diff --git a/alib2algo/src/arbology/exact/ExactPatternMatch.h b/alib2algo/src/arbology/exact/ExactPatternMatch.h
index 608f31a75621c25134a90017e64865b6ffaa9da9..6e00cc5223d763d5dd95d4253e1e0551a1cfbdbe 100644
--- a/alib2algo/src/arbology/exact/ExactPatternMatch.h
+++ b/alib2algo/src/arbology/exact/ExactPatternMatch.h
@@ -80,7 +80,7 @@ private:
 	static bool matchUnorderedHelper ( const ext::tree < common::ranked_symbol < SymbolType > > & subject, const ext::tree < common::ranked_symbol < SymbolType > > & pattern, const common::ranked_symbol < SymbolType > & subtreeVariable );
 
 	template < class SymbolType >
-	static void matchUnorderedInternal ( unsigned & index, ext::set < unsigned > & occ, const ext::tree < common::ranked_symbol < SymbolType > > & subject, const ext::tree < common::ranked_symbol < SymbolType > > & pattern, const common::ranked_symbol < SymbolType > & subtreeVariable );
+	static void matchUnorderedInternal ( unsigned & index, ext::set < unsigned > & occ, const ext::tree < SymbolType > & subject, const ext::tree < SymbolType > & pattern, const SymbolType & subtreeVariable );
 
 };
 
@@ -190,12 +190,12 @@ bool ExactPatternMatch::matchUnorderedHelper ( const ext::tree < common::ranked_
 }
 
 template < class SymbolType >
-void ExactPatternMatch::matchUnorderedInternal ( unsigned & index, ext::set < unsigned > & occ, const ext::tree < common::ranked_symbol < SymbolType > > & subject, const ext::tree < common::ranked_symbol < SymbolType > > & pattern, const common::ranked_symbol < SymbolType > & subtreeVariable ) {
+void ExactPatternMatch::matchUnorderedInternal ( unsigned & index, ext::set < unsigned > & occ, const ext::tree < SymbolType > & subject, const ext::tree < SymbolType > & pattern, const SymbolType & subtreeVariable ) {
 	if ( matchUnorderedHelper ( subject, pattern, subtreeVariable ) ) occ.insert ( index );
 
 	index++;
 
-	for ( const ext::tree < common::ranked_symbol < SymbolType > > & child : subject.getChildren ( ) )
+	for ( const ext::tree < SymbolType > & child : subject.getChildren ( ) )
 		matchUnorderedInternal ( index, occ, child, pattern, subtreeVariable );
 }