diff --git a/opencog/unify/Unify.cc b/opencog/unify/Unify.cc
index 2bfe4e38af..256a3a479a 100644
--- a/opencog/unify/Unify.cc
+++ b/opencog/unify/Unify.cc
@@ -493,15 +493,22 @@ Handle Unify::substitute_vardecl(const Handle& vardecl,
 	return createLink(std::move(oset), t);
 }
 
-
+// Return true iff the given handle is not in the given atomspace (if
+// any).
 static bool not_in_atomspace(const Handle& handle, const AtomSpace* atomspace)
 {
 	return nullptr != atomspace
 	   and nullptr == atomspace->get_atom(handle);
 }
 
-// Is a clause constant, relative to some atomspace?
-// Why would it matter whether or not it is in some atomspace?
+// Return true iff the given clause is constant and is not in the
+// given atomspace. A set of variables is provided to make the
+// distinction between variables and variable interpreted as constants
+// (they are constants is not in vars). Checking the present of the
+// clause in the atomspace matters because we don't want to trigger a
+// rule that will produce a term conditioned on the presence of a
+// clause that was actually not in the atomspace (that would have been
+// turned into a constant due to partial instantiation of a rule).
 static bool not_constant(const HandleSet& vars,
                          const Handle& clause,
                          const AtomSpace* as)
diff --git a/opencog/ure/backwardchainer/BIT.cc b/opencog/ure/backwardchainer/BIT.cc
index 604856dd0f..b6081f82bc 100644
--- a/opencog/ure/backwardchainer/BIT.cc
+++ b/opencog/ure/backwardchainer/BIT.cc
@@ -38,7 +38,7 @@
 #include <opencog/util/algorithm.h>
 #include <opencog/atoms/core/FindUtils.h>
 #include <opencog/atoms/core/TypeUtils.h>
-#include <opencog/atoms/execution/LibraryManager.h>
+#include <opencog/atoms/grounded/LibraryManager.h>
 #include <opencog/atoms/pattern/PatternUtils.h>
 
 #include "BIT.h"
diff --git a/opencog/ure/backwardchainer/ControlPolicy.cc b/opencog/ure/backwardchainer/ControlPolicy.cc
index d0414dd44a..ef4f348854 100644
--- a/opencog/ure/backwardchainer/ControlPolicy.cc
+++ b/opencog/ure/backwardchainer/ControlPolicy.cc
@@ -26,7 +26,7 @@
 #include <opencog/util/random.h>
 #include <opencog/util/algorithm.h>
 #include <opencog/unify/Unify.h>
-#include <opencog/atoms/execution/MapLink.h>
+#include <opencog/atoms/core/MapLink.h>
 
 #include "../MixtureModel.h"
 #include "../ActionSelection.h"
diff --git a/tests/ure/backwardchainer/BITUTest.cxxtest b/tests/ure/backwardchainer/BITUTest.cxxtest
index 8c7f4a09f5..8bdcc66cd7 100644
--- a/tests/ure/backwardchainer/BITUTest.cxxtest
+++ b/tests/ure/backwardchainer/BITUTest.cxxtest
@@ -168,19 +168,6 @@ void BITUTest::test_expand_1()
 		             "  (VariableSet"
 		             "  )"
 		             "  (AndLink"
-		             "    (PresentLink"
-		             "      (TypedVariableLink"
-		             "        (VariableNode \"$X\")"
-		             "        (TypeNode \"ConceptNode\")"
-		             "      )"
-		             "      (EvaluationLink"
-		             "        (PredicateNode \"contain\")"
-		             "        (ListLink"
-		             "          (ConceptNode \"treatment-1\")"
-		             "          (ConceptNode \"compound-A\")"
-		             "        )"
-		             "      )"
-		             "    )"
 		             "    (NotLink"
 		             "      (IdenticalLink"
 		             "        (LambdaLink"
diff --git a/tests/ure/backwardchainer/GradientUTest.cxxtest b/tests/ure/backwardchainer/GradientUTest.cxxtest
index 62564ca365..337bf130a3 100644
--- a/tests/ure/backwardchainer/GradientUTest.cxxtest
+++ b/tests/ure/backwardchainer/GradientUTest.cxxtest
@@ -24,7 +24,7 @@
 #include <opencog/util/mt19937ar.h>
 
 #include <opencog/atomspace/AtomSpace.h>
-#include <opencog/atoms/execution/LibraryManager.h>
+#include <opencog/atoms/grounded/LibraryManager.h>
 #include <opencog/atoms/truthvalue/SimpleTruthValue.h>
 #include <opencog/ure/backwardchainer/BackwardChainer.h>
 #include <opencog/ure/URELogger.h>