Why -1/12 is a gold nugget

Featuring Professor Edward Frenkel. More links & stuff in full description below ↓↓↓
Okay, the links...
1. New vid on the Riemann Hypothesis explains where -1/12 comes from: • Riemann Hypothesis - N...
2.The original videos at • ASTOUNDING: 1 + 2 + 3 ... AND • Sum of Natural Numbers...
3. A useful blog from Tony Padilla: bit.ly/TonyResponse
4. NY Times article on this: nyti.ms/1iftqSv
5. Terry Tao on this topic: bit.ly/TaoAnalytic
Prof Edward Frenkel's book Love and Math: amzn.to/1g6XP6j
Professor Frenkel is a mathematics professor at the University of California, Berkeley - edwardfrenkel.com
Animation by Pete McPartlan
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[@sunofslavia]

"Euler was a mathematical gangster." - Prof. E. Frenkel

[@Asshat331]

+Pelle Olsson So you drink until 4 am and listen to gg allin and you are into advanced mathematics. You're neat.

[@KokoMbella]

thug life

[@Supperesed]

life iz a struggle

[@surferriness]

420 likes

[@mairisberzins8677]

Future plans set. I hope Mathematical gangsters get payed a lot :/

[@maxhedges4167]

Imagine being in an infinite job where you're paid 1 more dollar every day then at the end get a paycheck with - 1/12 dollars.

[@wcsxwcsx]

Ah, but the end is at infinity.

[@quranwithtajweed8575]

and lots of dirt

[@andrewprahst2529]

Ehhh, that series doesn't "equal" that perse

[@n.bourbakki]

It's all fiat money anyways

[@vasugarg863]

I prefer not to live till infinity.

[@karlmadsen3179]

"Does the square root of negative one exist? Come on, Brady." He taunts Brady with a glint in his eye and an evil grin.

[@Deniis]

i

[@farrel_ra]

To prove that this series sums to -1/12 is correct too.

[@masonhunter2748]

No it doesn’t

[@stretchyone]

@@farrel_ra I mean, what he says in the video is not that. Dude says not that it's The Answer, but that it is A Useful Answer, and that we could really use you do a lot more math to understand why exactly is a useful answer.

[@farrel_ra]

@@stretchyone more like more theoretical physics like quantum mechanic, but yeah.

[@toddgoul5857]

"There is magic, but we always want to explain it." What a perfect encapsulation of scientific endeavor.

[@adithyaramesh5634]

Amazing words

[@FosukeLordOfError]

Any significantly analyzed magic is indistinguishable from science

[@anhbayar11]

yeah humans.... always trying to find the answers

[@OfficialGOD]

that's what they are paid for

[@dodatroda]

And failure.

[@FrankenSteinsGate]

Russian Jaime Lannister makes some compelling points.

[@Que-E]

hahaha you are so right

[@chrischampagne9469]

Ha ha! I was thinking the same thing. But I thought his accent sounded Braavosian.

[@balsoft01]

I was thinking that he was Russian since I first heard his accent, but now I'm sure.

[@TheOneGoofAli]

Russians! (I'm also Russian. .w.)

[@lagduck2209]

Somewhat strange, but I understand J. Grime's accent better than this' obviously Russian speaker. (Although I'm Russian)

[@mattbritzius570]

He looks like a guy that would be taunting Bruce Willis over the phone in a diehard movie.

[@cosmonaut379]

lol I totally can see it

[@AndersJackson]

+Yung Brizzy and a lovely accent too!

[@DennisMathgod]

lol

[@oz_jones]

Simon says what is the square root of negative 6

[@Averlook]

w

[@jeck2628]

Euler did some painstaking work and lost his vision. After the loss of vision he said "Now I will have fewer distractions" Now thats gangster lol

[@kingbane2]

man this professor must be an amazing educator. he makes things so clear and easy to understand.

[@NormReitzel]

So did P.T.Barnum. This is the amazing Egress.

[@aidilmubarock5394]

@@NormReitzel egress?

[@ankyfire]

Indeed! I finally understood imaginary numbers

[@johnclever8813]

⁠@@NormReitzel Frenkel is no charlatan like PT Barnum. He’s one of the greatest mathematicians alive. He has an incredible mastery of a wide variety of subjects, and is a leading researcher in the Langlands program, with dozens of brilliant papers within it. Keep in mind that the Langlands program is already one of the deepest, hardest subjects to study within mathematics, and Frenkel is at its forefront. Not only this, but he has created many of the links between Langlands duality and mathematical physics. I can’t speak of any specifics (I don’t study the subjects he does), but I know enough to have a tremendous respect for him.

[@Marqui91]

His lectures are available online. He also has made a movie.

[@splitzerjoke]

"Euler was a kind of mathematical outlaw... a kind of a mathematical gangster..." Euler: don't worry dear Riemann, i`ll make 'em a proof they can't refuse... LOL

[@oz_jones]

*refute

[@elnico5623]

Euler has a dream

[@jimbo6238]

@@elnico5623 errm.. no!

