added an intro lemma for freshness of products; set up
the simplifier so that it can deal with the compact and
long notation for freshness constraints (FIXME: it should
also be able to deal with the special case of freshness
of atoms)
structure ROOT =
struct
structure Codegen =
struct
val arbitrary_option : 'a option = NONE;
fun dummy_option [] = arbitrary_option
| dummy_option (x :: xs) = SOME x;
end; (*struct Codegen*)
end; (*struct ROOT*)