVC4 {
namespace theory {
namespace quantifiers {
-Skolemize::Skolemize(QuantifiersEngine* qe, context::UserContext* u)
- : d_quantEngine(qe), d_skolemized(u)
+Skolemize::Skolemize(QuantifiersEngine* qe,
+ context::UserContext* u,
+ ProofNodeManager* pnm)
+ : d_quantEngine(qe),
+ d_skolemized(u),
+ d_pnm(pnm),
+ d_epg(pnm == nullptr ? nullptr
+ : new EagerProofGenerator(pnm, u, "Skolemize::epg"))
{
}
-Node Skolemize::process(Node q)
+TrustNode Skolemize::process(Node q)
{
+ Assert(q.getKind() == FORALL);
// do skolemization
- if (d_skolemized.find(q) == d_skolemized.end())
+ if (d_skolemized.find(q) != d_skolemized.end())
{
+ return TrustNode::null();
+ }
+ Node lem;
+ ProofGenerator* pg = nullptr;
+ if (isProofEnabled() && !options::dtStcInduction()
+ && !options::intWfInduction())
+ {
+ // if using proofs and not using induction, we use the justified
+ // skolemization
+ NodeManager* nm = NodeManager::currentNM();
+ SkolemManager* skm = nm->getSkolemManager();
+ std::vector<Node> echildren(q.begin(), q.end());
+ echildren[1] = echildren[1].notNode();
+ Node existsq = nm->mkNode(EXISTS, echildren);
+ Node res = skm->mkSkolemize(existsq, d_skolem_constants[q], "skv");
+ Node qnot = q.notNode();
+ CDProof cdp(d_pnm);
+ cdp.addStep(res, PfRule::SKOLEMIZE, {qnot}, {});
+ std::shared_ptr<ProofNode> pf = cdp.getProofFor(res);
+ std::vector<Node> assumps;
+ assumps.push_back(qnot);
+ std::shared_ptr<ProofNode> pfs = d_pnm->mkScope({pf}, assumps);
+ lem = nm->mkNode(IMPLIES, qnot, res);
+ d_epg->setProofFor(lem, pfs);
+ pg = d_epg.get();
+ Trace("quantifiers-sk")
+ << "Skolemize (with proofs) : " << d_skolem_constants[q] << " for "
+ << std::endl;
+ Trace("quantifiers-sk") << " " << q << std::endl;
+ Trace("quantifiers-sk") << " " << res << std::endl;
+ }
+ else
+ {
+ // otherwise, we use the more general skolemization with inductive
+ // strengthening, which does not support proofs
Node body = getSkolemizedBody(q);
NodeBuilder<> nb(kind::OR);
nb << q << body.notNode();
- Node lem = nb;
- d_skolemized[q] = lem;
- return lem;
+ lem = nb;
}
- return Node::null();
+ d_skolemized[q] = lem;
+ return TrustNode::mkTrustLemma(lem, pg);
}
bool Skolemize::getSkolemConstants(Node q, std::vector<Node>& skolems)
@@ -274,16 +316,8 @@ Node Skolemize::mkSkolemizedBody(Node f,
ret, f.getAttribute(InstLevelAttribute()));
}
- if (Trace.isOn("quantifiers-sk"))
- {
- Trace("quantifiers-sk") << "Skolemize : ";
- for (unsigned i = 0; i < sk.size(); i++)
- {
- Trace("quantifiers-sk") << sk[i] << " ";
- }
- Trace("quantifiers-sk") << "for " << std::endl;
- Trace("quantifiers-sk") << " " << f << std::endl;
- }
+ Trace("quantifiers-sk") << "Skolemize : " << sk << " for " << std::endl;
+ Trace("quantifiers-sk") << " " << f << std::endl;
return ret;
}
@@ -291,14 +325,17 @@ Node Skolemize::mkSkolemizedBody(Node f,
Node Skolemize::getSkolemizedBody(Node f)
{
Assert(f.getKind() == FORALL);
- if (d_skolem_body.find(f) == d_skolem_body.end())
+ std::unordered_map<Node, Node, NodeHashFunction>::iterator it =
+ d_skolem_body.find(f);
+ if (it == d_skolem_body.end())
{
std::vector<TypeNode> fvTypes;
std::vector<TNode> fvs;
Node sub;
std::vector<unsigned> sub_vars;
- d_skolem_body[f] = mkSkolemizedBody(
+ Node ret = mkSkolemizedBody(
f, f[1], fvTypes, fvs, d_skolem_constants[f], sub, sub_vars);
+ d_skolem_body[f] = ret;
// store sub quantifier information
if (!sub.isNull())
{
@@ -320,8 +357,9 @@ Node Skolemize::getSkolemizedBody(Node f)
f, f[0][i], d_skolem_constants[f][i]);
}
}
+ return ret;
}
- return d_skolem_body[f];
+ return it->second;
}
bool Skolemize::isInductionTerm(Node n)
@@ -332,7 +370,7 @@ bool Skolemize::isInductionTerm(Node n)
const DType& dt = tn.getDType();
return !dt.isCodatatype();
}
- if (options::intWfInduction() && n.getType().isInteger())
+ if (options::intWfInduction() && tn.isInteger())
{