[@hunszaszist]

"One thing which is important in mathematics is that we just can never leave [...] loose ends. [...] Mathematics is rigorous, and at the end of the day we are looking for a rigorous justification of everything. In other words, we are not content with just saying that there is some magic over there. There is magic, but we always want to explain it." Edward Frenkel, Professor of Mathematics I just... this... wow...

[@rogerphelps9939]

This is not rigorous. You don't cut off a diverging series irrespective of weighting function.

[@russellthorburn9297]

6:52 "Does the square root of -1 exist". I laughed so hard (in delight) when he said that because his point was made blindingly obvious by asking such a simple question. Elegance at it's best. I'd sit through one of his lectures any time any where.

[@jasminepandit9861]

i'd like, but it's at 169 haha

[@paulbennett7021]

Of course root -1 exists; we can conceive it, describe it, and use it.

[@rohangeorge712]

@@paulbennett7021 exactrly, we can concecve -1/12 describe it, and use it, its not the sum to the series, but its a special result. he called it regularized sum, although i dont like using the word sum. i would say it is a special result, and this is in fact the rieman zetta function. -1/12 is an important output of the series, kind of like a function, but its not the sum but still a very important number.

[@BrianHartman]

@@rohangeorge712 I don't really understand. He keeps referring to -1/12 as the infinite sum. But he says you get there by removing the infinite part. So -1/12 can't be the infinite sum, right? So what is it? Is it like a function, and you're just taking a slice of the series?

[@sebasbot01]

@@paulbennett7021 well you technically cannot take the square root of a negative number. The definition of i isn't √-1 but i²=-1 for a reason

[@amaze2n]

This man is BRILLIANT. The way he clearly explains complex topics in a language that is not his mother tongue is astounding.

[@insomnia20422]

finally someone says that -1/12 is not the sum of this but a asigned value THANK YOU

[@galacticswan]

I do not write in proper english but I wanted to state this to you : The sum is a binary operation, between TWO numbers, so anyway, each time you consider an infinite serie, you DO NOT add all it's terms to find it's value : you assign a value to it. The thing is that there are various ways to assign values to it. If you try to assign a value to the infinite serie 1+2+3+4+... by identifying it with the limit of its partial sums, you will fail (if you wanted a real value). But the interesting thing is that if you assign a value to it succesfully, then this value is -1/12 and it makes sense when used in physics. So it would be a mistake to consider that we just "assign" a value to it but could assign any one. -1/12 IS the value of it, in the sense that there is no other value that makes sense for this sum, and this is in itself remarquable and fascinating. Of course I do not fully understand it, but what I'm guessing is that 1+2+3+4+5+...=-1/12 via the zeta normalization in quite a similar way that "9=4" in Z/5Z.

[@v3le]

that's alchemy guys, not the maths

[@MrAlRats]

Just like we assign values to any other infinite series.

[@hildervitor]

@@MrAlRats But at least, for some series, the assigned number respect some logical convergence property. Saying that -1+1-1+1-1+1... equals 1/2 is arbitrary and so is this -1/12.

[@MismanagedFutures]

Sorry but if you think this about what term is more precise, then you missed the whole point of the video.

[@alexanderlindblad7322]

Numberphile has managed to take the subject I disliked the most in school and turned it into one of my favourite and inspiring subjects on KZbin! Bravo!

[@numberphile]

that's great

[@zain4019]

Numberphile for some reason that seemed like sarcasm without a ! at the end XD

[@heywoodjablowme1624]

that's great factorial

[@poiiiiiiiiiii3049]

James Flyleaf y u no like math... Unlike all the language and humanity subjects, math and science have a definite answer, as in if you are right, you are right. If you are wrong, you are wrong. There is no such thing in math and science where your are half right or wrong, which is what I love.

[@adeshkantha7034]

lol y do u have such a problem with the subject of sums of infinite divergent series

[@OldSchoolCancer]

his accent just make everything better

[@hiroshimagiggity372]

yeah... it's kinda soothing to listen the explanations through that piece of particular pitch and frequency

[@Pe6ek]

Makes.

[@expensivetechnology9963]

I respect this professor’s mastery of my language (English), his second language, in addition to his mastery of mathematics.

