"Steve Holden" <sholden at holdenweb.com> wrote ...
> When you refer to an "upgrading function" I suspect you mean a coercion?
> There's no need for a coercion, since for any Strange instance s, s+x == s
> for any x (and, indeed, s+x is x as well)\
That last should, of course, have read
(and, indeed, s+x is s as well)