return true;
}
@@ -364,6 +402,8 @@ bool Skolemize::printSkolemization(std::ostream& out)
return printed;
}
+bool Skolemize::isProofEnabled() const { return d_epg != nullptr; }
+
} /* CVC4::theory::quantifiers namespace */
} /* CVC4::theory namespace */
} /* CVC4 namespace */
diff --git a/src/theory/quantifiers/skolemize.h b/src/theory/quantifiers/skolemize.h
index 6db3f6215..4469fe851 100644
--- a/src/theory/quantifiers/skolemize.h
+++ b/src/theory/quantifiers/skolemize.h
@@ -24,6 +24,7 @@
#include "expr/node.h"
#include "expr/type_node.h"
#include "theory/quantifiers/quant_util.h"
+#include "theory/trust_node.h"
namespace CVC4 {
@@ -63,15 +64,16 @@ class Skolemize
typedef context::CDHashMap<Node, Node, NodeHashFunction> NodeNodeMap;
public:
- Skolemize(QuantifiersEngine* qe, context::UserContext* u);
+ Skolemize(QuantifiersEngine* qe,
+ context::UserContext* u,
+ ProofNodeManager* pnm);
~Skolemize() {}
/** skolemize quantified formula q
- * If the return value ret of this function
- * is non-null, then ret is a new skolemization lemma
- * we generated for q. These lemmas are constructed
- * once per user-context.
+ * If the return value ret of this function is non-null, then ret is a trust
+ * node corresponding to a new skolemization lemma we generated for q. These
+ * lemmas are constructed once per user-context.
*/
- Node process(Node q);
+ TrustNode process(Node q);
/** get skolem constants for quantified formula q */
bool getSkolemConstants(Node q, std::vector<Node>& skolems);
/** get the i^th skolem constant for quantified formula q */
@@ -119,6 +121,8 @@ class Skolemize
bool printSkolemization(std::ostream& out);
private:
+ /** Are proofs enabled? */
+ bool isProofEnabled() const;
/** get self selectors
* For datatype constructor dtc with type dt,
* this collects the set of datatype selector applications,
@@ -139,6 +143,10 @@ class Skolemize
d_skolem_constants;
/** map from quantified formulas to their skolemized body */
std::unordered_map<Node, Node, NodeHashFunction> d_skolem_body;
+ /** Pointer to the proof node manager */
+ ProofNodeManager* d_pnm;
+ /** Eager proof generator for skolemization lemmas */
+ std::unique_ptr<EagerProofGenerator> d_epg;
};
} /* CVC4::theory::quantifiers namespace */
diff --git a/src/theory/quantifiers_engine.cpp b/src/theory/quantifiers_engine.cpp
index cceb04d9f..7f0b46c99 100644
--- a/src/theory/quantifiers_engine.cpp
+++ b/src/theory/quantifiers_engine.cpp
@@ -30,7 +30,8 @@ using namespace CVC4::kind;
namespace CVC4 {
namespace theory {
-QuantifiersEngine::QuantifiersEngine(TheoryEngine* te, DecisionManager& dm,
+QuantifiersEngine::QuantifiersEngine(TheoryEngine* te,
+ DecisionManager& dm,
ProofNodeManager* pnm)
: d_te(te),
d_context(te->getSatContext()),
@@ -49,7 +50,7 @@ QuantifiersEngine::QuantifiersEngine(TheoryEngine* te, DecisionManager& dm,
d_sygus_tdb(nullptr),
d_quant_attr(new quantifiers::QuantAttributes(this)),
d_instantiate(new quantifiers::Instantiate(this, d_userContext, pnm)),
- d_skolemize(new quantifiers::Skolemize(this, d_userContext)),
+ d_skolemize(new quantifiers::Skolemize(this, d_userContext, pnm)),
d_term_enum(new quantifiers::TermEnumeration),
d_conflict_c(d_context, false),
d_quants_prereg(d_userContext),
@@ -809,16 +810,16 @@ void QuantifiersEngine::assertQuantifier( Node f, bool pol ){
}
if( !pol ){
// do skolemization
- Node lem = d_skolemize->process(f);
+ TrustNode lem = d_skolemize->process(f);
if (!lem.isNull())
{
if (Trace.isOn("quantifiers-sk-debug"))
{
- Node slem = Rewriter::rewrite(lem);
+ Node slem = Rewriter::rewrite(lem.getNode());
Trace("quantifiers-sk-debug")
<< "Skolemize lemma : " << slem << std::endl;
}
- getOutputChannel().lemma(
+ getOutputChannel().trustedLemma(
lem, LemmaProperty::PREPROCESS | LemmaProperty::NEEDS_JUSTIFY);
}
return;
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