diff -r a697421eaa04 -r 598741d39d21 progs/display/thompson1.scala
--- a/progs/display/thompson1.scala	Fri Apr 28 11:01:25 2017 +0100
+++ b/progs/display/thompson1.scala	Sun May 07 00:20:58 2017 +0100
@@ -16,23 +16,23 @@
 }
 
 
-// some types abbreviations
+// a type abbreviation
 type NFAt = NFA[TState, Char]
 
 
-// NFA that does not accept any string
+// a NFA that does not accept any string
 def NFA_ZERO(): NFAt = {
   val Q = TState()
   NFA(Set(Q), { case _ => Set() }, Set())
 }
 
-// NFA that accepts the empty string
+// a NFA that accepts the empty string
 def NFA_ONE() : NFAt = {
   val Q = TState()
   NFA(Set(Q), { case _ => Set() }, Set(Q))
 }
 
-// NFA that accepts the string "c"
+// a NFA that accepts the string "c"
 def NFA_CHAR(c: Char) : NFAt = {
   val Q1 = TState()
   val Q2 = TState()