Zulip Chat Archive
Stream: mathlib4
Topic: Overloading dot notation
Steven Clontz (Jul 17 2024 at 19:24):
Working to port all SeparatedNhds
to use disjoint filters, I have theorems written like this:
theorem Disjoint.disjointOpenNhds {s t : Set X} (dis : Disjoint (𝓝ˢ s) (𝓝ˢ t)) :
∃ u v, IsOpen u ∧ s ⊆ u ∧ IsOpen v ∧ t ⊆ v ∧ Disjoint u v :=
sorry
theorem Disjoint.disjointOpenNhds' {x y : X} (dis : Disjoint (𝓝 x) (𝓝 y)) :
∃ u v, IsOpen u ∧ x ∈ u ∧ IsOpen v ∧ y ∈ v ∧ Disjoint u v :=
sorry
Which would provide a convenient way to obtain the "right" open neighborhoods by calling disSets.disjointOpennhds
where disSets : Disjoint (𝓝ˢ s) (𝓝ˢ t)
, and calling disPts.disjointOpennhds'
where disPts : Disjoint (𝓝 s) (𝓝 y)
.
My question: is there a way to make both methods be simply .disjointOpenNhds
?
Eric Wieser (Jul 17 2024 at 19:36):
I don't think so, but also the first one is about docs#nhdsSet not docs#nhds so should be named differently anyway
Steven Clontz (Jul 17 2024 at 20:35):
Sounds reasonable, perhaps
theorem Disjoint.disjointOpenNhdsSet {s t : Set X} (dis : Disjoint (𝓝ˢ s) (𝓝ˢ t)) :
∃ u v, IsOpen u ∧ s ⊆ u ∧ IsOpen v ∧ t ⊆ v ∧ Disjoint u v :=
sorry
theorem Disjoint.disjointOpenNhds {x y : X} (dis : Disjoint (𝓝 x) (𝓝 y)) :
∃ u v, IsOpen u ∧ x ∈ u ∧ IsOpen v ∧ y ∈ v ∧ Disjoint u v :=
sorry
and I guess (?)
theorem Disjoint.disjointOpenNhdNhdSet {x : X} {t : Set X} (dis : Disjoint (𝓝 x) (𝓝ˢ t)) :
∃ u v, IsOpen u ∧ x ∈ u ∧ IsOpen v ∧ t ⊆ v ∧ Disjoint u v :=
sorry
theorem Disjoint.disjointOpenNhdSetNhd {s : Set X} {y : X} (dis : Disjoint (𝓝ˢ s) (𝓝 y) ) :
∃ u v, IsOpen u ∧ s ⊆ u ∧ IsOpen v ∧ y ∈ v ∧ Disjoint u v :=
sorry
Eric Wieser (Jul 17 2024 at 22:08):
Note the naming convention for theorems is snake_case
Steven Clontz (Jul 18 2024 at 01:29):
then perhaps Disjoint.disjoint_open_nhdsSet
, Disjoint.disjoint_open_nhds
, Disjoint.disjoint_open_nhd_nhdSet
, and Disjoint.disjoint_open_nhdSet_nhd
Last updated: May 02 2025 at 03:31 UTC