diff --git a/grammars/prelude/PredefAbs.gf b/grammars/prelude/PredefAbs.gf
new file mode 100644
index 000000000..2779bcd58
--- /dev/null
+++ b/grammars/prelude/PredefAbs.gf
@@ -0,0 +1,4 @@
+abstract PredefAbs = {
+  cat Int ; String ;
+} ;
+