Stream: Archive Mirror: Isabelle Users Mailing List

Topic: [isabelle] proving monotonicity


view this post on Zulip Email Gateway (Aug 18 2022 at 09:40):

From: Christian Urban <urbanc@in.tum.de>
Hi Temesghen,

Temesghen Kahsai writes:

Hi all,

is there any difference in Isabelle\HOL the following two formulas:

1) \<forall>x \<in>A. P(x)
2) \<forall>x. x \<in> A --> P(x)

Regardless of whether A is an inductive set or not, there is no
difference with between the formulas in the sense that they
are interderivable:

lemma no_difference:
shows "(\<forall>x \<in>A. P(x)) = (\<forall>x. x \<in> A --> P(x))"
by auto

I even think (1) is defined in terms of (2). You can find out
by having a quick look at HOL.thy.

Hope this is helpful,
Christian

A is an inductive set.
I would like to use the first solution within a coinductive definition.
I don't get any error if I use the second solution, but if I use the
first one the coinductive definition fail to prove the monotonicity .

Any advice?

Thanks in advance for the collaboration.

Regards.

-T

view this post on Zulip Email Gateway (Aug 18 2022 at 09:42):

From: Christian Urban <urbanc@in.tum.de>

A is an inductive set.
I would like to use the first solution within a coinductive definition.
I don't get any error if I use the second solution, but if I use the
first one the coinductive definition fail to prove the monotonicity .

I forgot the most important information you need: you
can help Isabelle to prove monotonicity by providing
explicit theorems with the keyword "monos". See
Section 7.3.2 in the tutorial.

Christian


Last updated: Nov 21 2024 at 12:39 UTC