[@numberphile]

Watched the whole video? Seen the links? Watched the other videos? Then why not leave a comment! :)

[@PrimusProductions]

***** Except -1/12 is meaningful in physics. The Riemann zeta function is used in the Derivation of Casimir effect with s=-3 and that gives 1/120

[@PrimusProductions]

Look up Derivation of Casimir effect assuming Zeta regularization. You will need to sum n^(3-x), let x=0 and rewrite as 1/n^{-3) Now you can input -3 into the Riemann Zeta Function and get 1/120

[@PrimusProductions]

***** You are wrong, the Casimir effect has been demonstrated. The sum of natural numbers being infinity is intuitive but it is not useful. On the other hand -1/12 is counter-intuitive but is used in Quantum Electrodynamics and Quantum Field Theory with the derivation of the Casimir Effect

[@PrimusProductions]

***** Fine, derive it here without ever involving -1/12, go ahead.

[@Rimmer7]

***** Your entire objection is "it's not that way, cause I said so." Why would I take you seriously?

[@opmike343]

The best explanation of this -1/12 business I've ever seen. There IS a lot more going on here than some of the other professors did a poor job of articulating.

[@thisaccountsucks5556]

I still don't get exactly how the -1/12 number is obtained.

[@xnalebb]

Yeah he didnt explain how they got it at all. Thats what I was curious about.

[@sanskarjain9455]

The best explanation I’ve seen personally on how the -1/12 figure is obtained from the zeta function and the analysis of Complex Functions Mr.Riemann and the rest were involved in is the video on Analytic Continuation by 3blue1brown. It’s worth a try.

[@andresdelagarza8600]

xnalebb @RubalCava Eddie woo explains a way

[@timh.6872]

I think the most enlightening way is to take the integral of the closed form of the finite sum of positive integers, (n+1)(n)/2 between its zeroes, 0 and 1. This value ends up needing to be the linear coefficient of the closed form of the sum of squares, and its integral gives us the linear coefficient for the next power, etc. This makes sure that the closed form "lines up" with the finite sum. Because they form a crucial part of the coefficients of Faulhaber polynomials (the fancy name for the closed forms of sums of natural powers of positive integers), they're related to the Bernoulli numbers, which are related to the zeta function. Basically, if you're going to be summing a power of consecutive integers, the zeta function is gonna sneak in there somewhere.

[@LostAlienOnEarth]

I just watched Srinivasa Ramanujan movie, "The man who mew infinity"

[@Crustyislooking]

We used to “throw away” negatives, I wonder if someday looking back we’ll understand those series better

[@jinjunliu2401]

we do?

[@MonzennCarloMallari]

Heck a very long time ago the concept of zero was controversial. We just move concepts from controversial to accepted in certain contexts.

[@michaelzimmermann9804]

I am a physicist and I deal with quantum-electro-dynamics (QED). I want to share with you (or show you ) the existance of a finite value for divergent sums. In QED we calculate vertices (meaning something like electron interacts with another electron via one photon). And we can calculate the magnitude of this interaction. But if one includes fluctuations (which are known to be omnipresent) we always get infinity. The vertex "electron interacts with itself via a photon" is for instance always infinite and can be added to any interaction. And now the above video comes into the game. We can renormalize the infinte sums just the way described above. and the outcome of the theory is absolutly impressive. QED has given values of physical constants up to the 14 spot behind 0 correctly, compared with experiments (which is unreached in any other physical theory). Therefore the existance of finite values for divergent sums is not a mathmatical fantacy, it is the TRUE reality.

[@michaelzimmermann9804]

oops... I should ahave watched the video to the end before responding.., he mentions what I just described :D sorry..

[@user-he4dk4sb7h]

And that's why Pauli-Villars and Hadamard Regularization exist.

[@sciencewithali4916]

@@michaelzimmermann9804 Don't know if it is okay to bother you with subject 4 years after your work, but i really wish you can add more precisions and details about your explanation

[@karebuu1383]

Wonderful

[@subscribetopewdiepie4109]

Michael Zimmermann doesn’t renormalization depend on experiments???

[@antaed27]

the most interesting video i've seen for a long time. fascinating stuff, thank you

[@numberphile]

glad you liked it

[@aaronstone628]

Numberphile what is the weird S notation thing on the board?...

[@nosuchthing8]

No question. Mind blown.

[@axe_y]

GameOver That would be an integral for your knowledge.

[@Supware]

+GameOver I think that's a zeta.. Looks like a description of the Riemann Hypothesis with the Re z = 1/2 at the bottom

[@Yupppi]

This guy is very fun to listen to. I get excited about the way he's explaining these concepts.

[@RozarSmacco]

The Prof. wields the English language like most native speakers could only wish.

[@samuelluria4744]

Marshall Harrison - Guitarist - Sadly, 98% of English speakers don't even recognize the utility, or beauty, of wielding the language. They kinda notice when they encounter someone twice as articulate as themselves, but hardly discern when someone's command is twenty times that.

[@lEGOBOT2565]

@@samuelluria4744 source for that statistic?

[@samuelluria4744]

Eric Williamson - It's my own lifelong attention to the empirical evidence.

[@lEGOBOT2565]

@@samuelluria4744 you can't cite yourself

[@samuelluria4744]

Eric Williamson - It's not a citation. It's an assertion.

