The Shadowy World of Umbral Calculus

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  • Опубликовано: 3 янв 2025

Комментарии • 419

  • @nbspWhitespaceJS
    @nbspWhitespaceJS Год назад +63

    Umbral calculus is truly a shadow of school calculus. I played around with umbral calculus and discovered that the sequence 2^n is its own difference. Therefore, 2^n is a shadow of e^x. Really cool.
    EDIT: If you apply newton's forward difference formula to 2^n, you get something that is disturbingly similar to the maclaurin series for e^x

    • @Supware
      @Supware  Год назад +7

      Yep! This is a special case of the stuff I talk about at 12:00ish in the video (a=1) :)

  • @krhino42
    @krhino42 2 года назад +125

    “By rearranging the question, we get the answer.” Imma use that

    • @Qreator06
      @Qreator06 2 месяца назад +10

      All of math in a nutshell

  • @al.7744
    @al.7744 2 года назад +378

    You explained the topics enough to understand what was going on and showed barely enough for us to be intrigued and interested in this without us getting really spoiled or you being tiresome. I am fully convinced to at least attempt and learn more from these fields eventually because of this video. I cannot help but praise you

  • @elkinmontoya9640
    @elkinmontoya9640 2 года назад +66

    There is so much mystique in this area. I feel like there is a mystery that is just lurking, waiting to be discovered. I see little tidbits of group theory conjugation, analytical combinatorics, probability density functions, so many paths begging to be traversed. From a personal point-of-view, so many potential application to physics

  • @lexinwonderland5741
    @lexinwonderland5741 2 года назад +53

    this is SO much better than the wiki page. It left me fascinated (even moreso than Dr. Michael Penn's talks on the matter), and honestly someone should REALLY add the homomorphism between discrete and infinitesimal calculus you described here to the wiki AT THE MINIMUM. thank you so much for the contribution to math education!!

    • @Supware
      @Supware  2 года назад +5

      Wow haha thank you! Guess I've no choice but to keep it up :)

    • @pauselab5569
      @pauselab5569 9 месяцев назад +1

      it's already there but not much on it. like 3 line paragraph style

  • @魏寅生
    @魏寅生 2 года назад +15

    I've been struggling with abstract algebra and your video presents a perfect example for why isomorphisms are useful! Really appreciate it!

    • @Supware
      @Supware  2 года назад +1

      Great to hear!!

  • @vladimirmakarov9849
    @vladimirmakarov9849 2 года назад +69

    Absolutely fantastic video. The Newton difference formula derivation was simply amazing, i used it before but never knew where it came from and this was just the cherry on top. Can't wait for the follow up!

  • @fabiant.2485
    @fabiant.2485 2 года назад +116

    In the sci-fi rouge like rpg "Caves of Qud" dark calculus is a forbidden field of mathematics, because it's study opens a path into a transcending layer of reality inhabited by an infinite ocean of psionic minds...
    After watching this i am impressed by how accurate to real life the devs made their lore.

    • @jayst
      @jayst Год назад +5

      I could feel my Glimmer rise after watching this

    • @cerulity32k
      @cerulity32k 3 месяца назад +1

      dark and EVIL calculus 😨

  • @corbinsmith5015
    @corbinsmith5015 2 года назад +30

    I love umbral calculus and generating functions. Ive been reading George Boole’s book on the calculus of finite differences, and I really appreciate videos like these which make the ideas more accessible to the general public

  • @TheRationalPi
    @TheRationalPi 2 года назад +176

    Oooh, this seems like it could have lots of utility in digital audio processing, since you're regularly moving between the discrete and continuous domains.

