A beautiful result of Ramanujan
2:24
e is irrational
1:58
2 жыл бұрын
Shortest Proof of Euler's Formula?
0:49
Abstract Algebra | 19. Quotient Rings
51:38
Stern's Diatomic Sequence
18:01
2 жыл бұрын
The Rogers-Ramanujan Recursion
13:34
2 жыл бұрын
Abstract Algebra | 12. Subrings
23:37
Пікірлер
@maydavidr
@maydavidr 11 сағат бұрын
I recently finished watching your video series on the Rogers-Ramanujan identities. Thank you for making these excellent video lessons. They are very good and your effort is appreciated. I plan to watch some your other videos too.
@KAWININBATHAMIZHJ.S
@KAWININBATHAMIZHJ.S 2 күн бұрын
thank you so much
@tesafilm8447
@tesafilm8447 17 күн бұрын
26:15 I thought the existence of a surjection is enough to show that the cantor set is uncountable because then the cardinality would be bigger than or equal to the cardinality of [0 ; 1] ?
@FloremsanguinisIt
@FloremsanguinisIt 26 күн бұрын
Hi, where can I find the article by Andrew and Baxter about the Rogers-Ramanujan Identities?
@petersiracusa5281
@petersiracusa5281 6 ай бұрын
Well presented.
@YuxiXie-f1e
@YuxiXie-f1e 11 ай бұрын
Will there be "next few videos"🥲🥲 I appreciate your work for this series so much. I have watched and taken notes for every videos in this series. Thank you for making those videos though there are not many people watching it! It's really useful for students who is learning the same book in this ring-group-field order. 😍🥰
@emkiral
@emkiral 11 ай бұрын
also I like
@YuxiXie-f1e
@YuxiXie-f1e 11 ай бұрын
The strongest for real❣❣💯💯
@YuxiXie-f1e
@YuxiXie-f1e 11 ай бұрын
Very sufficient and clear proof and explanations. I'm so pity that other students can't find this series or don't give it a look. Thank you for making those teaching videos!!
@YuxiXie-f1e
@YuxiXie-f1e 11 ай бұрын
At 1:40, shouldn't the multiplies of 4 larger than 24 is 28,32,36 and so on? I think you might accidentally write 30.🙂
@YuxiXie-f1e
@YuxiXie-f1e 11 ай бұрын
Thank you sooo much for making these series video!! You really explained it clearly, and all the proves are tidy and well-ordered.
@KaneJessen
@KaneJessen Жыл бұрын
Thank you for this quality video!
@JC-sg1do
@JC-sg1do Жыл бұрын
It is an interesting video. However, the content is old. I know a better solution, there is a 13-year-old boy has found the final solution for the integer partition problem. please check these links: kzbin.info/www/bejne/boqspJ-Ge7R1bpY ijcionline.com/paper/12/12423ijci06.pdf
@thomasjefferson6225
@thomasjefferson6225 Жыл бұрын
Heyo, after i understood this i saw the beauty in it. Damn, this shits dope.
@thomasjefferson6225
@thomasjefferson6225 Жыл бұрын
Took me 3 times, but I believe I understand this now.
@MattHatter-t5r
@MattHatter-t5r Жыл бұрын
Beautiful
@yagzhandag3803
@yagzhandag3803 Жыл бұрын
Great
@bartholomeosphinx4382
@bartholomeosphinx4382 Жыл бұрын
The Cantor function is NOT the "function that you see here".
@MatthiasBloch
@MatthiasBloch Жыл бұрын
Very nice job, thanks! I am currently working through the series and it helps a lot
@niyathalluri9301
@niyathalluri9301 Жыл бұрын
omg thanks 🙏
@feiqi1975
@feiqi1975 Жыл бұрын
Looking forward to your videos on inf-dim Lie algs.
@RikMinjauw
@RikMinjauw Жыл бұрын
Do you have some book references about abstract algebra with proofs included as done in this video ?
@mathilike9460
@mathilike9460 Жыл бұрын
Yes, these notes are based on and in a similar style to Abstract Algebra: An Introduction by Thomas W. Hungerford. It's a very solid first abstract algebra book with lots of good exercises, but is a bit different from standard texts because it teaches rings first and then groups (most books do it the other way around and teach group theory first).
@RikMinjauw
@RikMinjauw Жыл бұрын
@@mathilike9460 Thanks a lot for your response . Your presentations are very helpfully .
