Cantor Intersection Theorem

Sdílet
Vložit
  • čas přidán 29. 08. 2024

Komentáře • 26

  • @ariel_haymarket
    @ariel_haymarket Před 3 lety +9

    "Press F to pay respects" good night everyone.

  • @rohitkandimalla9259
    @rohitkandimalla9259 Před 3 lety +5

    After watching one by one I addicted to your vedioes

  • @leprofeet9989
    @leprofeet9989 Před 2 lety +1

    yea that makes things clear

  • @FT029
    @FT029 Před 3 lety +2

    calling the subsequence the "express train" was pretty fun!

  • @umerfarooq4831
    @umerfarooq4831 Před 3 lety +2

    You have really helped me in every aspect of math

  • @lexyeevee
    @lexyeevee Před 3 lety +6

    you don't actually need the axiom of choice, do you? if the Fs are closed and bounded, then you can define a choice function, e.g. pick the minimum. in fact i'd think that makes the proof easier to grasp since then the sequence is nondecreasing

    • @drpeyam
      @drpeyam  Před 3 lety +2

      That’s true, good point

  • @dr.rahulgupta7573
    @dr.rahulgupta7573 Před 3 lety

    Excellent ! Beautiful presentation of the topic . Thanks .DrRahul Rohtak Haryana India

  • @psjt9230
    @psjt9230 Před 3 lety +1

    He is a great Mathematician

  • @dgrandlapinblanc
    @dgrandlapinblanc Před 2 lety

    Excellent ! Thank you very much.

  • @thedoublehelix5661
    @thedoublehelix5661 Před 3 lety +2

    This is sorta like the generalization to the nested interval property. Also, why do you use closed and bounded instead of compact ? Aren't they the same thing

    • @drpeyam
      @drpeyam  Před 3 lety

      Yeah but let’s keep it simple

    • @thedoublehelix5661
      @thedoublehelix5661 Před 3 lety

      @@drpeyam oh I guess you didn't prove that yet in the video series lol. I just thought it would be more elegant if you phrased things in terms of compact sets

    • @drpeyam
      @drpeyam  Před 3 lety +1

      Elegant yes, but quite traumatizing if you introduce it this way hahaha

  • @PositronQ
    @PositronQ Před 3 lety +1

    My favorite theorem, in which it has a property of incompleteness with several hypotheses as the proof of this is possible and at the same time not, the indeterminate independence is always there in all the problems defined with simple axioms in which they break and not. I think cantor do a good theorem that people underestimated. Also This theorem can give us a logic definition of the undefined everything is nothing. That is the same that I said in a “simple ways”.

  • @Akihikoo_
    @Akihikoo_ Před 3 lety

    Thanks so much Dr

  • @DELTASERPENT
    @DELTASERPENT Před 3 lety +1

    Great teaching Payamji. Need a bigger whiteboard

    • @drpeyam
      @drpeyam  Před 3 lety +1

      Buy me one then, haha

  • @madhavpr
    @madhavpr Před 3 lety

    Cool video.. One of my favorite theorems in analysis. Just a quick clarification- In single variable analysis, the point x that's contained in all the closed and bounded intervals F_n is *unique* if the lengths of these intervals goes to 0. I guess the same would be true for R^k { k >= 2} with an appropriate notion of "length". If the area/volume of closed and bounded sets (like generalized rectangles or hyper-spheres) goes to 0, then this point x is unique. Am I right?

    • @FT029
      @FT029 Před 3 lety

      I don't think this is right in one variable (oops- just realized you noted it was for intervals only, so this counterexample doesn't work). Consider F_n = [0, 1/n] union [1, 1 + 1/n]. The intersection of it all is just the points 0 and 1.
      I think, if you wanted to prove your claim, a connectedness argument might work. Maybe show that the intersection of all the sets is connected, and that the only connected set of measure 0 is just a singleton. (Although measure, defined in the usual way, wouldn't work because something like a line segment would have measure 0 in R^2)

  • @honghong324nt5
    @honghong324nt5 Před 4 lety

    For the first non-ex, wouldn't [0,1/n) also work even though it's not closed?

    • @drpeyam
      @drpeyam  Před 4 lety +3

      No since 0 is in all of them hence in their intersection

    • @honghong324nt5
      @honghong324nt5 Před 4 lety

      @@drpeyam Thank you!

  • @Happy_Abe
    @Happy_Abe Před 3 lety

    Funky