diff --git a/src/claim.c b/src/claim.c
index 3b509b5..af4c2af 100644
--- a/src/claim.c
+++ b/src/claim.c
@@ -15,8 +15,11 @@
 
 /*
  * Validity checks for claims
+ *
+ * Note that the first few operate on claims, and that the tests for e.g. the Arachne engine are seperate.
  */
 
+
 #ifdef OKIDEBUG
 int indac = 0;
 
@@ -440,3 +443,14 @@ check_claim_niagree (const System sys, const int i)
   termmapDelete (g);
   return result;
 }
+
+
+//! Check arachne agreement claim
+/**
+ * Per default, occurs in run 0, but for generality we have left the run parameter in.
+ *@returns 1 if the claim is true, 0 if it is not.
+ */
+int arachne_claim_agree (const System sys, const int claim_run, const int claim_index)
+{
+}
+
diff --git a/src/compiler.c b/src/compiler.c
index 93f4419..9832cdb 100644
--- a/src/compiler.c
+++ b/src/compiler.c
@@ -20,6 +20,19 @@
 static System sys;
 static Tac tac_root;
 
+/*
+ * Structure to store label information
+ */
+struct labelinfo
+{
+    Term label;
+    Term protocol;
+    Term sendrole;
+    Term readrole;
+};
+
+typedef struct labelinfo Labelinfo;
+
 /*
  * Declaration from system.c
  */
@@ -898,6 +911,8 @@ compute_role_variables (const System sys, Protocol p, Role r)
  * a mapping from all events to event/claim labels.
  * A second table is used to compute the precedence order, and 
  * Warshall's algorithm is used to compute the transitive closure.
+ * Then, for each claim, the in the preceding labels occurring roles are stored,
+ * which is useful later.
  *@returns For each claim in the claim list, a preceding label set is defined.
  */
 void
diff --git a/src/label.c b/src/label.c
new file mode 100644
index 0000000..8e4b3f6
--- /dev/null
+++ b/src/label.c
@@ -0,0 +1,25 @@
+/**
+ * Label info
+ */
+
+#include "memory.h"
+#include "term.h"
+#include "label.h"
+
+Labelinfo label_create (const Term label, const Term protocol)
+{
+  Labelinfo li;
+
+  li = (Labelinfo) memAlloc (sizeof (struct labelinfo));
+  li->label = label;
+  li->protocol = protocol;
+  li->sendrole = NULL;
+  li->readrole = NULL;
+  return li;
+}
+
+void label_destroy (Labelinfo linfo)
+{
+  memFree (linfo, sizeof (struct labelinfo));
+}
+
diff --git a/src/label.h b/src/label.h
new file mode 100644
index 0000000..71ed060
--- /dev/null
+++ b/src/label.h
@@ -0,0 +1,22 @@
+#ifndef LABEL
+#define LABEL
+
+#include "term.h"
+
+/*
+ * Structure to store label information
+ */
+struct labelinfo
+{
+    Term label;
+    Term protocol;
+    Term sendrole;
+    Term readrole;
+};
+
+typedef struct labelinfo* Labelinfo;
+
+Labelinfo label_create (const Term label, const Term protocol);
+void label_destroy (Labelinfo linfo);
+
+#endif
diff --git a/src/system.c b/src/system.c
index 381632e..d3a3966 100644
--- a/src/system.c
+++ b/src/system.c
@@ -97,6 +97,7 @@ systemInit ()
   sys->rolecount = 0;
   sys->roleeventmax = 0;
   sys->claimlist = NULL;
+  sys->labellist = NULL;
 
   /* matching CLP */
   sys->constraints = NULL;	// no initial constraints
diff --git a/src/system.h b/src/system.h
index 9e3c8ee..e9cacff 100644
--- a/src/system.h
+++ b/src/system.h
@@ -176,6 +176,7 @@ struct system
   int roleeventmax;		//!< Maximum number of events in a single role
   int lastChooseRun;		//!< Last run with a choose event
   Claimlist claimlist;		//!< List of claims in the system, with occurrence counts
+  List labellist;		//!< List of labelinfo stuff
 
   /* constructed trace pointers, static */
   Roledef *traceEvent;		//!< Trace roledefs: MaxRuns * maxRoledef