Zulip Chat Archive
Stream: general
Topic: galois correspondences
Johan Commelin (Nov 17 2018 at 06:29):
Do we already have the Galois correspondence for set.map
and set.comap
(aka, range
and preimage
)?
Is there machinery to glue Galois correspondences together? E.g. I would like to get a Galois correspondence for opens.map
and opens.comap
more or less for free.
Johannes Hölzl (Nov 17 2018 at 09:01):
its between set.image
and set.preimage
(and there is one between preimage
and kern_image f s := {y | ∀x, f x = y → x ∈ s}
)
Johannes Hölzl (Nov 17 2018 at 09:01):
its in data.set.lattice
Johan Commelin (Nov 17 2018 at 09:02):
Thanks
Last updated: Dec 20 2023 at 11:08 UTC