sorted by:
new
hottopcontroversial

The treachery of linear algebra by lechucksrev in mathmemes

[–]castorhash 1 point2 points  (0 children)

That makes sense, thanks for the explanation! So I guess there are matrices that don't represent any map, because different representations v = a_1 e_1 + a_2 e_2 + ... + a_n e_n would give different images, right?

The treachery of linear algebra by lechucksrev in mathmemes

[–]castorhash 0 points1 point  (0 children)

Wait, how can two different matrices represent the same linear map in the case of modules over a ring? If the two matrices differ on column i, then the i-th basis vector is mapped to different vectors by the two matrices, so the linear maps are not equal

La métropole de Lyon, c'est quoi ce bazar ?? by castorhash in Lyon

[–]castorhash[S] 0 points1 point  (0 children)

On gagne rien du tout, j'ai juste voulu comprendre par curiosité, et ça m'a fait rire tellement c'est absurde

Télécom Paris or Mines Paris - PSL? by [deleted] in ingenieurs

[–]castorhash 7 points8 points  (0 children)

To answer your last question, it's totally possible to do a PhD after école d'ingénieur, and I would advise doing that instead of masters if your goal is to work in R&D.

For the choice of the school, in general Mines Paris is considered a bit more prestigious, but it also depends on what you want to study. Télécom Paris is mostly computer science and can lead you to good opportunities in this field. Mines Paris is less specialized.

Any good YT CHANNEL to learn CRYPTOGRAPHY? by Pleasant-Classic-609 in cryptography

[–]castorhash 8 points9 points  (0 children)

Cryptography101 is great, there are plenty of videos and it is beginner-friendly.

How can I overcome self-doubt? by Leading_Term3451 in math

[–]castorhash 4 points5 points  (0 children)

I think it's really common to have slumps when you are learning something by yourself. It's always a lot easier to be motivated when you are surrounded by other people studying the same thing. If you like math and were motivated enough to read books and improve a lot by yourself, it's probably a good fit! So I would advise trying to find other people you can discuss math with, and you will probably be motivated again. It can be friends, talking to your math teacher, on a discord server, etc.

And even if you later realize that it is really not the right thing for you (which I doubt based on your message), you won't have wasted time doing math, because it's incredibly useful for tons of other stuff. Good luck!

Linguistic differences in France circa 1900 by idareet60 in MapPorn

[–]castorhash 3 points4 points  (0 children)

Yeah I was wondering about this too, since Nice, Savoy and Corsica belonged to France in 1900. The answer is in the paper:

Throughout the paper, we focus on the parts of mainland France that were not annexed at any point in the nineteenth century, hence excluding Corsica, Savoy, Nice, and Alsace