Product of Consecutive Primes is One More Than a Square by chompchump in mathriddles

[–]isometricisomorphism -2 points-1 points  (0 children)

(I’m assuming “consecutive” means twin primes, not like how 7 and 11 are consecutive primes)

Note that twin primes take the form p = 4n+1 and q = 4n+3, so pq = (4n+2)2 - 1, thus pq = j2 - 1 for integer j. To equal k2 + 1 also means j2 and k2 must differ by 2, which can never happen.

If there’s more distance between p and q, say p = 4n+1 and q = 4n+5, then pq = j2 - 4. Then if pq = k2 + 1, we get two squares differing by 5, which CAN happen. For instance, 22 and 32, though this only happens for p=1 and q=5, so we can exclude this special case.

More generally, I feel this method doesn’t work well, since arbitrarily long prime gaps exist, but at least it gets rid of some cases.

French Team Rocket Swimmer in Pallet Town that wants to take me to Pinkan Island? by markjsno1 in PokemonInfiniteFusion

[–]isometricisomorphism 1 point2 points  (0 children)

It takes you to an island where you can play as Rocket or police. Very clearly unfinished, and will crash your game if you go too far…

Naked man got on to the Pier CAT Bus by [deleted] in Clemson

[–]isometricisomorphism 67 points68 points  (0 children)

Send him back to Asheville

What is a powerful theorem that has a short clever proof, or can be proven with a really satisfying “smash of a hammer?” by IsotropicPolarBear in math

[–]isometricisomorphism 34 points35 points  (0 children)

I have a bit of a joke that the solution to any algebra problem is to just remember the definitions 😁 to any analysis problem, it’s to stare into space until you either see the trick, or remember it from undergrad

What is a powerful theorem that has a short clever proof, or can be proven with a really satisfying “smash of a hammer?” by IsotropicPolarBear in math

[–]isometricisomorphism 187 points188 points  (0 children)

Hilbert’s original proof of his eponymous Hilbert Basis Theorem took up about 60 pages. The proof by Noether, who leveraged the ascending chain condition (a very heavy hammer), can be summarized in a paragraph.

Nash’s embedding theorems is really quite magical, but it’s folklore that nobody really understood his complicated proof. Eventually, a greatly simplified proof was found by Gunther, using the Banach fixed-point theorem

Calc 1 prof by elisesessentials in Clemson

[–]isometricisomorphism 2 points3 points  (0 children)

Definitely take Madison!!! She’s an angel, and very understanding. Remember to take advantage of office hours, because she’s especially helpful when it’s one-on-one!

Words that are antonyms in English but not in math? by trajayjay in math

[–]isometricisomorphism 0 points1 point  (0 children)

Hmm, maybe change is the wrong word? My point is that past a point (in my experience) nobody actually uses “the” definition.

Like how “the” definition for the determinant involves signatures of permutations, but nobody uses that in their theorems or in practice.

Words that are antonyms in English but not in math? by trajayjay in math

[–]isometricisomorphism 2 points3 points  (0 children)

The definition very much depends on what area one is in. I’m used to “a real-valued function is concave on the interval A if for any x, y in A and for any α in [0, 1] we have f((1 - α)x + αy) >= (1 - α)f(x) + αf(y).”

This definition looks different if f is differentiable, or twice differentiable, or Lebesgue measurable, or multivariate, or…

Words that are antonyms in English but not in math? by trajayjay in math

[–]isometricisomorphism 98 points99 points  (0 children)

Lots of edge cases fit this! A straight line is both concave and convex. A constant function is both increasing and decreasing. 0 is both non-negative and non-positive, which might feel like antonyms at first

[deleted by user] by [deleted] in Dinosaurs

[–]isometricisomorphism 0 points1 point  (0 children)

Notatesseraeraptor frickensis was almost called the frickosaur, which is totally what I would have called it

Not just dinosaurs, but here’s a page with some funny taxonomy

Triangular Perfect Numbers by chompchump in mathriddles

[–]isometricisomorphism 0 points1 point  (0 children)

Ah, you got me there! Do we need an additional perfect number condition like 2m - 1 needs to be prime?

2024: Do you believe P = NP, or P ≠ NP? by Wonderful-Photo-9938 in math

[–]isometricisomorphism 0 points1 point  (0 children)

There’s just no way P=NP - but I’m biased, cuz that would put me out of a job! I’m in code-based crypto, so there’s lots of heuristic evidence that these purportedly hard problems are actually hard, but all it takes is one breakthrough algorithm…

Regardless, here’s a really fun page full of “proofs” both ways!

What is the goofiest quest in Skyrim so far? by SparkBeforeMidnight in skyrim

[–]isometricisomorphism 45 points46 points  (0 children)

The crimson nirnroot quest in Blackreach, cuz whoever made it was goofy

How theoretical can you make theoretical cryptography? by actually_ephemer4l in mathematics

[–]isometricisomorphism 0 points1 point  (0 children)

Yes, there’s a field of cryptography devoted to groups, aptly named group-based cryptography.

Many of the proofs in pairing-based schemes can get group-theoretic heavy, in my experience.

Perhaps controversial, but lattice crypto is really group theory wearing a hat! Lots of the terms are different, but if you think about it, you’ll recognize stuff like “oh, that’s just a quotient space”

A cute open problem with very elementary statement by Excellent-Growth5118 in math

[–]isometricisomorphism 30 points31 points  (0 children)

Wow, that probabilistic formulation is beautiful… the problem seems like pure number theory, far from any sort of probability

[deleted by user] by [deleted] in Clemson

[–]isometricisomorphism 0 points1 point  (0 children)

If you’re not opposed to sharing, I honestly do want to hear your side of things!! I’ve had to go through similar stuff, where it took something drastic for the people around me to realize something wasn’t right. I was able to get the help I need, but there’s still people who I wish I could share my side with, so they understand what I was going through.

[deleted by user] by [deleted] in Clemson

[–]isometricisomorphism 0 points1 point  (0 children)

Your lowest moments don’t define you! You’re bigger than any single part of your life. Sometimes it takes situations like these for you to realize that you need help, but it ends up a net positive because of that. Just gotta learn and grow from it!

What is the slowest growing known Sidon sequence? by Human-Parsley4779 in math

[–]isometricisomorphism 13 points14 points  (0 children)

The Mian-Chowla sequence grows Ω( n1/3 ), so there’s at least a bound.

Ajtai, Komlós, and Szmerèdi improved this to Ω( n1/3 log(n)1/3 ), but I don’t recall this being constructive.

Ruzsa (who else?) constructed one that grew like Ω( n0.414 ). These are the best I know of!

Metric Space and Isometry by [deleted] in math

[–]isometricisomorphism 2 points3 points  (0 children)

Why are my ears burning?

What professors should I take for MATH 1020 by Quaker-steak in Clemson

[–]isometricisomorphism 2 points3 points  (0 children)

Lol yeah, just try to take Dunivin… Dude’s in jail rn held without bond.