diff --git a/io-hotmoka-node-disk/src/main/java/io/hotmoka/node/disk/internal/DiskNodeImpl.java b/io-hotmoka-node-disk/src/main/java/io/hotmoka/node/disk/internal/DiskNodeImpl.java
index 798862daa..2e7da8a92 100644
--- a/io-hotmoka-node-disk/src/main/java/io/hotmoka/node/disk/internal/DiskNodeImpl.java
+++ b/io-hotmoka-node-disk/src/main/java/io/hotmoka/node/disk/internal/DiskNodeImpl.java
@@ -37,7 +37,7 @@
  * nor transactions. Updates are stored in files, rather than in an external database.
  */
 @ThreadSafe
-public class DiskNodeImpl extends AbstractLocalNode<DiskNodeImpl, DiskNodeConfig, DiskStore> implements DiskNode {
+public class DiskNodeImpl extends AbstractLocalNode<DiskNodeConfig, DiskStore> implements DiskNode {
 
 	/**
 	 * The mempool where transaction requests are stored and eventually executed.
diff --git a/io-hotmoka-node-disk/src/main/java/io/hotmoka/node/disk/internal/DiskStore.java b/io-hotmoka-node-disk/src/main/java/io/hotmoka/node/disk/internal/DiskStore.java
index 93248412d..f92b970ee 100644
--- a/io-hotmoka-node-disk/src/main/java/io/hotmoka/node/disk/internal/DiskStore.java
+++ b/io-hotmoka-node-disk/src/main/java/io/hotmoka/node/disk/internal/DiskStore.java
@@ -54,7 +54,7 @@
  * while the histories are kept in RAM.
  */
 @Immutable
-class DiskStore extends AbstractStore<DiskStore, DiskNodeImpl> {
+class DiskStore extends AbstractStore<DiskStore> {
 
 	/**
 	 * The path where the database of the store gets created.
diff --git a/io-hotmoka-node-local-api/src/main/java/io/hotmoka/node/local/api/CheckableStore.java b/io-hotmoka-node-local-api/src/main/java/io/hotmoka/node/local/api/CheckableStore.java
index a17043bae..07554d76b 100644
--- a/io-hotmoka-node-local-api/src/main/java/io/hotmoka/node/local/api/CheckableStore.java
+++ b/io-hotmoka-node-local-api/src/main/java/io/hotmoka/node/local/api/CheckableStore.java
@@ -21,7 +21,7 @@
  * back and forth in time. Different moments of the store are identifies by state
  * identifiers, that can be checked out when needed.
  */
-public interface CheckableStore<S extends CheckableStore<S, N>, N extends LocalNode<?>> extends Store<S,N> {
+public interface CheckableStore<S extends CheckableStore<S>> extends Store<S> {
 
 	/**
 	 * Yields a unique identifier for the current state of this store.
diff --git a/io-hotmoka-node-local-api/src/main/java/io/hotmoka/node/local/api/LocalNode.java b/io-hotmoka-node-local-api/src/main/java/io/hotmoka/node/local/api/LocalNode.java
index 9ef465f47..8fac73823 100644
--- a/io-hotmoka-node-local-api/src/main/java/io/hotmoka/node/local/api/LocalNode.java
+++ b/io-hotmoka-node-local-api/src/main/java/io/hotmoka/node/local/api/LocalNode.java
@@ -27,6 +27,6 @@
  * @param <S> the type of the store of the node
  */
 @ThreadSafe
-public interface LocalNode<C extends LocalNodeConfig<?,?>> extends Node {
+public interface LocalNode<C extends LocalNodeConfig<C,?>> extends Node {
 	C getLocalConfig() throws NodeException;
 }
\ No newline at end of file
diff --git a/io-hotmoka-node-local-api/src/main/java/io/hotmoka/node/local/api/Store.java b/io-hotmoka-node-local-api/src/main/java/io/hotmoka/node/local/api/Store.java
index 38283dce8..a231fad6c 100644
--- a/io-hotmoka-node-local-api/src/main/java/io/hotmoka/node/local/api/Store.java
+++ b/io-hotmoka-node-local-api/src/main/java/io/hotmoka/node/local/api/Store.java
@@ -32,7 +32,7 @@
  * be used concurrently for executing more requests.
  */
 @ThreadSafe
-public interface Store<S extends Store<S, N>, N extends LocalNode<?>> extends AutoCloseable {
+public interface Store<S extends Store<S>> extends AutoCloseable {
 