@EMMASAX35
@EMMASAX35 Жыл бұрын
This was really helpful, thanks a lot👍
@joypaul1976
@joypaul1976 Жыл бұрын
Great stuff 👌👌👌
@massahudujawol3891
@massahudujawol3891 2 жыл бұрын
Not clear
@user-xt3hl6vr2k
@user-xt3hl6vr2k 2 жыл бұрын
Thankyou so much for making this video. It helped me a lot! Please keep making these!
@cydhamletcamartin9638
@cydhamletcamartin9638 2 жыл бұрын
y
@kingsmen2678
@kingsmen2678 2 жыл бұрын
Thank you
@venkybabu8140
@venkybabu8140 2 жыл бұрын
Wave dampening is a surface phenomenon.
@2minutestomammoth
@2minutestomammoth 2 жыл бұрын
Don't you need stronger logic at 2:02? You've shown that this formula holds at any finite level of depth, but that doesn't necessarily imply that it should work at the infinite depth of the infinitely-nested root (because there's a large end value of f(n+k) that keeps getting replaced with new roots with every iteration). Is this really Ramanujan's original solution?
@mathilike9460
@mathilike9460 2 жыл бұрын
This was indeed Ramanujan's original solution in the Journal of the Indian Mathematical Society, published in 1912. And indeed you're correct, there is a jump in logic, which Ramanujan himself missed, and is addressed in this paper: www.tandfonline.com/doi/abs/10.1080/00029890.1935.11987745 A pdf of the paper pops up if you Google for its title and put pdf afterwards in your search. I'll add a disclaimer to the description about the jump in logic. The intent here was to just present Ramanujan's idea in the video, but for correctness, this must be pointed out as well.
@derickd6150
@derickd6150 2 жыл бұрын
Could barely concentrate on the proof cause the music is so dope. Love it though. My new favorite way to see a proof for the first time
@angelmendez-rivera351
@angelmendez-rivera351 2 жыл бұрын
An alternative definition of a group is a structure (G, e, ~, *) on G, where e is a 0-ary function, e : {0} -> G, ~ is a 1-ary function, G -> G, and * is a 2-ary function, GxG -> G, such that, with all universal quantifiers implied, and no existential quantifiers, x*e = e*x = x, x*~x = ~x*x = e, x*(y*z) = (x*y)*z. A motivation for this alternative definition, aside from having a completely equational signature, is the fact that group homorphisms can now be defined more concisely in terms of compositions. In my opinion, this should have been taught earlier in the series, prior to rings. This is because, once you have been exposed to group theory, defining a ring axiomatically is extremely simple. A ring (R, 0, 1, -, +, ·) on R is a structure such that (R, 0, -, +) is an Abelian group, (R, 1, ·) is a monoid, and x·(y + z) = (x·y) + (x·z) and (y + z)·x = (y·z) + (y·x). I think there is motivation to define rings in this manner: it helps explain why the multiplicative monoid of a ring can never be a group: because it is not a cancellative monoid. In fact, generally speaking, there is a fundamental difference between a cancellable monoid, and a non-cancellable monoid. A cancellable monoid may not itself be a group, such as with the nonzero integers, but it is _embeddable_ into a group, the group of nonzero rational numbers. A non-cancellable monoid is _not embeddable_ into a group. Multiplicative monoids of a ring with zero divisors excluding 0 are examples of this. If x is a zero divisor, then there exists some a such a·x = 0, so y·(a·x) = 0 = z·(a·x) = (y·a)·x = (z·a)·x, and so, if a is cancellable, then x is not cancellable. So zero divisors satisfying a certain condition are never cancellable. In fact, this answers an important question: why can a ring not be extended in such way that 0 can attain a multiplicative inverse and allow 0·x = x·0 = 0 to be false? The reason is because 0 is not multiplicatively cancellable. Extending a ring to a field can allow every cancellable element to have an inverse, but not 0 or other non-cancellable nonzero divisors.
@Alex_Deam
@Alex_Deam 2 жыл бұрын
The music really makes these
@anonymous-xm4gx
@anonymous-xm4gx 2 жыл бұрын
What is the motivation? Just trial and error?