[@symbolxchannel]

-1/12 reminds me of matrix determinant… It is a non-intuitive number that isn't the regular way to say "this equals that," but is still an essential "identity". I don't think the equal sign (=) is the proper way to represent this, since we defined *equal* as "considered to be the same as another in status or quality". In this case, the "1 + 2 + 3 + 4 + 5 + …" does not equal "-1/12", but is in a way the equivalent of a determinant (as with matrix). It is a property, but not an equivalent. The equal sign (=) isn't the proper sign… *It is only my opinion… I am not a mathematician.* Am I wrong? What do you think?

[@Examantel]

The notation is a surface complaint, and I think it shifts the problem elsewhere. The root problem is the difficulty with reconciling the philosophical nature of infinities. We have an intuitive understanding of sqrt(-1) as a number on a 2D plane, which is why we accept complex numbers without much problem. We know what the determinant of a matrix is, as it is a finite value and has useful properties in linear algebra. Once you get into infinities, there is a huge barrier with what infinity actually "is" and how this is communicated. For example, the idea of "potential" vs. "actual" infinities. An actual infinity is that which is realized as a mathematical object in some independent reality which can be reasoned with and manipulated. A potential infinity is something which can be constructed in the human mind, that is, a series going on forever without end, and cutting it off at some point lands you back into the land of finite numbers (partial sums). What we found with actual infinity is, by accepting their existence, it yields a bunch of mathematical results that have applicability everywhere from number theory, to actual, experimentally measurable phenomena in physics.

[@dude157]

It's much easier to accept the answer on an intuitive level, when you think of the result as a number that describes the series, or describes a certain property of the series, rather than the actual sum. Whether or not it is the actual sum, is like asking whether or not the square root of -1 is a number. Mathematics is so crazy, I like that nature can spring up essentially patterns that exist, that blow our intuition out of the water.

[@Squeaky_Ben]

Well, there is an = there, so by mathematic law it means that the mathematic operations on the other side of = equal the number on the left. If we had a "describes as" symbol I would be fine with this, but what he is showing here is nonsense. And yes, I get it, "a root cannot be negative" and such have held us back and its important to push boundaries. But, if you are gonna push boundaries, then do it well.

[@MrAlRats]

The sum of any infinite series is a matter of definition. If we adopt the definition of the Ramanujan summation, then the sum of all the natural numbers is -1/12. It's no more "nonsense" than assigning values to any other infinite series.

[@yosefmacgruber1920]

@Håkon You can not simply divide ∞/∞ because that is an indeterminate form. We need more information to know what the answer is, nor is there any reason to divide by ∞ anyway. ∞/∞ ≠ 1, because ∞ is not a number, but a concept. It does not cancel out, unless it can be shown that both the numerator and the denominator are the same variable which can be treated like a number. Look at the formula to find the slope of a line via 2 points on the line. The line already has the slope that it has. But let's lose some of the information, so that we have 2 points that are actually the same point. Then we have (y2-y1)/(x2-x1) = (y1-y1)/(x1-x1) = 0/0. The slope through just one point on the line, can be any slope that you would like for it to be. 0 slope, positive slope, negative slope, infinite slope. But only one of those answers is the correct one. The line can only have but the one slope that it has. It is not the fault of the line, that you were careless and did not gather enough information about it. But the one point does not give us enough information to determine what the slope of the line is.

[@georgesimpson1406]

it needs more symbols then, not just an equals. I even get how infinities cannot equal other infinities, there are different values to them....(but that's different notation, right?) and someone to describe why -1/12, how you could apply it in some function, why is squared 0 and cubed 1/120? what relation do they have? what is one of these examples where you can put this in as a replacement for infinity and come out correct, and how? If its some kind of descriptor why is it minus, after 'removing infinity'? how is infinity removed? obviously not by subtration or division! nor by turning it into a function or subsection or an average. -1/12 is outside, not even inbetween, not a single subtraction sign in there.....what does it represent then? then i might accept the answer!

[@PurtyPurple]

​@georgesimpson1406 I think these are the perfect kinds of questions you bring to your professor's office hours XD Man, mathematics is wild.

[@Turd420]

I love how mathematicians have no borders, infact, I feel that many mathematicians are defined into a position in which they can only converse with a select few on this world. Math is a beautiful language! I hope to learn more of it by the time I pass.

[@danjacobwallace]

Best discussion I've seen yet on this topic. Also, Frenkel's book (Love and Math: The Heart of Hidden Reality) is excellent!

[@sergiuconstantinescu8124]

I did not know he wrote books, thank you for this information!

[@davidndiulor8428]

what do we do with a divergent series? we just ignore them. good advice.

[@Riseky]

_video ends_

[@smritisivakumar3291]

How can you just ignore it ?? It bothers me horribly !!!!

[@AndrewPRoberts]

The books or the movies? Or just both?

[@sumitshingare7484]

@@smritisivakumar3291 hey !

