Mathematics

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yst 12:05
@XanderHenderson Well, I'm working on classifying ruled Weingarten surfaces in Thurston model geometries and this curve came up to be important in the case of the product space $\mathbb{H}^2\times \mathbb{R}$ just as the helix $(\cos t, \sin t, t)$ was important for $\mathbb{S}^2\times \mathbb{R}$. Part of me wants to call it "hyperbolic helix", but looking at the curve trace that seems really outrageous... Can't think of any other name

*Edit: the helix is also important for the Heisenberg group $\mathrm{Nil}_3$ space
yst 02:12
Hi, guys! Hope you all doing well. The curve $(\cos t, \sin t, t)$ is called a "helix". Does the "hyperbolic version" $(\cosh t, \sinh t, t)$ also have a nice name? If not, what name would you guys suggest?
Dec 7, 2024 13:37
@Thorgott Thanks
Dec 7, 2024 11:51
Hi, guys. Basic question on smooth manifolds: I have an ambient manifold and a submanifold. Consider then a function and vector field on the submanifold. I can extend them to the ambient. I want to apply the vector field on the function (at a certain point of the submanifold). This will give me a number on this point (a function on the submanifold). Using the extensions instead but restricted to that point (submanifold) gives me the same number (function)?
Nov 25, 2024 23:30
@ModularMindset Makes sense
Nov 25, 2024 23:01
So maybe I could also call them hyperbolic, parabolic and elliptic geodesics @leslietownes
Nov 25, 2024 23:00
And green ones (timelike), their projections look like circles entirely contained in the disk
Nov 25, 2024 23:00
I haven't proved but it seems like blue geodesics go to two points in the boundary (one above and other below the Poincaré disk). The red one (lightlike separating geodesic), seems to be asympotic to the boundary
Nov 25, 2024 22:58
And looking from above...
Nov 25, 2024 22:58
Nov 25, 2024 22:58
@ModularMindset This really looks like $\widetilde{SL(2,\mathbb{R})}$! Where did you get that image from?
Nov 25, 2024 22:52
(because, that's his disk in the figure, ofc)
Nov 25, 2024 22:51
Or something
Nov 25, 2024 22:51
I thought maybe Poincaré hated blue...
Nov 25, 2024 22:51
lol
Nov 25, 2024 22:50
@ModularMindset Why shouldn't be blue?
Nov 25, 2024 22:49
@copper.hat Maybe it is, I think you can check from another angles geogebra.org/classic/cb5hbbzw
Nov 25, 2024 22:45
Blue ones are the toocute geodesics @leslietownes
Nov 25, 2024 22:44
The geodesics in $\widetilde{SL(2,\mathbb{R})}$ I was talking about
Nov 25, 2024 22:44
Nov 25, 2024 22:43
Hi, guys
Nov 24, 2024 22:59
@BenSteffan What? Don't we rinse these things after wash?
Nov 24, 2024 22:51
I don't recommend it. Maybe black lotus tastes better
Nov 24, 2024 22:49
@Jakobian Only one gulp, but it was fast and huge
Nov 24, 2024 22:48
I forgot I left the bottle with detergent in it :P
Nov 24, 2024 22:47
Came back home after a jog, thirsty, and took a huge gulp from the first gatorade bottle I've seen, which seemed to have water in it...
Nov 24, 2024 22:46
@Jakobian I drank dishwashing detergent once (not so long ago)
Nov 24, 2024 17:57
I really liked @leslietownes suggestion of naming them "too cute", but maybe space/light/time like is a bit better
Nov 24, 2024 17:55
I just needed to give them some names...
Nov 24, 2024 17:55
hahahahaha
Nov 24, 2024 17:54
lol @BenSteffan Not yet, for me it's just $\widetilde{SL_2(\mathbb{R})}$ geometry, I don't care for any physical interpretation (for now)
Nov 24, 2024 17:51
$\alpha=\frac{\pi}{4}$ is the separating light-like cone direction...
Nov 24, 2024 17:50
@leslietownes About the angles: one should call them space/light/time-like geodesics. Their model justify this terminology
Nov 24, 2024 14:17
So, the cases I want to distinguish can be said in terms of $2\alpha$, using the names acute, obtuse and right angles
Nov 24, 2024 14:16
Well, if we look at $2\alpha$... It lies on $[0,\pi]$, with the separating case right in $\frac{\pi}{2}$...
Nov 24, 2024 14:13
supercute names
Nov 24, 2024 14:13
LOL
Nov 24, 2024 14:12
I hate it.
Nov 24, 2024 14:12
What about hoblique, roblique and voblique?
Nov 24, 2024 14:07
@SineoftheTime How should I call these angles?
Nov 24, 2024 14:03
There are also all the claims about Uranus
Nov 24, 2024 14:02
@leslietownes hahahahaah
Nov 24, 2024 14:02
core.ac.uk/download/pdf/14416005.pdf In here, they call these cases "$\mathbb{H}^2$-like", "separating light" and "fiber-like" directions, but I don't like them either lol
Nov 24, 2024 14:00
lol thanks
Nov 24, 2024 13:59
The space is $\widetilde{SL_2(\mathbb{R})}$
Nov 24, 2024 13:59
I don't know how to call them
Nov 24, 2024 13:59
The "$45^\circ$" geodesics will have a kind of asympotic behavior, those with a higher angle than that, but not vertical, will go "more" in the vertical direction and those with a lesser angle "more" in the basis direction...
Nov 24, 2024 13:57
And then, things in between...
Nov 24, 2024 13:57
We also have horizontal one (in the direction of the basis space)
Nov 24, 2024 13:57
Then, we have the fibers as vertical geodesics.