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Complete theory_finite_set.h header and implement finite set theory solver (#7976)

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* Initial plan

* Implement theory_finite_set header and implementation

Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com>

* Add theory registration to smt_setup

Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com>

* Update theory_finite_set.cpp

* Refactor membership_atoms and add elements list

Renamed membership_atoms to membership_elements and added elements list.

* Change membership elements to use enode type

* Update theory_finite_set.cpp

* Fix typo in internalize_atom function

* Update theory_finite_set.cpp

* Refactor final_check_eh by removing comments

Removed redundant comments and cleaned up code.

* Add m_lemmas member to theory_finite_set class

* Improve clause management and instantiation logic

Refactor clause handling and instantiate logic in finite set theory.

* Add friend class declaration for testing

* Add placeholder methods for lemma instantiation

Added placeholder methods for lemma instantiation.

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com>
Co-authored-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Copilot 2025-10-15 14:55:08 +02:00 • committed by GitHub
parent 7446112fbe
commit b4d41ffe81
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5 changed files with 248 additions and 2 deletions
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1
src/smt/CMakeLists.txt
View file

@ -57,6 +57,7 @@ z3_add_component(smt
theory_char.cpp
theory_datatype.cpp
theory_dense_diff_logic.cpp
theory_finite_set.cpp
theory_diff_logic.cpp
theory_dl.cpp
theory_dummy.cpp

6
src/smt/smt_setup.cpp
View file

@ -40,6 +40,7 @@ Revision History:
#include "smt/theory_pb.h"
#include "smt/theory_fpa.h"
#include "smt/theory_polymorphism.h"
#include "smt/theory_finite_set.h"
namespace smt {
@ -784,6 +785,10 @@ namespace smt {
m_context.register_plugin(alloc(smt::theory_char, m_context));
}
void setup::setup_finite_set() {
m_context.register_plugin(alloc(smt::theory_finite_set, m_context));
}
void setup::setup_special_relations() {
m_context.register_plugin(alloc(smt::theory_special_relations, m_context, m_manager));
}
@ -807,6 +812,7 @@ namespace smt {
setup_dl();
setup_seq_str(st);
setup_fpa();
setup_finite_set();
setup_special_relations();
setup_polymorphism();
setup_relevancy(st);

1
src/smt/smt_setup.h
View file

@ -102,6 +102,7 @@ namespace smt {
void setup_seq_str(static_features const & st);
void setup_seq();
void setup_char();
void setup_finite_set();
void setup_card();
void setup_sls();
void setup_i_arith();

