diff --git a/kiwi/kiwi/solver.h b/kiwi/kiwi/solver.h
index 8ff2dbb..3e510f9 100644
--- a/kiwi/kiwi/solver.h
+++ b/kiwi/kiwi/solver.h
@@ -145,7 +145,7 @@ public:
 	/* Dump a representation of the solver internals to stdout.
 
 	*/
-	void dump()
+	void dump() const
 	{
 		debug::dump( m_impl );
 	}
@@ -153,7 +153,7 @@ public:
 	/* Dump a representation of the solver internals to a stream.
 
 	*/
-	void dump( std::ostream& out )
+	void dump( std::ostream& out ) const
 	{
 		debug::dump( m_impl, out );
 	}
@@ -161,7 +161,7 @@ public:
 	/* Dump a representation of the solver internals to a string.
 
 	*/
-	std::string dumps()
+	std::string dumps() const
 	{
 		return debug::dumps( m_impl );
 	}
diff --git a/kiwi/kiwi/variable.h b/kiwi/kiwi/variable.h
index 98d7499..ee0939e 100644
--- a/kiwi/kiwi/variable.h
+++ b/kiwi/kiwi/variable.h
@@ -72,7 +72,7 @@ public:
     }
 
     // operator== is used for symbolics
-    bool equals(const Variable &other)
+    bool equals(const Variable &other) const
     {
         return m_data == other.m_data;
     }