Stream: Archive Mirror: Isabelle Users Mailing List

Topic: [isabelle] About mem and set


view this post on Zulip Email Gateway (Aug 18 2022 at 10:42):

From: Cristiano Longo <cristiano.longo@tvblob.com>
I can prove the following lemma

"x \<in> {} = x mem []"

but, simplyfing this one

"x mem [] = x \<in> {}"

it results as False.

thanks in advance,
Cristiano Longo

view this post on Zulip Email Gateway (Aug 18 2022 at 10:43):

From: Amine Chaieb <chaieb@in.tum.de>
This is the same behaviour as your last email. If you want the goal to
be parsed as an If and only if, the bracket it, otherwise use the <-->
symbol, it is = on bool with the usual prioities.

Of course x mem x is not a member of the empty set.
Amine.

Cristiano Longo wrote:


Last updated: Nov 21 2024 at 12:39 UTC