    • @Supware
      @Supware  2 года назад +48

      Interesting, I'd love to see more practical applications of this thing

    • @OdedSpectralDrori
      @OdedSpectralDrori 2 года назад +24

      brilliant direction. time to see how these transforms would help analyze some filter and the fourier transform

    • @Supware
      @Supware  2 года назад +20

      @@OdedSpectralDrori don’t quote me on this but it seems the Laplace Transform is VERY relevant here :p

    • @OdedSpectralDrori
      @OdedSpectralDrori 2 года назад +20

      @@Supware this will make a fine quote

    • @Supware
      @Supware  2 года назад +9

      @@OdedSpectralDrori what have I done

  • @johnchessant3012
    @johnchessant3012 2 года назад +37

    Very nice! The example of umbral calculus on the Wiki page is pretty cool too, it relates to Bernoulli polynomials B_n(x) which satisfy the identity B_n(x) = (B + x)^n, i.e. B_n(x) = sum (n,k) B_k(x) x^(n-k). And you can actually simplify some proofs of identities involving the Bernoulli polynomials by doing "calculus" with this umbral notation.

    • @Supware
      @Supware  2 года назад +6

      They’ll be appearing in the follow-up!

  • @diogeneslaertius3365
    @diogeneslaertius3365 2 года назад +3

    Thank you for the video! I spent like 45 minutes going over the video, writing everything down, checking.
    It was a great experience. Please make more videos like this one, including the follow-up video on the Umbral Calculus.

  • @discreet_boson
    @discreet_boson 2 года назад +7

    One of the best SoMe vids yet!
    I literally just learnt about the binomial theorem and summation, intriguing to see it can also be expressed using discrete calculus

  • @mcdudelydoo3116
    @mcdudelydoo3116 2 года назад +4

    I gotta admit, this is one of my favorite videos of the SoME2 this year. This intrigued me so much and you explained it pretty straightforward even though I didn't completely understand everything on the first viewing. This year's SoME really gave us some banger math videos, can't wait for next year!

  • @funnydog7817
    @funnydog7817 2 года назад +22

    I’ve been shown another area of mathematics that peaks my interest, and has given me a decent view into the essence of it! Thank you, when it’s a drag it’s always better learning something new, and maybe finding some meaning within it.

    • @Tom-u8q
      @Tom-u8q 2 года назад +3

      Just in case you didn't know, it's "pique" in the phrase to "pique one's interest"

    • @lookupverazhou8599
      @lookupverazhou8599 2 года назад +1

      @@Tom-u8q Like Piqueachu.

  • @MultiAblee
    @MultiAblee 2 года назад +10

    Super interesting Stuff! I like how categorically you can see in this topic that calculus itself is a limit of this discrete version! The exposition was super easy to follow, love it.

  • @harelrubin1432
    @harelrubin1432 4 месяца назад +3

    I like that you mentioned the prerequisites at the start of the video, and I also liked that you didn't explain what a complex number is like an average math channel

    • @Supware
      @Supware  4 месяца назад +1

      Thanks! The ideas there were that #1 lets the audience know they're watching the right video (or not), and #2 complex numbers aren't particularly necessary but can be used if you're familiar with them :)

  • @SouthTC2
    @SouthTC2 10 дней назад

    your channel is a Godsend, you're welcoming me into the abstract and lovely world past what most people learn in their lives, you are so helpful, please don't stop making videos on forms of mathematics not usually talked about! You are gonna blow up bro, keep it up!

    • @Supware
      @Supware  10 дней назад +1

      Thanks so much man! I have been a little distracted by other projects and IRL stuff, but I do already have another video in the works that I'll get back to soon enough (conics and elliptics) :)

    • @SouthTC2
      @SouthTC2 10 дней назад

      @@Supware Can't wait! I've been pretty busy so I can't wait to finish this video soon, same with your other one, I have both in my watch later playlist, so far I really like what you have, please continue making God blessed content :D, ppl need more math in our lives

  • @miklosbognar1449
    @miklosbognar1449 2 года назад +3

    this is probably one of my favorite math videos on youtube, well done

  • @rosettaroberts8053
    @rosettaroberts8053 2 года назад +11

    Oh wow, this is really cool! I've played around with the umbral operator before without realizing what it was. I think the most recent time I used it is when I was converting a formula for factorial moments into a formula for non-central moments a few weeks ago.

