diff --git a/src/storage/DeterministicModelBisimulationDecomposition.cpp b/src/storage/DeterministicModelBisimulationDecomposition.cpp
index 6c8641211..08c11a2f2 100644
--- a/src/storage/DeterministicModelBisimulationDecomposition.cpp
+++ b/src/storage/DeterministicModelBisimulationDecomposition.cpp
@@ -615,7 +615,7 @@ namespace storm {
             }
             for (auto const& expressionFormula : atomicExpressionFormulas) {
                 std::stringstream stream;
-                stream << expressionFormula;
+                stream << *expressionFormula;
                 labelsToRespect.insert(stream.str());
             }
             respectedAtomicPropositions = labelsToRespect;
@@ -722,7 +722,7 @@ namespace storm {
         
         template<typename ValueType>
         template<typename ModelType>
-        void DeterministicModelBisimulationDecomposition<ValueType>::buildQuotient(ModelType const& model, boost::optional<std::set<std::string>> const& selectedAtomicPropositions, Partition const& partition, BisimulationType bisimulationType, bool keepRewards) {
+        void DeterministicModelBisimulationDecomposition<ValueType>::buildQuotient(ModelType const& model, std::set<std::string> const& selectedAtomicPropositions, Partition const& partition, BisimulationType bisimulationType, bool keepRewards) {
             // In order to create the quotient model, we need to construct
             // (a) the new transition matrix,
             // (b) the new labeling,
@@ -733,7 +733,7 @@ namespace storm {
             
             // Prepare the new state labeling for (b).
             storm::models::AtomicPropositionsLabeling newLabeling(this->size(), model.getStateLabeling().getNumberOfAtomicPropositions());
-            std::set<std::string> atomicPropositionsSet = selectedAtomicPropositions ? selectedAtomicPropositions.get() : model.getStateLabeling().getAtomicPropositions();
+            std::set<std::string> atomicPropositionsSet = selectedAtomicPropositions;
             atomicPropositionsSet.insert("init");
             std::vector<std::string> atomicPropositions = std::vector<std::string>(atomicPropositionsSet.begin(), atomicPropositionsSet.end());
             for (auto const& ap : atomicPropositions) {
@@ -839,7 +839,7 @@ namespace storm {
         
         template<typename ValueType>
         template<typename ModelType>
-        void DeterministicModelBisimulationDecomposition<ValueType>::partitionRefinement(ModelType const& model, boost::optional<std::set<std::string>> const& atomicPropositions, storm::storage::SparseMatrix<ValueType> const& backwardTransitions, Partition& partition, BisimulationType bisimulationType, bool keepRewards, bool buildQuotient) {
+        void DeterministicModelBisimulationDecomposition<ValueType>::partitionRefinement(ModelType const& model, std::set<std::string> const& atomicPropositions, storm::storage::SparseMatrix<ValueType> const& backwardTransitions, Partition& partition, BisimulationType bisimulationType, bool keepRewards, bool buildQuotient) {
             std::chrono::high_resolution_clock::time_point totalStart = std::chrono::high_resolution_clock::now();
             
             // Initially, all blocks are potential splitter, so we insert them in the splitterQueue.
diff --git a/src/storage/DeterministicModelBisimulationDecomposition.h b/src/storage/DeterministicModelBisimulationDecomposition.h
index 255e2c22a..eae63f442 100644
--- a/src/storage/DeterministicModelBisimulationDecomposition.h
+++ b/src/storage/DeterministicModelBisimulationDecomposition.h
@@ -413,8 +413,7 @@ namespace storm {
              * getQuotient().
              *
              * @param model The model on whose state space to compute the coarses strong bisimulation relation.
-             * @param atomicPropositions The set of atomic propositions that the bisimulation considers. If not given,
-             * all atomic propositions are considered.
+             * @param atomicPropositions The set of atomic propositions that the bisimulation considers.
              * @param backwardTransitions The backward transitions of the model.
              * @param The initial partition.
              * @param bisimulationType The kind of bisimulation that is to be computed.
@@ -422,7 +421,7 @@ namespace storm {
              * method.
              */
             template<typename ModelType>
-            void partitionRefinement(ModelType const& model, boost::optional<std::set<std::string>> const& atomicPropositions, storm::storage::SparseMatrix<ValueType> const& backwardTransitions, Partition& partition, BisimulationType bisimulationType, bool keepRewards, bool buildQuotient);
+            void partitionRefinement(ModelType const& model, std::set<std::string> const& atomicPropositions, storm::storage::SparseMatrix<ValueType> const& backwardTransitions, Partition& partition, BisimulationType bisimulationType, bool keepRewards, bool buildQuotient);
             
             /*!
              * Refines the partition based on the provided splitter. After calling this method all blocks are stable
@@ -466,15 +465,14 @@ namespace storm {
              *
              * @param model The model whose state space was used for computing the equivalence classes. This is used for
              * determining the transitions of each equivalence class.
-             * @param selectedAtomicPropositions The set of atomic propositions that was considered by the bisimulation. The
-             * quotient will only have these atomic propositions. If not given, all atomic propositions will be
-             * considered.
+             * @param selectedAtomicPropositions The set of atomic propositions that was considered by the bisimulation.
+             * The quotient will only have these atomic propositions.
              * @param partition The previously computed partition. This is used for quickly retrieving the block of a
              * state.
              * @param bisimulationType The kind of bisimulation that is to be computed.
              */
             template<typename ModelType>
-            void buildQuotient(ModelType const& model, boost::optional<std::set<std::string>> const& selectedAtomicPropositions, Partition const& partition, BisimulationType bisimulationType, bool keepRewards);
+            void buildQuotient(ModelType const& model, std::set<std::string> const& selectedAtomicPropositions, Partition const& partition, BisimulationType bisimulationType, bool keepRewards);
 
             /*!
              * Creates the measure-driven initial partition for reaching psi states from phi states.