muller's spec made even simpler

examples/programs/muller.mlw

@@ -12,13 +12,13 @@ module Muller
   let compact (a : array int) =
     let count = ref 0 in
     for i = 0 to length a - 1 do 
-      invariant { 0 <= count <= i and count = num_of a 0 i }
+      invariant { 0 <= count = num_of a 0 i <= i}
       if a[i] <> 0 then incr count
     done;
     let u = make !count 0 in
     count := 0;
     for i = 0 to length a - 1 do
-      invariant { 0 <= count <= i and count = num_of a 0 i and 
+      invariant { 0 <= count = num_of a 0 i <= i and 
                   length u = num_of a 0 (length a) }
       if a[i] <> 0 then begin u[!count <- a[i]]; incr count end
     done