Observations

For Turing Machine, that is.

<pre>

val EUC: Machine = Machine("Euclid",
  "start",
  "start" -> "start 0R / atFirst 1L",
  "atFirst" -> "beforeFirst 1R / atFirst 1L",
  "beforeFirst" -> "done 0R / skipFirst 0R",
  "skipFirst" -> "separator 0R / skipFirst 1R",
  "separator" -> "separator 0R / atSecond 0R",
  "atSecond" -> "doneSubtraction 0L / backToFirst 1L",
  "backToFirst" -> "backToFirst 0L / atFirst 1L",
  "doneSubtraction" -> "doneSubtraction 0L / skipSecond 1L",
  "skipSecond" -> "beforeSecond 0L / skipSecond 1L",
  "beforeSecond" -> "beforeFirst 0R / atFirst 1L",
  "done" -> "done 0S / done 1R"
)

</pre> 

 

So I build an exponential set, AB, which is a Set of Maps; but the thing is, either A or B can be infinite, so the map entryset can be infinite, so I cannot compare two such exponentials, even check that a specific map belongs to such a set, since AbstractSet implementation of equals() first checks if the sizes are the same... but the size is undefined. I do not mind if it just hangs listing the elements, trying to find one that does not belong; for this I may have a patience argument (halting it arbitrarily).