    • @Supware
      @Supware  2 года назад

      Oh nice! I'd love to know if it has a name or symbol, I somehow haven't come across either yet

  • @therealjordiano
    @therealjordiano 2 года назад +2

    The part at 7:35 when you introduced the main idea I near enough leapt out of my chair and yelled 'holy shit!' from the bottom of my lungs (not rly but still), amazing stuff and very nice explanation

  • @MirMarksman
    @MirMarksman 2 года назад +28

    Rad! The familiar-but-different feeling makes this feel almost like a math dream

    • @Supware
      @Supware  2 года назад +1

      After working for a while on a second video I think this might actually be a major vibe I wanna aim for haha

    • @alpers.2123
      @alpers.2123 2 года назад

      Is this similarities related to group theorem?

    • @Supware
      @Supware  2 года назад +4

      @@alpers.2123 phi is a homomorphism between discrete and classical calc

  • @LebronJ0
    @LebronJ0 2 года назад +1

    What a legend only one ad in the beginning . Your so damn underrated

  • @qazxwecvr
    @qazxwecvr 2 года назад +3

    Did anyone else get excited at 7:42 when they realized that he's drawing a commutative diagram? (with elements of the objects instead of the objects themselves, but still)

    • @Supware
      @Supware  2 года назад +3

      More coming! I got some bad bois in the follow-up whose objects aren't even labelled ;)

  • @vnever9078
    @vnever9078 2 года назад +2

    Thank you Supware for introducing me to this beautiful world of Umbral Calculus!

  • @mbdtsmo
    @mbdtsmo 14 дней назад

    Great video, crystal clear. Had never heard of umbra calculus before, but recently read about umbral/monstrous moonshine, so I was curious. Thanks

  • @jmcsquared18
    @jmcsquared18 7 месяцев назад +1

    That was one of the most entertaining things I've ever watched. Bravo, subscribed.

    • @Supware
      @Supware  7 месяцев назад +1

      Wow, thank you!

  • @Fysiker
    @Fysiker 3 месяца назад

    I've loved what I've seen of the video, I love calclulus, but I think I've fallen asleep both times I've tried to watch this, something about your voice and the pauses to think/read tell my body to sleep. I will return, you can look forward to the difference created by the sum of my discrete efforts to finish this delightful presentation.

  • @GalHorowitz
    @GalHorowitz 2 года назад +8

    At 13:40, why is there a phi before D^n? isn't (D^n f(0)) just a constant?

  • @firefox7857
    @firefox7857 2 года назад +6

    3:01
    I've never seen that explanation for the fundamental theorem of calculus... it seems so simple now.

    • @angelmendez-rivera351
      @angelmendez-rivera351 2 года назад +3

      Well, unfortunately, the equation shown on screen is not actually what the fundamental theorem of calculus is or says.

  • @dcterr1
    @dcterr1 2 года назад +2

    Wow, this is fascinating! I never learned much about discrete calculus before, but you've definitely whetted my appetite! Great job!

  • @whitestonejazz
    @whitestonejazz 2 года назад

    this video was a trip. crazy to think this was never mentioned in any calculus classes. Very cool, thanks!

  • @willcollings5681
    @willcollings5681 17 дней назад

    Just want to say thank you. I'm working on translations between the Laplace transform and the Z transform (it's discrete counterpart) and this definitely sheds some extra light on the topic

  • @EC-pf1tr
    @EC-pf1tr 2 года назад

    This was awesome. I feel like I finally have a window into why I leaned everything that I did and how everything is connected from combinatorics to sums and differences and the discrete, to the continuous, to linear algebra, to complex numbers

  • @MCLooyverse
    @MCLooyverse 2 года назад +1

    Absolutely wonderful. Something about conjugation (q * x * q^(-1)) makes me happy every time it comes up (it comes up a lot).

  • @joshuaiosevich3727
    @joshuaiosevich3727 9 дней назад

    Man, this stuff is really my wheelhouse, I messed around with umbral calculus a lot in high school and early in college. Here’s some fun stuff I noticed.
    First thing I found was a formula for the n-th difference of a sequence, and then a formula to recover a sequence from those differences. What was striking, is that the “sum” of a sequence depended on the same difference coefficients as the original sequence. Meaning that if a sequences differences terminate, or obey a discernible pattern, computing a closed form for its summation is trivial.
    This lead me to a “better” version of fahlbauers formula that also works for any polynomial.
    Another fun thing I noticed is that this umbral calculus lets you count permutations that fix different numbers of elements. Take the group Sn, and let P(k,n) denote the number of permutations in Sn that fix k elements. Summing over all k gives you the size of the group which is n! . Note the P(k,n) can also be written as (n choose k)P(0,n-k), there are (n choose k) to pick the elements you fix, and those that remain, are not fixed at all. At this point in the argument, if you know umbral calculus, you’re all done! You see that P(0,n-k) is the k-th difference of n! ! Once you figure out permutations that fix 0, you get all the other ones too.
    This all amounts to a curiosity though, not good for much.

