diff --git a/stdlib/src/main/resources/CSV.vdmpp b/stdlib/src/main/resources/CSV.vdmpp
index 356d06fca..37146d94b 100644
--- a/stdlib/src/main/resources/CSV.vdmpp
+++ b/stdlib/src/main/resources/CSV.vdmpp
@@ -1,3 +1,4 @@
+-- @NoPOG - do not generate obligations for this class
 class CSV
 
 --  Overture STANDARD LIBRARY: INPUT/OUTPUT
diff --git a/stdlib/src/main/resources/CSV.vdmrt b/stdlib/src/main/resources/CSV.vdmrt
index 356d06fca..37146d94b 100644
--- a/stdlib/src/main/resources/CSV.vdmrt
+++ b/stdlib/src/main/resources/CSV.vdmrt
@@ -1,3 +1,4 @@
+-- @NoPOG - do not generate obligations for this class
 class CSV
 
 --  Overture STANDARD LIBRARY: INPUT/OUTPUT
diff --git a/stdlib/src/main/resources/CSV.vdmsl b/stdlib/src/main/resources/CSV.vdmsl
index 071004670..bcabb174c 100644
--- a/stdlib/src/main/resources/CSV.vdmsl
+++ b/stdlib/src/main/resources/CSV.vdmsl
@@ -1,3 +1,4 @@
+-- @NoPOG - do not generate obligations for this module
 module CSV
 -- 	Overture STANDARD LIBRARY: INPUT/OUTPUT
 --      --------------------------------------------
diff --git a/stdlib/src/main/resources/IO.vdmpp b/stdlib/src/main/resources/IO.vdmpp
index 1c1446225..6a7fab1d7 100644
--- a/stdlib/src/main/resources/IO.vdmpp
+++ b/stdlib/src/main/resources/IO.vdmpp
@@ -1,3 +1,4 @@
+-- @NoPOG - do not generate obligations for this class
 class IO
 
 -- 	VDMTools STANDARD LIBRARY: INPUT/OUTPUT
diff --git a/stdlib/src/main/resources/IO.vdmrt b/stdlib/src/main/resources/IO.vdmrt
index 1c1446225..6a7fab1d7 100644
--- a/stdlib/src/main/resources/IO.vdmrt
+++ b/stdlib/src/main/resources/IO.vdmrt
@@ -1,3 +1,4 @@
+-- @NoPOG - do not generate obligations for this class
 class IO
 
 -- 	VDMTools STANDARD LIBRARY: INPUT/OUTPUT
diff --git a/stdlib/src/main/resources/IO.vdmsl b/stdlib/src/main/resources/IO.vdmsl
index 15f89b022..0eb400e65 100644
--- a/stdlib/src/main/resources/IO.vdmsl
+++ b/stdlib/src/main/resources/IO.vdmsl
@@ -1,3 +1,4 @@
+-- @NoPOG - do not generate obligations for this module
 module IO
 exports all
 definitions
diff --git a/stdlib/src/main/resources/MATH.vdmpp b/stdlib/src/main/resources/MATH.vdmpp
index 11287937c..97a4c4b71 100644
--- a/stdlib/src/main/resources/MATH.vdmpp
+++ b/stdlib/src/main/resources/MATH.vdmpp
@@ -1,3 +1,4 @@
+-- @NoPOG - do not generate obligations for this class
 class MATH
 
 -- 	VDMTools STANDARD LIBRARY: MATH
diff --git a/stdlib/src/main/resources/MATH.vdmrt b/stdlib/src/main/resources/MATH.vdmrt
index 11287937c..97a4c4b71 100644
--- a/stdlib/src/main/resources/MATH.vdmrt
+++ b/stdlib/src/main/resources/MATH.vdmrt
@@ -1,3 +1,4 @@
+-- @NoPOG - do not generate obligations for this class
 class MATH
 
 -- 	VDMTools STANDARD LIBRARY: MATH
diff --git a/stdlib/src/main/resources/MATH.vdmsl b/stdlib/src/main/resources/MATH.vdmsl
index dd891f51d..2dbc88523 100644
--- a/stdlib/src/main/resources/MATH.vdmsl
+++ b/stdlib/src/main/resources/MATH.vdmsl
@@ -1,3 +1,4 @@
+-- @NoPOG - do not generate obligations for this module
 module MATH
 exports all
 definitions
@@ -56,7 +57,7 @@ definitions
     sqrt:real -> real
     sqrt(a) ==
     is not yet specified
-    ;--pre a >= 0;
+    pre a >= 0;
 
     pi_f:() +> real
     pi_f () ==
diff --git a/stdlib/src/main/resources/VDMUtil.vdmpp b/stdlib/src/main/resources/VDMUtil.vdmpp
index b53ccc8f3..cf5f208be 100644
--- a/stdlib/src/main/resources/VDMUtil.vdmpp
+++ b/stdlib/src/main/resources/VDMUtil.vdmpp
@@ -1,3 +1,4 @@
+-- @NoPOG - do not generate obligations for this class
 class VDMUtil
 
 -- 	VDMTools STANDARD LIBRARY: MiscUtils
diff --git a/stdlib/src/main/resources/VDMUtil.vdmrt b/stdlib/src/main/resources/VDMUtil.vdmrt
index b53ccc8f3..cf5f208be 100644
--- a/stdlib/src/main/resources/VDMUtil.vdmrt
+++ b/stdlib/src/main/resources/VDMUtil.vdmrt
@@ -1,3 +1,4 @@
+-- @NoPOG - do not generate obligations for this class
 class VDMUtil
 
 -- 	VDMTools STANDARD LIBRARY: MiscUtils
diff --git a/stdlib/src/main/resources/VDMUtil.vdmsl b/stdlib/src/main/resources/VDMUtil.vdmsl
index dd2c69d93..e2bf1e8fe 100644
--- a/stdlib/src/main/resources/VDMUtil.vdmsl
+++ b/stdlib/src/main/resources/VDMUtil.vdmsl
@@ -1,3 +1,4 @@
+-- @NoPOG - do not generate obligations for this module
 module VDMUtil
 
 -- 	VDMTools STANDARD LIBRARY: MiscUtils