diff --git a/src/search/cartesian_abstractions/flaw.cc b/src/search/cartesian_abstractions/flaw.cc
index 39cee53f2..c2edc5175 100644
--- a/src/search/cartesian_abstractions/flaw.cc
+++ b/src/search/cartesian_abstractions/flaw.cc
@@ -9,7 +9,7 @@
 using namespace std;
 
 namespace cartesian_abstractions {
-const FlawedState FlawedState::no_state = FlawedState(-1, -1u, {});
+const FlawedState FlawedState::no_state = FlawedState(-1, UNDEFINED_COST, {});
 
 bool FlawedStates::is_consistent() const {
     return flawed_states_queue.size() == static_cast<int>(flawed_states.size());
@@ -53,7 +53,7 @@ FlawedState FlawedStates::pop_random_flawed_state_and_clear(utils::RandomNumberG
     vector<StateID> conc_states = move(random_bucket->second);
     clear();
     assert(is_consistent());
-    return FlawedState(abstract_state_id, -1u, move(conc_states));
+    return FlawedState(abstract_state_id, UNDEFINED_COST, move(conc_states));
 }
 
 int FlawedStates::num_abstract_states() const {
diff --git a/src/search/cartesian_abstractions/types.h b/src/search/cartesian_abstractions/types.h
index b50bc794f..0fa4bdd8b 100644
--- a/src/search/cartesian_abstractions/types.h
+++ b/src/search/cartesian_abstractions/types.h
@@ -25,11 +25,11 @@ using Loops = std::vector<int>;
 using Solution = std::deque<Transition>;
 using Transitions = std::vector<Transition>;
 
-const int UNDEFINED = -1;
-
 // Positive infinity. The name "INFINITY" is taken by an ISO C99 macro.
 const int INF = std::numeric_limits<int>::max();
+const int UNDEFINED = -1;
 const Cost INF_COSTS = std::numeric_limits<Cost>::max();
+const Cost UNDEFINED_COST = std::numeric_limits<Cost>::max() - 1;
 }
 
 #endif