  • @luiz00estilo
    @luiz00estilo 2 года назад +1

    Just leaving a comment to help with the algorithm. This video was _enlightening_ . Great work man!

    • @arongil
      @arongil 2 года назад +1

      Agreed, the algorithm needs to know this video is top quality! Leaving this comment for the same reason :)

  • @GelidGanef
    @GelidGanef 2 года назад

    This hit the sweet spot for me in that it's perfectly intuitive that this should work, but how it works and why blows my mind.

  • @proxagonal5954
    @proxagonal5954 2 года назад +68

    Very high quality vid! I once read the Wikipedia page on discrete calculus, and the conclusion I came up with after reading for a bit was that it was dumb people calculus for dumb babies, and also that it was boring and dumb. But this was actually pretty interesting!
    The video & graphics quality here was great, loved the visualizations and I would've loved it if you had even more graphing and illustrations, especially in the later parts of the video. I'm looking forward to your next video!!

    • @Supware
      @Supware  2 года назад +5

      Thanks! Illustrations are certainly gonna be an interesting challenge in the next one...

    • @Briekout
      @Briekout 2 года назад

      @@Supware what are you demonstrating with sir? MathCad ?

    • @Supware
      @Supware  2 года назад +5

      @@Briekout Manim

    • @alpers.2123
      @alpers.2123 2 года назад

      It is calculus for engineers lol

    • @proxagonal5954
      @proxagonal5954 2 года назад

      @@alpers.2123 Don't laugh at engineers man. They cool

  • @utof
    @utof 3 месяца назад

    13:23 this is my favorite part. Makes me so excited to learn and explore this branch of math!

    • @Supware
      @Supware  3 месяца назад +1

      The bottom one amounts to a logarithmic spiral being the "ϕ of a circle", and as far as I know we're still figuring out the top one (for which the equation is incorrect but still interesting :p)! Both courtesy of the guys in the Discord

    • @utof
      @utof 3 месяца назад

      @@Supware woahhh awesome thank youu!!!

  • @SirTravelMuffin
    @SirTravelMuffin 2 года назад +1

    Really solid pacing, and definitely leaves me with a lot of curiosity for the subject!

  • @riccardofiori828
    @riccardofiori828 2 года назад +1

    This is one of the best math videos i've ever seen! Ideas are presented so neatly and however so mind-blowing. You earn a subscriber, I'm hoping for more videos like this!

  • @simonflavioibanez7715
    @simonflavioibanez7715 2 года назад +4

    Just…wow. Super concise, accurate, insightful, intuitively explained… definitely a video worth seeing by every modern mathematician. I’ll certainly look a little deeper on umbral calculus research thanks to you. My dearest congratulations. Thanks for sharing! 🧮

    • @Supware
      @Supware  2 года назад +1

      What a wonderful thing to read! Thank you so much!

  • @Malk007
    @Malk007 7 месяцев назад

    This video changed my (math) life. I can't think of anything else anymore.Thanks

  • @КириллБезручко-ь6э
    @КириллБезручко-ь6э 9 месяцев назад +1

    I don't understand what's happening at 13:30. Firstly, D^n f(0) is essentially a constant, and the operator phi cannot act on it. And if it can, then phi is not multiplicative, and therefore it cannot act on both x^n and D^n f(0). The final answer is correct, of course, but the approach is very strange

  • @okoyoso
    @okoyoso Год назад

    Out of all of the videos from SOME2, this one was the most eye-opening. Looking forward to SOME3!

