diff --git a/sledge/src/fol/context.ml b/sledge/src/fol/context.ml
index 2ad3a0798..f10b047bc 100644
--- a/sledge/src/fol/context.ml
+++ b/sledge/src/fol/context.ml
@@ -199,7 +199,8 @@ end = struct
       in
       if s' != s then partition_valid_ t' ks' s' else (t', ks', s')
     in
-    partition_valid_ empty xs s
+    if Var.Set.is_empty xs then (s, Var.Set.empty, empty)
+    else partition_valid_ empty xs s
 
   (* direct representation manipulation *)