[@sumitshingare7484]

@@smritisivakumar3291 I'm also from India do you wanna discuss pure mathematics?

[@oafkad]

I would wrestle a bear to sit in on a lecture by this guy. I love his presentations.

[@iamTheSnark]

Try Fozzie Bear.

[@phasepanther4423]

I'm really enjoying his voice too. What accent is that?

[@SquashBox]

@@phasepanther4423 He's from Russia. And then he moved to the US to work on his PhD.

[@oggassaggaoggaffa]

@hey, folks! That can be arranged. It's UC Berkeley after all.

[@Blox117]

STRONK MATH! KOMRADES, RUSSIAN MATH SUPERIOR TO DECADENT CAPITALISTIC RUBBISH.

[@richarddeese1991]

Cantor is another example of the prof.'s outlaws. The thing most non-mathematicians don't know is that the math that gets presented (such as in published papers, lectures, classrooms, etc.) is the "finished product." It seems clean and neat and perfect and irreducible - precisely because some mathematician (or more than one) toiled away at it (sometimes for years - even decades) to figure it out; it's clearest, simplest form, it's implications, etc. I've heard the process of doing math likened to a restaurant. Most of us sit in the dining area; we only get the finished meals. We never see the chaos that goes on in the kitchen! Can you imagine what a chef goes through? Experimenting with different ingredients, failing time and time again - until, finally, AHA! The perfect dish! That's what doing math 'feels' like. We aren't simply given the answers! We have to work at it - often fumbling around, until we get it right. Of course we're only going to present the world (that is, other mathematicians) with the completed, perfect recipe! Anything would be an embarrassment! Doesn't mean it's easy! And, as often as not, we STILL don't understand ALL the implications of our own discoveries; we may never do so in our own lifetime. That's the way it goes, kids. tavi.

[@stopper0203]

This has always intrigued me and I've done a bit of research here and there... but hearing Professor Frenkel explain the topic is a piece of gold in of itself!

[@UnashamedlyHentai]

This guy is one of my favorite guests on numberphile.

[@MrAkashvj96]

This is far & away the best Numberphile video out there & I've seen every single one multiple times.

[@BenInSeattle]

Once you've seen them -1/12 times, you'll know you've finished.

[@caspera3193]

After spending an infinite amount of time at the office, I received a salary of -1/12. I was forced to pay it in gold instead of euros.

[@MasterofBeats]

Oof

[@TristanCleveland]

This is excellent.

[@Claire-ing]

This helped a lot. I've seen way longer videos on this that only confused me more. This at least gave me a basic sense of what's going on here through the use of analogy and discussion of context and explaining that even by mathamaticians and physicists may not have this fully understood.

[@neogeo8267]

I feel so cheated by the public school systems for not teasing my mind with maths more as a child. When I revisited my education in my mid 20s (went back to school for my own enrichment) I was introduced to calculus I saw the horizon that is the magic of maths pushed well beyond by perspective at that time (and today). I do so wish I had seen that much earlier in life and now struggle to make up lost time only wishing I had more of it to do so.

[@jeffwells641]

+George Viaud Unfortunately, a love for math gets beaten out of children at an early age, and very few people find it again once they lose it.

[@clockworkkirlia7475]

+Jeffery Wells Yeah... I'm in love with numbers and mathematics, but the subject Maths is just agonising.

[@bzqp2]

That's probably Dewey's education system you attended. Too bad it's used in the USA :(

[@karlmadsen3179]

You have taken the integral of your life and found out there is an upper limit. You only find out what it is at a moment before your death. But how long is that moment? Ahhhhh. That's the question!

[@mohammadazad8350]

I'm 18 and I barely understand the true meaning of calculus also I'm like the worst in geometry, but no way I'm gonna stop studying, there is no late time.

[@puupipo]

Wow, probably one of my favourite Numberphile videos of all time. Very eye-opening. Thank you.

[@numberphile]

thanks

[@pimpomresolution5202]

Wow. He really makes this clear in a way I haven't heard before. I have heard the explanation that this sum is actually -1/12 mod infinity before, but I never understood what that meant. When he gave the example of slicing off the infinity of dirt and just keeping the nugget, something just clicked. We already know from Cantor there are levels of infinities, so why couldn't this value be -1/12 in some finite field analog from a higher infinity where the lower infinity just happens to be the modulus? I hope to hear a lot more from Professor Frenkel. Really like his style.

[@fulufheloratshisindi2102]

The analogies of prof Frenkel are brilliant. They just clear out everything. He is very clear in explaining!

[@trudyandgeorge]

On Facebook I received some backlash when I posted my amazement that the zeta function can assign -1/12 to the sum of all natural numbers (zeta(-1)). I am just as surprised at the backlash as I am about the -1/12 value. I can better-see how the discoverer of irrational numbers must have felt when they were ostracised long ago. I wonder if Reimann ever copped-it over his -1/12 value? Edit: Thank you, Brady. I love your videos. Keep it up, mate!