  • @Aditya_196
    @Aditya_196 4 месяца назад +1

    😵‍💫 i am getting it but its moving so fast we need more deeper videos on this

  • @joda7697
    @joda7697 Год назад +1

    Umbral Calculus is just the best when you're deep in some special functions, like Bessel, Laguerre, and so on.

  • @maxime2949
    @maxime2949 2 года назад

    I don't usually comment on videos but such quality from a channel with 254 subscribers amazes me.
    This video's topic is really well chosen as it is understandable and complex and your explanations make it a great time !

    • @Supware
      @Supware  2 года назад

      Thanks, means a lot!

  • @kiiometric
    @kiiometric 2 года назад +1

    Oh my god my brain is tickling, this is beautiful

  • @kkski4817
    @kkski4817 2 года назад +1

    I like this video a lot

    • @Supware
      @Supware  2 года назад

      Hey thanks! I installed a de-esser for the next video, hopefully that'll do it :)

  • @PamSesheta
    @PamSesheta Год назад

    This has reminded me of something from a calculus class near the end.
    This was amazing, first encounter with phi operator and now I wanna know more because this seems really handy for dsp

  • @orirrr8
    @orirrr8 2 года назад +1

    Extremely clear, insightful and interesting exposition!

  • @NoNTr1v1aL
    @NoNTr1v1aL 2 года назад +1

    Absolutely amazing video! Subscribed.

  • @ficakcblack1090
    @ficakcblack1090 2 года назад

    This video is so amazing, it blew my mind, please continue making these

  • @diegohcsantos
    @diegohcsantos 2 года назад

    I really want to see more advanced discrete calculus stuuf!!! Thank you so much for the high quality video!!

    • @Supware
      @Supware  2 года назад

      I'm planning some shorter videos on summation by parts and summation using complex numbers :)

  • @madeline-capi
    @madeline-capi 2 года назад +1

    Great video about a topic I didn't really know anything about. Surprised of seeing stirling numbers too, when I learned about them they were shed by a completely different light and these kind of connections are what make math so interesting.
    Looking forward for a follow-up! And I hope this video gets blessed by the algorithm just like other SOME2 videos have been. Thanks and have a great day.

  • @HaliPuppeh
    @HaliPuppeh 2 года назад

    This was really interesting. Thank you for explaining things slow enough that I could keep up. So many videos on advanced topics go too fast and I get really lost.

  • @theseusswore
    @theseusswore 2 года назад

    3b1b's manim is an incredible tool for stuff like this. calculus and its practicality go hand in hand, so being able to visualise stuff in calculus is incredibly important to understanding it

    • @Supware
      @Supware  2 года назад

      It's such a great tool! Even for simple things like manipulating equations, it makes everything so much faster and easier to follow
      If I were using paper or a whiteboard instead this video would be 2 or 3 times as long for sure

  • @jaafars.mahdawi6911
    @jaafars.mahdawi6911 Год назад

    Simply fabulous! More of these, please, sir!

  • @akio-the-lazzycatto
    @akio-the-lazzycatto Год назад

    Wow, that is pne of THE BEST videos I've seen! I am impressed! This is magic in real life!

  • @georgecote
    @georgecote 2 года назад

    awesome quality! I'll be very happy to see more of that :) good luck!!

  • @tricanico
    @tricanico 2 года назад +2

    Wow, that was so cool. Thanks for posting this.

  • @KoHaN7
    @KoHaN7 2 года назад

    This was an incredible video. The way in which you merged everything together was mesmerising! I can't wait to se the follow up and some more exceptional quality of work and educational content. Bravo!

  • @netcat22
    @netcat22 2 года назад

    This was beautiful, I had never heard of this branch of calculus before but I'm absolutely in love with it. Your sub count honestly shocked me, this was such high quality.

  • @Celastrous
    @Celastrous 2 года назад +1

    Please keep making these!!

  • @ILSCDF
    @ILSCDF 2 года назад +2

    Wow, i definitly want more of this

  • @drbuckley1
    @drbuckley1 2 года назад

    I'm not a mathematician, so the algebra was tough, but the images were intuitive and very helpful. I understand the concepts even if I can't do the math. I'll definitely subscribe.