@valentinziegler1649
@valentinziegler1649 2 жыл бұрын
Nice vid. There was just one small issue, wiping out the content at 0:45 just one second after proving your key point “N is a natural number”. I was unable to process the final line this quickly, so I had to rewind and pause. Maybe next time let it sit for a few seconds before transitioning to the next “slide”, or scroll the content so people get a chance to follow the argument.
@Nick-kg7sk
@Nick-kg7sk 2 жыл бұрын
Awesome proof
@bengilliland7048
@bengilliland7048 2 жыл бұрын
Can you explain why N < 1/n is a contradiction? The way I see it, N is n! multiplied by the error of approximating e by the sum of the first n factorials. I can't see why this is necessarily a contradiction
@RadixTheTroll
@RadixTheTroll 2 жыл бұрын
We proved early on that N must be a natural number. But later we show it is less than 1/n where n >= b. This is a contradiction because 1/n must lie between 0 and 1
@angelmendez-rivera351
@angelmendez-rivera351 2 жыл бұрын
N is a positive integer, and so is n. Since n is a positive integer, n >= 1, hence 1 >= 1/n > N. In other words, N < 1. But this is a contradiction: there are no positive integers less than 1.
@mrl9418
@mrl9418 2 жыл бұрын
The fact that N is strictly positive comes from the definition of e at the beginning. Sum of one over k factorial up to n , subtracted from e, gives a converging series of strictly positive terms
@theshoulderofgiants
@theshoulderofgiants 2 жыл бұрын
nice ♥ do one for e is transcendental next😝
@mathilike9460
@mathilike9460 2 жыл бұрын
That might be a bit longer, but I'll plan for it :)
@theshoulderofgiants
@theshoulderofgiants 2 жыл бұрын
@@mathilike9460 seriously 😳?? I was just joking seeing how transcendentality proofs are always very complicated and involved ...i think the simplest proof for transcendentality was in mathologers video
@mathilike9460
@mathilike9460 2 жыл бұрын
@@theshoulderofgiants Haha, I figured, which is why I said "a bit longer" :) Realistically, a transcendence proof is going to be way too long for this style of video. It would be fun to do a long form video on a "lesser known" proof of this fact, however. Michael Penn did a proof of the transcendence of e recently: kzbin.info/www/bejne/mpO0eX2ajdiEq5Y
@leif1075
@leif1075 2 жыл бұрын
Why would anyone start with this function e^-it to begin with?
@OnDragi
@OnDragi 2 жыл бұрын
Proving that a=b is equivalent to proving that 1=b/a (unless a=0, but here we know that's not the case). Same goes for functions, point-wise, and the trick part is that now you can derivate and just prove that something is 0, which can simplify things. And using derivatives is really quite natural for the exponential, since its relation with its derivative is in the very core of what even _is_ the exponential. So it doesn't come completely out of the blue.
@ian-haggerty
@ian-haggerty 2 жыл бұрын
The Taylor Expansion one sticks in my head from school, but this one was fun 😊. Albeit, done with massive amounts of hindsight. Not always a bad thing!
@matematica6pi
@matematica6pi 2 жыл бұрын
This proof relies on the validity of the real rule for the derivative of e^(kx) when we set an imaginary k.
@goovn
@goovn 2 жыл бұрын
Cool!
@lucatanganelli5849
@lucatanganelli5849 2 жыл бұрын
Wonderful. Better than solving for y''=-y.
@arcstur
@arcstur 2 жыл бұрын
Wow, nice!! Very clever this idea of proving equality by showing that the division equals one :D
@yuyurolfer
@yuyurolfer 2 жыл бұрын
I don't know why I got this recommended, but I love it!
@drvanon
@drvanon 2 жыл бұрын
Ha, that is crazy. Nicely executed with the music and stuff
@kubilayaytemiz7274
@kubilayaytemiz7274 2 жыл бұрын
Wonderful! Thanks.
@aoughlissouhil8877
@aoughlissouhil8877 2 жыл бұрын
Amazing
@Gejam_GameDev
@Gejam_GameDev 2 жыл бұрын
even Euler himself
@aoughlissouhil8877
@aoughlissouhil8877 2 жыл бұрын
@@Gejam_GameDev 😆😆
@MrGnome-ng6jv
@MrGnome-ng6jv 2 жыл бұрын
Ok
@MichaelPennMath
@MichaelPennMath 2 жыл бұрын
nice one!
@leif1075
@leif1075 2 жыл бұрын
Why would anyone think of starting with this f(t) to begin with?