diff --git a/thys/Projective_Measurements/ROOT b/thys/Projective_Measurements/ROOT
--- a/thys/Projective_Measurements/ROOT
+++ b/thys/Projective_Measurements/ROOT
@@ -1,14 +1,14 @@
 chapter AFP
 
 session Projective_Measurements (AFP) = "HOL-Probability" +
   options [timeout = 600]
   sessions
-	Isabelle_Marries_Dirac
-	QHLProver
-	"HOL-Types_To_Sets"
+    Isabelle_Marries_Dirac
+    QHLProver
+    "HOL-Types_To_Sets"
   theories
     Linear_Algebra_Complements
-	Projective_Measurements
-	CHSH_Inequality
+    Projective_Measurements
+    CHSH_Inequality
   document_files
     "root.tex"