    • @Supware
      @Supware  2 года назад +1

      Hmmmm... that sounds like something a mathematician would say ;)

  • @djamondaxuzm4712
    @djamondaxuzm4712 2 года назад

    Thank you for the intro, really professional and keeps everyone on the same page

  • @alejrandom6592
    @alejrandom6592 2 года назад

    I can't believe you only have 321 subscribers, you deserve like a ton more

    • @Supware
      @Supware  2 года назад +1

      Hah thanks man! Guess I need to make more of these :p

    • @tomkerruish2982
      @tomkerruish2982 2 года назад

      One day later, it's 583 (including me now).

  • @kuppersrocky6834
    @kuppersrocky6834 2 года назад +1

    wow, great video, thanks!!

  • @randomz5890
    @randomz5890 2 года назад

    Amazing work here. Grant will definitely take notice to this! I generally love videos explaining more niche areas of maths, so I unfortunately have to be a bit selfish here and ask that you keep making more videos like this because they're amazing!

    • @Supware
      @Supware  2 года назад

      Working on it!

    • @randomz5890
      @randomz5890 2 года назад

      @@Supware awesome, I should expect you to be two steps ahead 😄!

  • @timkohl9831
    @timkohl9831 2 года назад

    This is something I've been curious about for a long time, thank you. This is very well made.

  • @paulkohl9267
    @paulkohl9267 2 года назад

    Loved it! Please, by all means, more on this topic.

  • @george_miller_1089
    @george_miller_1089 2 года назад +2

    Brilliant calculus video!

  • @robharwood3538
    @robharwood3538 2 года назад

    Great video! I had been exposed to Umbral Calculus a wee bit, but not much stuck with me; and I had also learned a little bit about doing finite sums (a la Newton) using falling and rising powers. But the two different parts of my brain didn't make the connection between the two topics until this video. Thanks!
    This new (for me) connection has already illuminated a lot of things I had been confused/stumped/stuck about before, and I can't wait to put this into practice!

  • @housamkak8005
    @housamkak8005 2 года назад

    PLEASE MAKE THIS INTO A SERIES

    • @Supware
      @Supware  2 года назад

      episode 2 coming soon :)

  • @pedroth3
    @pedroth3 10 месяцев назад

    Great explanation of this concept! Congrats and thank you

  • @jonipaliares5475
    @jonipaliares5475 2 года назад

    Really interesting topic and amazing explanation! I had never heard of Umbral Calculus up until now.
    I'm loving this summer of math exposition, I'm learning about so many new interesting things!

  • @SnapThority
    @SnapThority 2 года назад

    The maths animations are really good, I appreciate the effort you put into them!

    • @Supware
      @Supware  2 года назад +1

      Thanks, and sorry for only just noticing this comment haha! The animations were made possible by 3B1B's Python library. Great software but takes some setting up

  • @orktv4673
    @orktv4673 2 года назад

    The way that forward difference operator is defined strongly reminds me of Dirac's derivation of the gamma matrices.

  • @GeorgeTsiros
    @GeorgeTsiros 2 года назад

    i was intrigued by the thumbnail and the musterious/ominous-sounding title, not gonna lie

    • @GeorgeTsiros
      @GeorgeTsiros 2 года назад

      yeaaaah, i don't understand you :|

  • @pr4_kp
    @pr4_kp 2 года назад

    Incredible! I hope you do more on this topic - really got me thinking :)

  • @symbolspangaea
    @symbolspangaea 2 года назад +1

    This is a gem!

  • @kodirovsshik
    @kodirovsshik 2 года назад

    This was just WOW
    I always had the idea and the basics of the discrete calculus calmly sit somewhere in the back of my mind with me knowing that is it like "somewhat" related to the canon calculus, but now that i see this video, i realize that OH MAN is it something completely different!! I would surely love to see more content on some more advanced stuff on this topic, top interesting stuff

  • @ColeCoug
    @ColeCoug 2 года назад

    Great explanations and animations for a topic that I have never heard of before!! This video makes me want to learn more about it

  • @notjerrett
    @notjerrett 2 года назад

    Definitely looking forward to that followup!