 	/**
 	 * Yields the response of the transaction having the given reference.
diff --git a/io-hotmoka-node-local-api/src/main/java/io/hotmoka/node/local/api/StoreTransaction.java b/io-hotmoka-node-local-api/src/main/java/io/hotmoka/node/local/api/StoreTransaction.java
index c09e71788..40a3a1282 100644
--- a/io-hotmoka-node-local-api/src/main/java/io/hotmoka/node/local/api/StoreTransaction.java
+++ b/io-hotmoka-node-local-api/src/main/java/io/hotmoka/node/local/api/StoreTransaction.java
@@ -48,7 +48,7 @@
  * its hash is held in the node, if consensus is needed. Stores must be thread-safe, since they can
  * be used concurrently for executing more requests.
  */
-public interface StoreTransaction<S extends Store<S, ?>> {
+public interface StoreTransaction<S extends Store<S>> {
 
 	/**
 	 * Yields the store from which this transaction begun.
diff --git a/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractLocalNode.java b/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractLocalNode.java
index 6d7e9c48a..a2a0e99c7 100644
--- a/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractLocalNode.java
+++ b/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractLocalNode.java
@@ -30,7 +30,7 @@
  * @param <S> the type of the store of the node
  */
 @ThreadSafe
-public abstract class AbstractLocalNode<N extends AbstractLocalNode<N,C,S>, C extends LocalNodeConfig<?,?>, S extends AbstractStore<S, N>> extends AbstractLocalNodeImpl<N,C,S> {
+public abstract class AbstractLocalNode<C extends LocalNodeConfig<C,?>, S extends AbstractStore<S>> extends AbstractLocalNodeImpl<C,S> {
 
 	/**
 	 * Builds a node with a brand new, empty store.
diff --git a/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractStore.java b/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractStore.java
index 764a8c8f0..f42efd539 100644
--- a/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractStore.java
+++ b/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractStore.java
@@ -33,7 +33,7 @@
 import io.hotmoka.node.local.api.StoreTransaction;
 
 @Immutable
-public abstract class AbstractStore<S extends AbstractStore<S, N>, N extends AbstractLocalNode<N, ?, S>> implements Store<S, N> {
+public abstract class AbstractStore<S extends AbstractStore<S>> implements Store<S> {
 
 	/**
 	 * Cached recent transactions whose requests that have had their signature checked.
@@ -92,7 +92,7 @@ protected AbstractStore(ExecutorService executors, ConsensusConfig<?,?> consensu
 		this.inflation = OptionalLong.empty();
 	}
 
-	protected AbstractStore(AbstractStore<S, N> toClone) {
+	protected AbstractStore(AbstractStore<S> toClone) {
 		this.executors = toClone.executors;
 		this.hasher = toClone.hasher;
 		this.checkedSignatures = toClone.checkedSignatures;
@@ -104,7 +104,7 @@ protected AbstractStore(AbstractStore<S, N> toClone) {
 		this.inflation = toClone.inflation;
 	}
 