209
src/smt/theory_finite_set.cpp Normal file
View file

@ -0,0 +1,209 @@
/*++
Copyright (c) 2025 Microsoft Corporation
Module Name:
theory_finite_set.cpp
Abstract:
Theory solver for finite sets.
Implements axiom schemas for finite set operations.
Author:
GitHub Copilot Agent 2025
Revision History:
--*/
#include "smt/theory_finite_set.h"
#include "smt/smt_context.h"
#include "smt/smt_model_generator.h"
#include "ast/ast_pp.h"
namespace smt {
theory_finite_set::theory_finite_set(context& ctx):
theory(ctx, ctx.get_manager().mk_family_id("finite_set")),
u(m),
m_axioms(m)
{
// Setup the add_clause callback for axioms
std::function<void(expr_ref_vector const &)> add_clause_fn =
[this](expr_ref_vector const& clause) {
this->m_lemmas.push_back(clause);
};
m_axioms.set_add_clause(add_clause_fn);
}
bool theory_finite_set::internalize_atom(app * atom, bool gate_ctx) {
TRACE("finite_set", tout << "internalize_atom: " << mk_pp(atom, m) << "\n";);
internalize_term(atom);
// Track membership elements (set.in)
expr* elem = nullptr, *set = nullptr;
if (u.is_in(atom, elem, set)) {
auto n = ctx.get_enode(elem);
if (!m_elements.contains(n)) {
m_elements.insert(n);
ctx.push_trail(insert_obj_trail(n));
}
}
return true;
}
bool theory_finite_set::internalize_term(app * term) {
TRACE("finite_set", tout << "internalize_term: " << mk_pp(term, m) << "\n";);
// Internalize all arguments first
for (expr* arg : *term)
ctx.internalize(arg, false);
// Create boolean variable for Boolean terms
if (m.is_bool(term) && !ctx.b_internalized(term)) {
bool_var bv = ctx.mk_bool_var(term);
ctx.set_var_theory(bv, get_id());
}
// Create enode for the term if needed
enode* e = nullptr;
if (ctx.e_internalized(term))
e = ctx.get_enode(term);
else
e = ctx.mk_enode(term, false, m.is_bool(term), true);
// Attach theory variable if this is a set
if (!is_attached_to_var(e))
ctx.attach_th_var(e, this, mk_var(e));
return true;
}
void theory_finite_set::new_eq_eh(theory_var v1, theory_var v2) {
TRACE("finite_set", tout << "new_eq_eh: v" << v1 << " = v" << v2 << "\n";);
// When two sets are equal, propagate membership constraints
// This is handled by congruence closure, so no additional work needed here
}
void theory_finite_set::new_diseq_eh(theory_var v1, theory_var v2) {
TRACE("finite_set", tout << "new_diseq_eh: v" << v1 << " != v" << v2 << "\n";);
// Disequalities could trigger extensionality axioms
// For now, we rely on the final_check to handle this
}
final_check_status theory_finite_set::final_check_eh() {
TRACE("finite_set", tout << "final_check_eh\n";);
// walk all parents of elem in congruence table.
// if a parent is of the form elem' in S u T, or similar.
// create clauses for elem in S u T.
expr* elem1 = nullptr, *set1 = nullptr;
m_lemmas.reset();
for (auto elem : m_elements) {
for (auto p : enode::parents(elem)) {
if (!u.is_in(p->get_expr(), elem1, set1))
continue;
if (elem->get_root() != p->get_arg(0)->get_root())
continue; // elem is then equal to set1 but not elem1. This is a different case.
for (auto sib : *p->get_arg(1))
instantiate_axioms(elem->get_expr(), sib->get_expr());
}
}
if (instantiate_false_lemma())
return FC_CONTINUE;
if (instantiate_unit_propagation())
return FC_CONTINUE;
if (instantiate_free_lemma())
return FC_CONTINUE;
return FC_DONE;
}
void theory_finite_set::instantiate_axioms(expr* elem, expr* set) {
TRACE("finite_set", tout << "instantiate_axioms: " << mk_pp(elem, m) << " in " << mk_pp(set, m) << "\n";);
// Instantiate appropriate axiom based on set structure
if (u.is_empty(set)) {
m_axioms.in_empty_axiom(elem);
}
else if (u.is_singleton(set)) {
m_axioms.in_singleton_axiom(elem, set);
}
else if (u.is_union(set)) {
m_axioms.in_union_axiom(elem, set);
}
else if (u.is_intersect(set)) {
m_axioms.in_intersect_axiom(elem, set);
}
else if (u.is_difference(set)) {
m_axioms.in_difference_axiom(elem, set);
}
else if (u.is_range(set)) {
m_axioms.in_range_axiom(elem, set);
}
else if (u.is_map(set)) {
m_axioms.in_map_axiom(elem, set);
m_axioms.in_map_image_axiom(elem, set);
}
else if (u.is_select(set)) {
m_axioms.in_select_axiom(elem, set);
}
// Instantiate size axioms for singleton sets
// TODO, such axioms don't belong here
if (u.is_singleton(set)) {
m_axioms.size_singleton_axiom(set);
}
}
void theory_finite_set::add_clause(expr_ref_vector const& clause) {
TRACE("finite_set",
tout << "add_clause: " << clause << "\n");
// Convert expressions to literals and assert the clause
literal_vector lits;
for (expr* e : clause) {
ctx.internalize(e, false);
literal lit = ctx.get_literal(lit_expr);
lits.push_back(lit);
}
if (!lits.empty()) {
scoped_trace_stream _sts(*this, lits);
ctx.mk_th_axiom(get_id(), lits);
}
}
theory * theory_finite_set::mk_fresh(context * new_ctx) {
return alloc(theory_finite_set, *new_ctx);
}
void theory_finite_set::display(std::ostream & out) const {
out << "theory_finite_set:\n";
}
void theory_finite_set::init_model(model_generator & mg) {
TRACE("finite_set", tout << "init_model\n";);
// Model generation will use default interpretation for sets
// The model will be constructed based on the membership literals that are true
}
model_value_proc * theory_finite_set::mk_value(enode * n, model_generator & mg) {
TRACE("finite_set", tout << "mk_value: " << mk_pp(n->get_expr(), m) << "\n";);
// For now, return nullptr to use default model construction
// A complete implementation would construct explicit set values
// based on true membership literals
return nullptr;
}
void theory_finite_set::instantiate_false_lemma() {}
void theory_finite_set::instantiate_unit_propagation() {}
void theory_finite_set::instantiate_free_lemma() {}
} // namespace smt

31
src/smt/theory_finite_set.h
View file

@ -86,12 +86,41 @@ theory_finite_set.cpp.
#include "ast/ast.h"
#include "ast/ast_pp.h"
#include "ast/finite_set_decl_plugin.h"
#include "ast/rewriter/finite_set_axioms.h"
#include "smt/smt_theory.h"
namespace smt {
class theory_finite_set : public theory {
friend class theory_finite_set_test;
finite_set_util u;
finite_set_axioms m_axioms;
obj_hashtable<enode> m_elements; // set of all 'x' where there is an 'x in S' atom
vector<expr_ref_vector> m_lemmas;
protected:
// Override relevant methods from smt::theory
bool internalize_atom(app * atom, bool gate_ctx) override;
bool internalize_term(app * term) override;
void new_eq_eh(theory_var v1, theory_var v2) override;
void new_diseq_eh(theory_var v1, theory_var v2) override;
final_check_status final_check_eh() override;
theory * mk_fresh(context * new_ctx) override;
char const * get_name() const override { return "finite_set"; }
void display(std::ostream & out) const override;
void init_model(model_generator & mg) override;
model_value_proc * mk_value(enode * n, model_generator & mg) override;
// Helper methods for axiom instantiation
void instantiate_axioms(expr* elem, expr* set);
void add_clause(expr_ref_vector const& clause);
void instantiate_false_lemma();
void instantiate_unit_propagation();
void instantiate_free_lemma();
public:
theory_finite_set(ast_manager & m);
theory_finite_set(context& ctx);
~theory_finite_set() override {}
};