  • @joseville
    @joseville 2 года назад

    10:37 interesting observation:
    The roots of the x^3+3x^2+x are
    (-3/2) +- (g -.5)
    Where g is the golden ratio (which is usually denoted as phi as well, but not this time to avoid confusion)

    • @Supware
      @Supware  2 года назад +2

      Fun fact: the golden ratio is gonna feature in the follow up video too! I was thinking about using the curly form of phi and painting it a golden colour... Maybe that's still not enough :p

  • @dyllanusher1379
    @dyllanusher1379 2 года назад

    Definitely looking forward to another video, thank you for sharing these mind blowing ideas!

  • @striga314
    @striga314 2 года назад +1

    This is so cooool. Which books or other texts could you recommend about this topic?

  • @sharpshark1158
    @sharpshark1158 9 дней назад

    In a sense the function with continuous steps whose rate of change is 1/x is ln(x), whilst the function with discrete steps whose rate of change is 1/x is H(x). By H(x) I mean the function that returns the x-th number of the harmonic series. For example: (ln(x) - ln(x - h))/h = 1 / x if h is infinitesimal, but (H(x) - H(x - h))/h = 1 / x if h is 1!
    I think this really displays well why the phi of ln(x) (phi basically transforming a function from continuous calculus into its umbral calculus version) would be the harmonic series.

  • @4aasdaw
    @4aasdaw 9 месяцев назад

    The diagram at 7:45 looks suspiciously like the commuting diagram for a naturality square where phi is the natural transformation between two functors. This is why you can't 'divide by phi', phi is actually a family of arrows with components at each continuous function up top.
    I'd wager the two functors are the ones that map onto 'continuous' and 'discrete' functions, though I'm not sure from which category they'd map from; that much is far above my head.

    • @Supware
      @Supware  9 месяцев назад

      Not sure what you mean by "can't 'divide by phi'"...? But I also know next to nothing about categories and functors heh

    • @4aasdaw
      @4aasdaw 9 месяцев назад

      @@Supware in phi D = Delta phi, you can't get D = Delta by 'dividing' both sides by phi :)
      Non-commutativity of operators is the default assumption if you look at them as arrows like this, since function composition isn't commutative either.

  • @danieljulian4676
    @danieljulian4676 2 года назад +2

    I already had a quick introduction to discrete calculus. This is wonderful next step. I see someone else already compared your approach to Grant's. So generous and clear, both of you.

  • @diogeneslaertius3365
    @diogeneslaertius3365 2 года назад +1

    9:03 I see what you did there: n_2 = n(n-1) = n^2 - n, n = n_1, n^2 = n_2 + n_1 and then phi inverse (n^2) = phi inverse (n_2 + n_1) = n^2 + n.
    Why didn't you explain this part? When I saw it for the first time I got confused a bit.
    UPD: I saw you are actually explaining it right after this example :).

  • @michelangelowebb4362
    @michelangelowebb4362 2 года назад

    I hope you continue with this videos. It it amazing work. Thanky you man !

  • @eduardoabreu78
    @eduardoabreu78 2 года назад

    Fantastic, you Sir did a Great Work!

  • @wdobni
    @wdobni Год назад

    this umbral calculus is the quantum mechanics of mathematics where the wave function is applied to the derivative of the delta operator and the result is a function amplitude which, if squared, gives you the probability that you have the correct answer in terms of the sigma of the exponential.

  • @mitch9224
    @mitch9224 20 дней назад

    Incredible work - this has to be one of my favourite math videos. It really does leave you wanting to learn more about the subject which is such a good feeling. Fabulously presented as well :)
    My only question is concerning how at the end you mention that the two series are the same up to an isomorphism. What exactly is meant by this?

    • @Supware
      @Supware  20 дней назад +1

      Wow, thank you!
      By "isomorphic" here I just meant that one is a direct analogue of the other: the underlying structure of what's going on is the same, but in one case we're in the differentiation world and in the other we're in the differences world

  • @minimath5882
    @minimath5882 2 года назад

    This was great, I look forward to seeing more in the future!

  • @gianpierocea
    @gianpierocea 2 года назад

    Incredibly well done, this is exactly my kind of thing. Thank you :)!