[@MMorgattto]

you can get backlash on facebook for saying 1+1=2

[@LosPrimosStar]

+MMorgattto You numberist oddophobe

[@chilldude5949]

no sum of positive numbers is smaller than any number included. the sum of all numbers is not less than zero, unless you ask a faulty function. maybe that's why they didn't agree with you, it's not correct.

[@CP-hd5cj]

+chill dude woosh

[@chilldude5949]

i is legitimate in every context. it stands in for sqrt (-1) so that operations can be performed on it to give it a real value. this value was obtained through error.

[@MuffinsAPlenty]

I think this is my favorite numberphile video because it explains so well the process of mathematical development and gives a glimpse into mathematical thought processes that most people do not see.

[@Yerrik]

Thank you for making these. They're totally amazing.

[@Chunes3]

Professor Frenkel is the best person I have ever seen at explaining things. I could watch him speak all day man

[@michaelp9676]

"Euler was a kind of a mathematical outlaw... a mathematical gangster"... lol MUCH better explained than the previous video and some good humor. Well done.

[@benitorossi1076]

Topo gigio

[@AgglomeratiProduzioni]

Maybe the sum of all the natural is -1/12 just because the Universe's calculator overflows.

[@titubakom]

+Ruben That may have been a joke, but so far it is the best explainaition of why replacing infinite series with -1/12 works!

[@inthefade]

+titubakom It really is.

[@clockworkkirlia7475]

+Ruben Honestly, with my limited understanding of this, that could be correct. The Universe may not actually have a perfect mathematical system, and this is one of the "bugs". That's not the way I prefer to think about it, but it''s consistent with what we know about the universe.

[@bamless95]

this implies that we live in the matrix

[@bittertruth_or_sweetlie5739]

physical world is illusion which appears in eternal universal consciousness..#pseudo_logic

[@fleaship6134]

This guy speaks with passion, it's videos like this that inspired an interest in mathematics for me.

[@per-axelskogsberg3861]

More of this guy. Context is extremely important. Also videos about Riemann, analytic continuation and so on.

[@danielmonadssuck3337]

Awwwww, I was hoping we would get see this thing in action. Like some problem you used -1/12 to solve, then showed an alternate path to prove that the answer was correct.

[@triforce9856]

excatly, ur not an expert

[@christophergudgeon9902]

-1/12 is a gold nugget? (puts -1/12 into calculator) (gold nugget appears)

[@EpzilonZ]

+Christopher Gudgeon Almost everyone tried this now.

[@bilalbaig8586]

dont use a ti85 or you are gonna lose your money

[@skhumbuzocele1330]

Bilal Baig .....Mathematician are funny😂😂😂😂😂😂😂😂😂😂

[@FourthDerivative]

Mathematician discovers one weird trick to generate endless gold (economists hate him)

[@themaverick1891]

Petty lies just to get some comment likes.

[@hourplastic4546]

The fact that there are many levels of infinity I can actually almost believe it, not understand it, but believe it.

[@ineednochannelyoutube5384]

The easiest way of picturing it is an infinite line as opppsed to an infinite plain defined by two infinite lines. Thesre are of course many more, and these two would fall into the same category under xertain classification, but it is easy to see how one differs from the other fundamentally.

[@jaakkosaarela9331]

It is always troubling when the support for an argument is "there are many examples...", but none of the examples are presented.

[@thatsagoose4039]

Too complex for this video. If someone was curios they would look it up

[@x1PMac1x]

This professor speaks so well and looks at the camera just right. I really was able to absorb the whole topic. Thanks so much for this. I hope he can speak about another interesting topic soon.

[@peterwharton1161]

Great video. I could never reconcile this result in my mind but the context explanation and comparison to complex numbers really helps!

[@derekfrost8991]

Euler was a mathematical gangster. He was the father of mafiamatics.. :)

[@aqwaa3057]

This is what I love about maths. It’s so logical yet so bizarre. By the way he did a great job explaining such unordinary topic in a way, that even I can follow the ideas.

[@TheDarkerPath]

Love that you gave plenty of time in the edit for Prof Frenkel to talk. Great stuff!

[@unvergebeneid]

I really hope this whole affair didn't discourage Brady from covering mind-blowing topics because there are so many of them left. Maybe the take-home message from this is that it's ok to blow people's mind but it's a bad idea to leave them out in the rain with the crazy fact you threw at them just because you thought that would make the whole thing seem even more impressive.

[@m3keita]

Is it established that Euler had ever stated that "1+2+3+4+.... = -1/2"? if yes, where/when?

[@geminijake7398]

3:05 yes make a distinction. -1/12 is a regularized sum Infinity is the naive sum... This is what folks had difficulty with.

