Stream: Archive Mirror: Isabelle Users Mailing List

Topic: [isabelle] HOL-Word contains trivial lemmas


view this post on Zulip Email Gateway (Aug 22 2022 at 09:13):

From: Lars Hupel <hupel@in.tum.de>
It appears that there are two occurrences of "True" in HOL-Word:

lemma "True"

Auto solve_direct: The current goal can be solved directly with
HOL.TrueI: True
Word_Miscellaneous.z1pdiv2': True
Word_Miscellaneous.z1pmod2': True

The definitions of these lemmas are:

lemmas z1pmod2' = zero_le_one [THEN pos_zmod_mult_2, simplified]
lemmas z1pdiv2' = zero_le_one [THEN pos_zdiv_mult_2, simplified]

This is already the case for Isabelle2014.

I guess the header of the Word_Miscellaneous theory is even more spot on
than Florian intended :-)

header {* Miscellaneous lemmas, of at least doubtful value *}

Cheers
Lars

view this post on Zulip Email Gateway (Aug 22 2022 at 09:13):

From: Gerwin Klein <Gerwin.Klein@nicta.com.au>
Looks like the [simplified] does now more than it used to.

We should definitely remove these two.

Cheers,
Gerwin


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view this post on Zulip Email Gateway (Aug 22 2022 at 09:13):

From: Lars Hupel <hupel@in.tum.de>

We should definitely remove these two.

https://isabelle.in.tum.de/testboard/Isabelle/rev/243cee7c1e19

view this post on Zulip Email Gateway (Aug 22 2022 at 09:17):

From: Florian Haftmann <florian.haftmann@informatik.tu-muenchen.de>
This forward-transformation style with a volatile background context is
inherently brittle and should be avoided.

In the HOL-Word theories, there are indeed plenty opportunities for
renovation.

Florian
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Last updated: Mar 29 2024 at 04:18 UTC