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Code Issues 15 Releases 21 Activity

Move simplification rule to tableau

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This moves the rule “exists () (F) === F” to the simplification rule
tableau.
This commit is contained in:
Patrick Lühne 2018-03-25 19:42:55 +02:00
parent 827d6e40fe
commit 107dae7287
Signed by: patrick
GPG Key ID: 05F3611E97A70ABF
1 changed files with 23 additions and 6 deletions
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29
src/anthem/Simplification.cpp
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@ -124,6 +124,28 @@ SimplificationResult simplify(ast::Formula &formula)
////////////////////////////////////////////////////////////////////////////////////////////////////
struct SimplificationRuleExistsWithoutQuantifiedVariables
{
static constexpr const auto Description = "exists () (F) === F";
static SimplificationResult apply(ast::Formula &formula)
{
if (!formula.is<ast::Exists>())
return SimplificationResult::Unchanged;
auto &exists = formula.get<ast::Exists>();
if (!exists.variables.empty())
return SimplificationResult::Unchanged;
formula = std::move(exists.argument);
return SimplificationResult::Simplified;
}
};
////////////////////////////////////////////////////////////////////////////////////////////////////
struct SimplificationRuleTrivialAssignmentInExists
{
static constexpr const auto Description = "exists X (X = Y) === #true";
@ -304,12 +326,7 @@ void simplify(ast::Exists &exists, ast::Formula &formula)
SimplificationRuleTrivialExists::apply(formula);
SimplificationRuleOneElementConjunction::apply(exists.argument);
// If there are still remaining variables, simplification is over
if (!exists.variables.empty())
return;
// If there is more than one element in the conjunction, replace the input formula with the conjunction
formula = std::move(exists.argument);
SimplificationRuleExistsWithoutQuantifiedVariables::apply(formula);
}
////////////////////////////////////////////////////////////////////////////////////////////////////