[@HasanAlicik]

Actually you can see why. The teachers/professors/the people who tries to explain it to whom did not understand it, does not explain it like that, they are explaining it like it is literally -1/12. I look at the topic like there are several realms of mathematics, like these two. In one of them it is equal to infinity and in one of them it is -1/12.

[@PickyMcCritical]

Hearing this guy come up with analogy after analogy to justify -1/12 is like listening to a person with sight trying to describe color to blind people. I really feel like he gets it. Maybe it'll make sense for me one day with enough analogies and experience.

[@ButzPunk]

I love Professor Frenkel's accent and the way he explains complex mathematical concepts like this so amazingly well, so that even things that seem to make no sense suddenly make so much sense.

[@thepunk7106]

This explanation has made the most sense so far regarding why and how this sum can be said to be -1/12

[@AroundTheBlockAgain]

Another big thank you to Prof. Edward Frenkel! I was still pretty baffled about this after a couple Numberphile videos about it, but his explanation helped the pieces fall into place in my brain.

[@macurvello]

This explanation is way more acceptable than the ones in the other videos! There is actually something unknown about the subject. It's not just "Hey, this divergent sum equals -1/12, period"

[@macurvello]

+Marco Curvello Ok, maybe the previous videos weren't so simplistic as I implied, I exaggerated. But still, my point remains the same.

[@michaelawilliams]

What it proves is that the math is wrong and that these guys are idiots for thinking any differently.

[@mikosz666]

This man must give fascinating lectures. He seems to have an exceptional ability in explaining mathematical topics. I love his answer to Brady's question about "breaking the rules" when calculating divergent series. I'm definitely buying his book soon.

[@satyamtekriwal7376]

I think of it as other way of defining properties of a function. Like you can take a function and you can it's gradient, it's slope etc. Here you have properties of a function and you use it to find the value. Like when you have antiderivative of a function you can integrate it to get the actual function, it might not be *exactly* same but it's almost the same function (calculus assume that everything is smooth If you zoom far enough, which might not be true for every function)

[@praveenvijeyakumar741]

This video single-handedly gave me all the closure I needed about -1/12. The analogy with the square root of -1 was perfect. Thank you!

[@vellyxenya3970]

Man, I've never seen someone explaining this sum as well as you do, thank you!

[@Doc_Fartens]

Really enjoying Professor Frenkel's explanatory methods. If almost any other professor tried to explain this concept to me I'd be more lost than Malaysian Airlines. Too soon?

[@ogtw]

too soon... too soon...

[@Jorissoris]

Nah, it was only like a week ago....

[@filwe6575]

You just made my day! haha

[@abhisheksankhla2942]

Amazed by how proficiently Professor summed such infinitely deep concepts in nice finite words.

[@anshumanabhishek5177]

The explanation is just GOLD

[@ze_rubenator]

This is proof that a base-12 system is the most natural. Not really, but I like the idea.

[@GustavoValdiviesso]

There, this is a fulfilling explanation! I loved the point of view and choice of words of Dr. Frenkel in this video. Very well done!

[@mathsplank6087]

I just love the passion with which he is talking about mathematics...

[@alemutasa6189]

This video is the perfect explanation on why math is a tool, first and foremost, in the sense that "if something works we'll use it". Before taking Calculus at my university I always saw math as something mystical and arcane, but thanks to explanations like this one I finally overcame my fear and started taking real interest in this beautiful subject

[@ChrisBandyJazz]

Watched the whole video. Thank you so much, Dr. Frenkel (as well as Mathologer) explained this issue the best I have ever heard. Too bad the Ultra-finists mis-quote him. :(

[@jackren295]

I agree. The way mathematics (and physics) relate the ordered sum of all natural numbers to the value -1/12 isn't saying that they are equal to each other, but that the process of summing has some characteristics that can be represented by -1/12. This characteristics is unique even if you change your approach to finding it, as many (if not all) methods of assigning finite values to that sum yields -1/12. And this result is useful in physics as it can help us describe and predict the events in the universe.

[@jowbloe3673]

@@jackren295 - Absolutely no explanation was given to how the value of -1/12 was arrived at, which was the whole reason I wasted 15 minutes watching the video.

[@Nat-br7zo]

@@jowbloe3673 I mean, it's a very deep topic, that majority of the viewer wouldn't understand. I don't think you'd understand either.

[@w4yland3r27]

@@jowbloe3673 they have a bunch of videos to show it. This is more philosophical

[@pedrogarcia8706]

@@jowbloe3673 numberphile already has 2 other videos on the topic that this video mentions that the beginning.

[@flookaraz]

I lost it after he said 'mathematical gangster'

[@flookaraz]

ThisIsRTSThree999 due to my brain having been put in a blender when I was 8, I am confused by your response

[@journeymantraveller3338]

Ramanujan calls this "regularized sum" the "constant" of a series. It seems to be capturing some sort of defining characteristic of the series.