-	protected AbstractStore(AbstractStore<S, N> toClone, LRUCache<TransactionReference, Boolean> checkedSignatures, LRUCache<TransactionReference, EngineClassLoader> classLoaders, ConsensusConfig<?,?> consensus, Optional<BigInteger> gasPrice, OptionalLong inflation) {
+	protected AbstractStore(AbstractStore<S> toClone, LRUCache<TransactionReference, Boolean> checkedSignatures, LRUCache<TransactionReference, EngineClassLoader> classLoaders, ConsensusConfig<?,?> consensus, Optional<BigInteger> gasPrice, OptionalLong inflation) {
 		this.executors = toClone.executors;
 		this.hasher = toClone.hasher;
 		this.checkedSignatures = checkedSignatures; //new LRUCache<>(checkedSignatures);
diff --git a/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractStoreTransaction.java b/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractStoreTransaction.java
index d4ef3cfe9..0de07f415 100644
--- a/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractStoreTransaction.java
+++ b/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractStoreTransaction.java
@@ -122,7 +122,7 @@
  * its hash is held in the node, if consensus is needed. Stores must be thread-safe, since they can
  * be used concurrently for executing more requests.
  */
-public abstract class AbstractStoreTransaction<S extends AbstractStore<S, ?>> implements StoreTransaction<S> {
+public abstract class AbstractStoreTransaction<S extends AbstractStore<S>> implements StoreTransaction<S> {
 	private final static Logger LOGGER = Logger.getLogger(AbstractStoreTransaction.class.getName());
 	private final S store;
 
diff --git a/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractTrieBasedStore.java b/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractTrieBasedStore.java
index d1c0eb3f4..3c981b18a 100644
--- a/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractTrieBasedStore.java
+++ b/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractTrieBasedStore.java
@@ -70,7 +70,7 @@
  * This class is meant to be subclassed by specifying where errors, requests and histories are kept.
  */
 @Immutable
-public abstract class AbstractTrieBasedStore<S extends AbstractTrieBasedStore<S, N>, N extends AbstractLocalNode<N, ?, S>> extends AbstractStore<S, N> {
+public abstract class AbstractTrieBasedStore<S extends AbstractTrieBasedStore<S>> extends AbstractStore<S> {
 
 	/**
 	 * The Xodus environment that holds the store.
@@ -202,7 +202,7 @@ protected AbstractTrieBasedStore(ExecutorService executors, ConsensusConfig<?,?>
     	}
     }
 
-    protected AbstractTrieBasedStore(AbstractTrieBasedStore<S, N> toClone) {
+    protected AbstractTrieBasedStore(AbstractTrieBasedStore<S> toClone) {
     	super(toClone);
 
     	this.env = toClone.env;
@@ -218,7 +218,7 @@ protected AbstractTrieBasedStore(AbstractTrieBasedStore<S, N> toClone) {
     	this.rootOfRequests = toClone.rootOfRequests;
     }
 
-    protected AbstractTrieBasedStore(AbstractTrieBasedStore<S, N> toClone, LRUCache<TransactionReference, Boolean> checkedSignatures, LRUCache<TransactionReference, EngineClassLoader> classLoaders, ConsensusConfig<?,?> consensus, Optional<BigInteger> gasPrice, OptionalLong inflation, Optional<byte[]> rootOfResponses, Optional<byte[]> rootOfInfo, Optional<byte[]> rootOfErrors, Optional<byte[]> rootOfHistories, Optional<byte[]> rootOfRequests) {
+    protected AbstractTrieBasedStore(AbstractTrieBasedStore<S> toClone, LRUCache<TransactionReference, Boolean> checkedSignatures, LRUCache<TransactionReference, EngineClassLoader> classLoaders, ConsensusConfig<?,?> consensus, Optional<BigInteger> gasPrice, OptionalLong inflation, Optional<byte[]> rootOfResponses, Optional<byte[]> rootOfInfo, Optional<byte[]> rootOfErrors, Optional<byte[]> rootOfHistories, Optional<byte[]> rootOfRequests) {
     	super(toClone, checkedSignatures, classLoaders, consensus, gasPrice, inflation);
 
     	this.env = toClone.env;
diff --git a/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractTrieBasedStoreTransaction.java b/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractTrieBasedStoreTransaction.java
index 74d757177..a26bf57d7 100644
--- a/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractTrieBasedStoreTransaction.java
+++ b/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/AbstractTrieBasedStoreTransaction.java
@@ -19,7 +19,7 @@
 import io.hotmoka.xodus.ExodusException;
 import io.hotmoka.xodus.env.Transaction;
 
