Nico A

general recent conversations

$Mathematics$ Mathematics

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Nico A

Feb 26, 2021 04:41

And even though the domain will be a strict subset of X we still consider that a function X ->X?

Nico A

Feb 26, 2021 04:40

We can literally take f^-1 for each element that’s mapped to right?

Nico A

Feb 26, 2021 04:39

Yup I just got it thank you

Nico A

Feb 26, 2021 04:31

rather than a group

Nico A

Feb 26, 2021 04:31

oh wait X being a set doesn’t change anything right?

Nico A

Feb 26, 2021 04:22

for some reason our homework is to prove that we can so i was a bit confused lol

Nico A

Feb 26, 2021 04:21

okay so we can't, that's what i thought

Nico A

Feb 26, 2021 04:16

@Thorgott so the inverse would be g(x)=x/2 but thats not a map from Z->Z, right?

Nico A

Feb 26, 2021 04:15

i think the domains are just confusing me because neccesarily we have elements in the codomain of f that aren't mapped to, so how could g o f be the identity?

Nico A

Feb 26, 2021 04:13

Hey quick sanity-check group theory q: if we have f: X->X is injective but not surjective, can we show there exists a map g : X->X such that g(f(x)) is the identity?

Nico A

Feb 15, 2021 10:13

I'm having trouble thinking of what the vectors (and other scalars) would be in such a space, such that scalar addition and multiplication by a vector satisfy the normal axioms

Nico A

Feb 15, 2021 10:12

and i'm wondering if we can construct a vector space where the complex numbers (taken as a field, set, topological space, whatever you want) sort of "naturally appear" as one of the scalars.

Nico A

Feb 15, 2021 10:12

i have a crazy, pretty non-mathematical question - but I was talking with some friends about how the scalars in a vector space don't necessarily need to be reals or complex numbers, the conversation devolved

Nico A

Feb 3, 2021 00:05

Also the Yang paper is only for Riemannian manifolds, do you know if there's an answer / result for psuedo-Riemannian manifolds?

Nico A

Feb 3, 2021 00:01

But thank you that makes sense!

Nico A

Feb 3, 2021 00:01

Yeah it's on sci hub

Nico A

Feb 2, 2021 23:04

It certainly might, i'm just trying teach myself rn

Nico A

Feb 2, 2021 23:02

@TedShifrin ?

Nico A

Feb 2, 2021 22:59

Hey quick diff geo question - is there a name for the class of manifolds such that you could define the surface in terms of a parametrization S where all the partial derivatives of S with respect to each parameter at any point produces a set of orthogonal vectors? Is this just all differentiable manifolds?

TreFox

May 31, 2018 21:13

Dang it. Guess I'll have to, thanks.

TreFox

May 31, 2018 21:12

Ok I'm scared to ask this on main because it's probably incredibly stupid, but I'm currently modeling a problem where a guy is at height $h$ and has to get over a wall of height $1$, is there any way to create a function saying how far he has to go to get over the wall without using a piecewise function? Because if he's above $1$ the function should return $0$, otherwise just $1-h$.

$Mathematics$ Math Mods' Office

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Nico A

Oct 9, 2020 03:31

Hey, are there any mods online that could help me out quickly in a private room?

$Mathematics$ Discussion on question by Sarah Griff…

Imported from a comment discussion on math.stackexchange.com/q...

Nico A

Sep 24, 2020 17:44

If you’re familiar with tensor categories, arxiv.org/pdf/1612.02762.pdf is a great example of color making some difficult computation much more intuitive. I’m not sure if there are similar tools in other fields, though - I’ve never seen anything quite like it.

Nico A

Sep 24, 2020 17:44

@rschwieb Similar questions about mathematical typesetting tools and representing mathematics visually have been well-received here (math.stackexchange.com/questions/57763/…, math.stackexchange.com/questions/733754/…), what makes this one different?

Ten fold

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TreFox

Oct 15, 2019 21:05

Can anyone do a sanity-check for me rq? If a distribution gives a certain probability p(x) for each pixel x in an image, the probability of generating the whole image is the product of p(x) over every pixel in the image?

Wolfram Mathematica

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TreFox

Jul 7, 2019 18:11

@CarlLange I was too. I ended up going with a CatenateLayer followed by a ReshapeLayer, which is a little ugly but works fine

TreFox

Jul 7, 2019 15:26

I'm making a neural network - at one step, there are 5 10-long vectors. How do I just join them together to a 5x10 vector? CatentateLayer makes them a 50 long vector

TreFox

Jul 1, 2019 19:40

@CATrevillian Newest. Desktop 12

TreFox

Jul 1, 2019 18:48

But the problem still doesn't seem to be fixed

TreFox

Jul 1, 2019 18:48

Nevermind, my question was a dupe of this: mathematica.stackexchange.com/questions/145115/…

TreFox

Jul 1, 2019 18:20

Q: Calling NetPortGradient changes the value of the neural network

I'm using Wolfram Desktop 12. Let's load a simple neural net model and an image to test it on: imageId = NetModel["Wolfram ImageIdentify Net V1"] image=ExampleData[{"TestImage", "Apples"}] Now, when I run imageId[image, "TopProbabilities"] I get: {Red Delicious -> 0.959278} Now, let's get t...

TreFox

Jul 1, 2019 18:20

Is anyone else getting this weird behavior?

TreFox

Jun 29, 2019 13:11

Is there a neural net layer just to take the maximum element of an array?

TreFox

Jun 23, 2019 23:01

Still new to this framework

TreFox

Jun 23, 2019 23:01

Maybe I'm being an idiot here

TreFox

Jun 23, 2019 23:01

I'm trying to make a neural net that takes a 16x100x100 matrix and splits it into each 100x100 part, puts each through a dense layer, and then puts them them together once again to form a 16x10x10 matrix. Is there any easier way than sending the input to 16 PartLayers and then each PartLayer to a LinearLayer?

TreFox

Jun 23, 2019 17:07

Perfect! Thank you

TreFox

Jun 23, 2019 16:26

Seems like solution would be too simple to warrant a question but for some reason I can't find a simple way to take a list that includes some rules and extract a certain rule. For example take {"a","b","c"->"test"} and get the value of the key "c"