diff --git a/thys/Poincare_Disc/ROOT b/thys/Poincare_Disc/ROOT
--- a/thys/Poincare_Disc/ROOT
+++ b/thys/Poincare_Disc/ROOT
@@ -1,21 +1,21 @@
 chapter AFP
 
-session Poincare_Disc (AFP) = HOL +
+session Poincare_Disc (AFP) = Complex_Geometry +
   options [timeout = 1200]
   sessions
     "Complex_Geometry"
   theories
     Hyperbolic_Functions
     Tarski
     Poincare_Lines
     Poincare_Lines_Ideal_Points
     Poincare_Distance
     Poincare_Circles
     Poincare_Between
     Poincare_Lines_Axis_Intersections
     Poincare_Perpendicular
     Poincare
     Poincare_Tarski
   document_files
     "root.bib"
     "root.tex"