[isabelle-dev] NEWS

[Florian Haftmann]

>> 'set' is now a proper type constructor.  Definitions mem_def and
>> Collect_def have disappeared.  INCOMPATIBILITY, rephrase sets S used as
>> predicates by `%x. x : S` and predicates P used as sets by `{x. P x}`.
>> For typical proofs, it is often sufficent to prune any tinkering with
>> former theorems mem_def and Collect_def.
> 
> The NEWS entry looks a bit too optimistic.  The majority of users after
> Isabelle2008 will have to change their theories, and need some more
> explicit instructions how to do it sucessfully (e.g. port forwards by
> eliminating mem_def/Collect_def before making the actual jump into the
> new version).

Good question how such explicit instructions could look like.
Eliminating mem_def/Collect_def in a first pass is usually not feasible,
because the set/pred-ignorant versions of Isabelle tended to move back
and forth between both worlds by their automation setup.  The migration
strategy had always been to adjust terms to respect the set/pred
distinction, and then adjust the proofs accordingly.  No trick behind it.

	Florian

-- 

Home:
http://www.in.tum.de/~haftmann

PGP available:
http://home.informatik.tu-muenchen.de/haftmann/pgp/florian_haftmann_at_informatik_tu_muenchen_de

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 262 bytes
Desc: OpenPGP digital signature
URL: <https://mailman46.in.tum.de/pipermail/isabelle-dev/attachments/20120104/63c9cec7/attachment.sig>