Poincare Conjecture and the weird world of topology | Jordan Ellenberg and Lex Fridman

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  • Опубликовано: 24 ноя 2024

Комментарии • 25

  • @yabut2200
    @yabut2200 3 года назад +19

    I love watching these
    I had an D- in Maths

  • @HomelessHomeowner617
    @HomelessHomeowner617 2 года назад +1

    We could be living on a 3d klein bottle, like a 2d mobious strip, the line segment people are ignorant to the higher dimension

  • @Skiddla
    @Skiddla Год назад

    15:15 sounds like the game hyperbolica

  • @yuelwar4426
    @yuelwar4426 3 года назад

    Dear Alex, will you interview Prof Velani, from France about this subject???

  • @stemblackswan3901
    @stemblackswan3901 3 года назад +1

    Yes

  • @KaliFissure
    @KaliFissure 5 месяцев назад

    Surface (cos(u/2)cos(v/2),cos(u/2)sin(v/2),sin(u)/2),u,0,2pi,v 0,4pi
    The radially symmetric minimal energy single sided closed surface.
    What I believe is the form of the manifold.
    The twistor form.
    Notice that 4pi, two full covers, are needed to complete the surface. One cover is matter the other antimatter. Two REGIONS of the same manifold. The "other side of the looking glass" by truly the other side of time.
    Neutron decay cosmology. 🖖

    • @fullfungo
      @fullfungo 2 месяца назад

      Another crackhead 😣

  • @devrimturker
    @devrimturker 3 года назад

    14:08 what is the relation between Real Projective Plane (RP3) and Special Unitary Group SU(2). As you mentioned belt trick works for both

    • @mcxzx
      @mcxzx 3 года назад +1

      SU(2) is homeomorphic to 3-sphere, any closed path on it is obviously able to shrink to a point: If you cut a hole on a 3-sphere that is not on the path(so it won't affect the path), it is homeomorphic to 3d real plane(R^3), and path on the plane can always shrink to a point. since the whole process on the plane does not interact with the point we cut off(which is at the boundary of the 3d plane), such process is applicable on 3-sphere.
      RP^3 just identifies the opposite point on the 3-sphere, which is homeomorphic to a solid 2d ball with opposite points on its boundary identified. You can try to use the belt trick, and it will work out that a path that connects 2 opposite points on the boundary(because we identified them, so the path is closed) cannot actually be deformed into a point(you got to keep it close). But a path moving along that path twice would able to shrink to a point.
      And such idea is called fundamental group(π1) of the space. In the above example, π1(3-sphere) is {0} trivial group, π1(RP^3) is Z2 group(2 elements cyclic group). Poincare conjecture claims that any 3d closed manifold(can be thought of as closed smooth 3d surface) that its π1 is the trivial group(any closed path is able to shrink into a point) is homeomorphic to 3-sphere.

  • @wallstreetoneil
    @wallstreetoneil 3 года назад

    If the circumference of the Earth was slightly smaller, yet still the same Mass, and the Earth was completely flat without atmospheric dispersion, then light would bend around the earth, from the effects of curved spacetime due to earth's mass, such that you would always see the back of your head.

  • @bell1095
    @bell1095 3 года назад +1

    Gravity restricts its own unique space. Einstein GR surfed the idea.

  • @deadlevelled2870
    @deadlevelled2870 3 года назад +3

    The Tao begot one. One begot two. Two begot three. And three begot the ten thousand things

    • @adamwoodie4029
      @adamwoodie4029 3 года назад +1

      If one begot two, then why did the two only beget three and not four?

    • @deadlevelled2870
      @deadlevelled2870 3 года назад +1

      @@adamwoodie4029 To be sure, 4 came shortly after 3 and so on subsequently.
      Although, It may have multiplied Itself each iteration so integers may have been a package deal functionally speaking.

    • @adamwoodie4029
      @adamwoodie4029 3 года назад +1

      @@deadlevelled2870 word. Would you agree, though, that this whole concept is ultimately built on the foundation of a presupposition that can't be proved without coming to a point of circularity?

    • @Bennytwoshitz
      @Bennytwoshitz Год назад

      Cock begot balls

  • @StephenAntKneeBk5
    @StephenAntKneeBk5 3 года назад +7

    His speech is so infected with junk words "sort of" and so on, it is difficult to understand what he's saying. When he says "sort of" does he mean actually? When he says "like" does he mean actually? Which words am I supposed to disregard? Primary junk words infecting far too much speech -- "Sort of, "like" and "you know" along with "I mean," "so," and "right"

    • @bouquet_of_circles4484
      @bouquet_of_circles4484 3 года назад +21

      It's because what he is saying is not 100% precise, you need to be a bit imprecise to explain abstract mathematical concepts to a general audience in an intuitive way. So when he says "sort of", it's him telling you that what he is saying is the rough idea without the rigor. I can assure you it would sound far worse if he used the actual technical jargon.

    • @mkfort
      @mkfort 3 года назад +9

      If it offends you feel free to learn the actual math instead of watching RUclips clips

    • @StephenAntKneeBk5
      @StephenAntKneeBk5 3 года назад

      @@mkfort You've missed the point completely. it has nothing to do with that. Why do automatically assume that? Anyway, never mind.

    • @mkfort
      @mkfort 3 года назад +10

      @@StephenAntKneeBk5 he literally discusses in the podcast the difficulty of talking about math versus talking math directly. He's trying to use as precise language as he can without deceiving. I'm a native English speaker and I think he's well spoken and enjoyable to hear, I'm sorry you disagree.

    • @gabrielherman8930
      @gabrielherman8930 Год назад

      Sounds like a you problem