I have investigated the possibility of replacing the existing complete_distrib_lattice with the stronger version.

Here are the problems:

1. The new class needs Hilbert choice in few places: proving the dual
of the distributivity property, proving the set and fun instantiations,
and proving that complete_linearord is subclass of the new class. I
think that the Hilbert choice cannot be avoided, as for example
Wikipedia page states that no nontrivial instance of this could exists
without the axiom of choice.

2. Hilbert_Choice comes very late in the library, and depends on the
Complete_Lattice.thy

One possible solution:

Add the new class in Complete_Lattice.thy, replacing the existing class

Prove the instantiations and the complete_linearord subclass later
in Hilbert_Choice.

Another possibility is to move everything related to complete
distributive lattice in a new theory that imports Hilbert_Choice,
but I don't know if the current distributivity properties are used
before Hilbert_Choice.

On the other hand, it seems inconvenient to have the Hilbert Choice
to depend on so many other theories.

Viorel

On 8/24/2017 6:40 PM, Florian Haftmann wrote:
As far as I remember, I introduced the complete_distrib_lattice class
after realizing the a complete lattice whose binary operations are
distributive is not necessarily a distributive complete lattice.  Hence
the specification of that type class has been contrieved without
consulting literature.

Hence that change should be fine if someone is willing to undertake it
before the RC stabilization phase.

Cheers,
        Florian

Am 24.08.2017 um 00:42 schrieb Lawrence Paulson:
Sounds good to me. Can anybody think of an objection?
Larry

On 23 Aug 2017, at 15:17, Viorel Preoteasa <viorel.preote...@aalto.fi
<mailto:viorel.preote...@aalto.fi>> wrote:

Hello,

I am not sure if this is the right place to post this message, but it is
related to  the upcoming release as I am prosing adding something
to the Isabelle library.

While working with complete distributive lattices, I noticed that
the Isabelle class complete_distrib_lattice is weaker compared to
what it seems to be regarded as a complete distributive lattice.

As I needed the more general concept, I have developed it,
and if Isabelle community finds it useful to be in the library,
then I could provide the proofs or integrate it myself in the
Complete_Lattice.thy

The only axiom needed for complete distributive lattices is:

Inf_Sup_le: "Inf (Sup ` A) ≤ Sup (Inf ` {f ` A | f . (∀ Y ∈ A . f Y ∈
Y)})"

and from this, the equality and its dual can be proved, as well as
the existing axioms of complete_distrib_lattice and the instantiation
to bool, set and fun.

Best regards,

Viorel


On 2017-08-21 21:24, Makarius wrote:
Dear Isabelle contributors,

we are now definitely heading towards the Isabelle2017 release.

The first official release candidate Isabelle2017-RC1 is anticipated for
2/3-Sep-2017, that is a bit less than 2 weeks from now.

That is also the deadline for any significant additions.


I have already updated the important files NEWS, CONTRIBUTORS, ANNOUNCE
in Isabelle/5c0a3f63057d, but it seems that many potential entries are
still missing.

Please provide entries in NEWS and CONTRIBUTORS for all relevant things
you have done since the last release.


Makarius
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