-public abstract class AbstractTrieBasedStoreTransaction<S extends AbstractTrieBasedStore<S, ?>> extends AbstractStoreTransaction<S> {
+public abstract class AbstractTrieBasedStoreTransaction<S extends AbstractTrieBasedStore<S>> extends AbstractStoreTransaction<S> {
 
 	/**
 	 * The Xodus transaction where the updates get recorded.
diff --git a/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/internal/AbstractLocalNodeImpl.java b/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/internal/AbstractLocalNodeImpl.java
index 72ddd6221..06c9148ec 100644
--- a/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/internal/AbstractLocalNodeImpl.java
+++ b/io-hotmoka-node-local/src/main/java/io/hotmoka/node/local/internal/AbstractLocalNodeImpl.java
@@ -80,7 +80,6 @@
 import io.hotmoka.node.api.updates.Update;
 import io.hotmoka.node.api.values.StorageReference;
 import io.hotmoka.node.api.values.StorageValue;
-import io.hotmoka.node.local.AbstractLocalNode;
 import io.hotmoka.node.local.AbstractStore;
 import io.hotmoka.node.local.LRUCache;
 import io.hotmoka.node.local.api.LocalNode;
@@ -94,7 +93,7 @@
  * @param <S> the type of the store of the node
  */
 @ThreadSafe
-public abstract class AbstractLocalNodeImpl<N extends AbstractLocalNode<N,C,S>, C extends LocalNodeConfig<?,?>, S extends AbstractStore<S, N>> extends AbstractAutoCloseableWithLockAndOnCloseHandlers<ClosedNodeException> implements LocalNode<C> {
+public abstract class AbstractLocalNodeImpl<C extends LocalNodeConfig<C,?>, S extends AbstractStore<S>> extends AbstractAutoCloseableWithLockAndOnCloseHandlers<ClosedNodeException> implements LocalNode<C> {
 
 	/**
 	 * The manager of the subscriptions to the events occurring in this node.
diff --git a/io-hotmoka-node-tendermint/src/main/java/io/hotmoka/node/tendermint/internal/TendermintNodeImpl.java b/io-hotmoka-node-tendermint/src/main/java/io/hotmoka/node/tendermint/internal/TendermintNodeImpl.java
index c074661b9..4c3ea830a 100644
--- a/io-hotmoka-node-tendermint/src/main/java/io/hotmoka/node/tendermint/internal/TendermintNodeImpl.java
+++ b/io-hotmoka-node-tendermint/src/main/java/io/hotmoka/node/tendermint/internal/TendermintNodeImpl.java
@@ -55,7 +55,7 @@
  * its state in a transactional database implemented by the {@link TendermintStore} class.
  */
 @ThreadSafe
-public class TendermintNodeImpl extends AbstractLocalNode<TendermintNodeImpl, TendermintNodeConfig, TendermintStore> implements TendermintNode {
+public class TendermintNodeImpl extends AbstractLocalNode<TendermintNodeConfig, TendermintStore> implements TendermintNode {
 
 	private final static Logger LOGGER = Logger.getLogger(TendermintNodeImpl.class.getName());
 
diff --git a/io-hotmoka-node-tendermint/src/main/java/io/hotmoka/node/tendermint/internal/TendermintStore.java b/io-hotmoka-node-tendermint/src/main/java/io/hotmoka/node/tendermint/internal/TendermintStore.java
index 28beb1eb3..8bc4bc08f 100644
--- a/io-hotmoka-node-tendermint/src/main/java/io/hotmoka/node/tendermint/internal/TendermintStore.java
+++ b/io-hotmoka-node-tendermint/src/main/java/io/hotmoka/node/tendermint/internal/TendermintStore.java
@@ -42,7 +42,7 @@
  * Tendermint, since it keeps such information inside its blocks.
  */
 @Immutable
-public class TendermintStore extends AbstractTrieBasedStore<TendermintStore, TendermintNodeImpl> {
+public class TendermintStore extends AbstractTrieBasedStore<TendermintStore> {
 
 	/**
 	 * The hasher used to merge the hashes of the many tries.