diff -r 0aa54181d7c9 -r e0d05326a79e src/Tools/isac/ROOT
--- a/src/Tools/isac/ROOT	Wed Nov 04 09:59:30 2020 +0100
+++ b/src/Tools/isac/ROOT	Wed Nov 11 17:27:11 2020 +0100
@@ -12,7 +12,7 @@
 *)
 
 (* run "./bin/isabelle build -v -b Interpret" *)
-session Interpret in Interpret = HOL +
+session Interpret in Interpret = "HOL-SPARK" +
   description "
     Session covering code required for ~~/src/Tools/isac/Doc.
   "
@@ -30,7 +30,7 @@
     "Interpret"
 
 (* run "./bin/isabelle build -v -b Isac"  *)
-session Isac = Interpret +
+session Isac = Interpret + 
   description "
     Isac core, prototype of a math-engine and knowledge 
     for a TP-based educational mathematics assistant.