diff -r df9e966ecb6d -r dc0cdfc5fc66 Spiral.scala
--- a/Spiral.scala	Wed Feb 05 12:41:30 2020 +0000
+++ b/Spiral.scala	Wed Feb 05 14:50:57 2020 +0000
@@ -562,7 +562,7 @@
     val r = ("ab" | (  (("a")%) | "aa")  )
     //val r = ("a"|"b")~("a")
     val s = "aa"
-    for(i <- 0 to s.length-1){
+    for(i <- 1 to s.length-1){
       val ss = s.slice(0, i+1)
       val nangao = bders_simp_rf(ss.toList, internalise(r))
       val easy = (bders(ss.toList, internalise(r)))