[@jamesdean1143]

Thank you for mentioning Ramanujan, as I vaguely remember him sending this solution to Hardy, and Hardy and Littlewood both laughed. But, this should have been well known to both of them by 1913 ?

[@renatobergallo6321]

This is one of my favorites videos on KZbin

[@eyemagistus]

Sounds like the solution to the national debt!

[@Nat-br7zo]

@Håkon r/whoooosh

[@lusayonyondo9111]

Lol...

[@beautifulcarpetdiagram]

Imagine presenting national debt as the sum of prime numbers

[@brucereinhold9564]

Thanks. The analogy drawn between the square root of a negative number and renormalization of the naively infinite sums by the construction of a more inclusive mathematical setting was just beautiful in its phrasing. Bravo! I'm nostalgic for my course of complex analysis many decades ago. Talk about a nugget of gold in the infinite dirt of the internet.

[@sarahdaviscc]

Professor Frenkel is really interesting. I'd love more videos with him.

[@Yora21]

Now I finally understand: The answer is "we don't know why".

[@AmericanHero911]

Mathematical gangsters like me got thrown in jail for spilling the beans on -1/12

[@stephenbianchi7141]

5:10 I always forget what comes after 2, bro. Don't feel bad.

[@a4genuch990]

When you are so used to being a mathematical gangster, it's hard to count to ten

[@ximono]

😆 I know the best mathematicians are bad at arithmetic, but that was painful.

[@sandorrclegane2307]

I really enjoyed listening to this professor. Gotta check him out

[@UmJammaLamma]

Nice to see some closure on the whole -1/12 controversy!

[@redo348]

It seems to me that the mistake is to think that the usual rules of mathematics are "real". Addition, multiplication etc. are also abstract concepts that were invented by people. 2x5=10 in the sense that you get that answer if you follow the rules. It's also "real" in the sense that those concepts can be applied to real things, which is what makes mathematics so useful. It sounds like 1+2+3...=-1/12 is real in the same sense, if a little harder to picture.

[@AlanKey86]

Now that imaginary numbers are "out the bag", Numberphile's surely got to explain that old chesnut: e^(i*pi) = -1 or as my maths teacher used to prefer: e^(i*pi) + 1 = 0

[@wollf92]

I think every mathematician prefers the e^(i*pi) + 1 = 0

[@Vulcapyro]

The core of that identity, and the more interesting part really, is the formula Euler (or Cotes, perhaps) presented: e^(iθ) = cosθ + isinθ As can be seen, when θ=π then you have e^(iπ) = cosπ + isinπ = -1 + i(0) = -1. This also results in e^(i2π) = cos2π + isin2π = 1, and e^(iπ/2) = i, and so on.

[@Momohhhhhh]

Well, the specific case for pi comes from Euler's formula e^(i*x) = cos(x) + i*sin(x). Substituting pi for x gives -1, because the sin term vanishes and the cos term evaluates to -1. As for where the more general Euler's formula comes from, I don't know for sure, but it can be proven by comparing the Taylor series expansions of either side of the equation. It comes from calculus though, and I'm not sure whether Brady typically includes calculus topics in the Numberphile videos.

[@MeanHacker]

Its tied with one of Euler's equations

[@VechtMalthos]

Or the /real/ identity, e^(i*tau) = 1

[@JosephMainusch]

Best answer I've seen so far: (paraphrasing) "We don't really understand it." We should not be afraid to say we don't understand something.

[@RSLT]

Great Job! Well explained!!! Thanks for the excellent and cool explanations.

[@mattv2099]

I love this channel. awesome stuff.

[@felicvik9456]

Are ya a bot?

[@felicvik9456]

@Fremen no

[@Pr1sk1]

These has been most intresting videos in mathematics I have ever seen. It's disturbing, counter-intuitive and facinating. Also it ties quantum physics and mathematics together in ways that I did not expect.

[@danishsharma0373]

That's such a compelling demonstration from proffesor

[@aarthiandahalf]

Thank you for this explanation!

[@Starman256]

its like nikolaj coster waldau and martin freeman had a baby and raised it in russia

[@nanigopalsaha2408]

Raised *it*?

[@Starman256]

@Fremen theyre both popular actors. Nikolai played Jaime Lannister in Game Of Thrones and Martin Freeman played Bilbo Baggins in The Hobbit

[@mikekeenan8450]

This is the best explanation I've seen of this weird idea. I like his take on the matter.

[@dneary]

I love that the rigorous mathematical framework that he talks about is up on the board behind Prof. Frenkel.

[@kartikamarjeet2082]

He has awesome command over English. What I liked most that he called imaginry numbers 'imaginry' without any worry, unlike many other videos. Though, imaginry numbers are as real as other numbers, but I have seen so many videos where I see that it would be explained that we should not think of these numbers as imaginary. He didn't emphasize on that. People like me who learn from these videos will certainly say something about as we are influenced by these videos.