What are...algebraic varieties?

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  • Опубликовано: 1 янв 2025

Комментарии • 23

  • @francescosorce5189
    @francescosorce5189 9 месяцев назад +4

    Little silly thing, on the first slide you forgot a square on the R for the circle equation.
    9:11 Funny story, just after having my geometry 1 exam (basically linear algebra) I ended up chatting a bit with my professor since I was the last person that day and while packing things up he just started to semi-jokingly list all the reasons why the complex numbers are so much better than the reals.

    • @VisualMath
      @VisualMath  9 месяцев назад +2

      Ah, didn't I say the R=1? No? Too bad 😨
      Anyway, thanks for spotting 😀 I have put a warning into the description.

  • @yash1152
    @yash1152 9 месяцев назад +2

    2:24 > _"algebraic geometry studies zero sets of polynomials"_
    i guess then, that it's different than Clifford's "geometric algebra" right??
    8:22 yeah, it's definitely different

    • @VisualMath
      @VisualMath  9 месяцев назад +4

      Exactly 👍. AG is quite different in spirit from geometric algebra. The latter wants to include “geometry” (mostly vectors and friends) into algebra, while AG tries to make geometry as algebraic as possible.

    • @yash1152
      @yash1152 9 месяцев назад +2

      @@VisualMath awesome note. thanks for sharing ur thoughts (:
      > _"latter wants to include “geometry” (mostly vectors and friends) into algebra, while AG tries to make geometry as algebraic as possible."_

    • @VisualMath
      @VisualMath  9 месяцев назад +1

      @@yash1152 Welcome 👍

  • @OrdenJust
    @OrdenJust 9 месяцев назад +3

    Nicely presented!

    • @VisualMath
      @VisualMath  9 месяцев назад +1

      Thanks for the feedback, that is very much appreciated ☺
      I hope you will enjoy the series.

  • @JoaoKogler
    @JoaoKogler 23 дня назад +1

    The way you've defined SL_n(K), as a set of particular matrices whose determinant is 1 led me to think that SL_n it's not in fact the variety, but actually the set of loci of zeroes of the determinants of these matrices is in fact the set of varieties , not SL_N(K) . Am I correct, or is there something I'm not seeing ? I'm not a mathematician, so it's important for me to get the precise idea....

    • @VisualMath
      @VisualMath  23 дня назад

      Ok, let me give it a shot; say for n=2 to have easier notation.
      Then SL2=all vectors [a,b,c,d] in C^4 with ac-bd-1=0. All that is done is to flatten the matrix [[a,b],[c,d]] into a vector and we think of the four possible entries as variables. The determinant = 1 condition is then a polynomial equation in four variables.
      I hope that helps!

    • @JoaoKogler
      @JoaoKogler 22 дня назад +1

      @@VisualMath Thanks for the answer, although it didn't addresed my question, maybe I didn't state it clearly. I understood that the determinant is a polynomial in the case, and that its zeroes constitute a variety. The point is that the zeroes of the determinant make a variety, not the SL(K). Unless the SL(K) is constitute by the zeroes of the determinant, but it's clearly the case. So, why to call SL(K) a variety ? I understood that a variety is the locus of the zeroes of a polynomial curve or surface.

    • @VisualMath
      @VisualMath  22 дня назад

      @@JoaoKogler Hmm, I think I answered your question. But maybe I misunderstood your question, so let me try again, say for SL2 😀
      SL2 = “matrices [[a,b],[c,d]] with ad-bc-1=0” = “points in K^4 vanishing for f(a,b,c,d)=ad-bc-1” = an affine variety
      That is why I would call SL2 an affine variety. Does this answer you question?

    • @JoaoKogler
      @JoaoKogler 21 день назад +1

      @@VisualMath Thanks, again. After watching your 4th lesson, on Idelas & Varieties, it occured to me now that maybe the locus of zeroes of the determinant of a particular SLK matrix form a variety, a geometric object, while SLK would be its algebraic counterpart, an ideal related to that variety. Well, I'm just guessing by now, I hope I'm not bothering with this.... Anyway, let me watch a bit more of your next lessons, maybe I should have not worry about the question for a while.

    • @VisualMath
      @VisualMath  21 день назад

      @@JoaoKogler If I can help you with anything, do not hesitate to ask!

  • @commonwombat-h6r
    @commonwombat-h6r 9 месяцев назад +2

    such a nice video! Thank you so much

    • @VisualMath
      @VisualMath  9 месяцев назад

      You are very welcome. I hope you will enjoy your journey through AG 😚

  • @Sidionian
    @Sidionian 9 месяцев назад +3

    Let's goooo brooo 🍾🍾🍾🤘🏼🤘🏼🤘🏼🙌🏼🙌🏼🙌🏼💪🏼💪🏼💪🏼🙏🏼🙏🏼🙏🏼🙏🏼

  • @TopeshMitter
    @TopeshMitter 4 месяца назад +1

    You are wrong !! Modern v2 of Algebraic Geometry doesnt constitute Grobner Basis , Homotopy Continuation . It is Derived Algebraic Geometry or Higher Algebraic Geometry,

    • @VisualMath
      @VisualMath  4 месяца назад

      Haha, or anything people like to call "modern" 🤣

  • @Sidionian
    @Sidionian 9 месяцев назад +1

    Those 14 minutes went by in a breeze.... Felt like 90 seconds.... 😢

    • @VisualMath
      @VisualMath  9 месяцев назад +1

      I hope that means the video was entertaining 😂

    • @Sidionian
      @Sidionian 9 месяцев назад +1

      @@VisualMath very much so... Perfect presentation... You're at 23k now... I'm guessing before you finish this series you will have surpassed 30k...possibly even 35k...Hopefully the RUclips algorithm does its thing 🙏🏼