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Counting Tilings (with Linear Algebra)
What does a chessboard have to do with trigonometry, complex numbers and linear algebra?
Well, quite a lot if you want to calculate the number of possibilities to tile said board with two by one tiles!
In this video, we will apply methods from seemingly unrelated fields to arrive at one of the most beautiful results in combinatorics, Kasteleyn's formula.
This video has been produced as part of the #SoME2.
0:00 Introduction
3:04 First Observations
8:56 The Signing
17:07 Linear Algebra Ahead
18:52 Final Sprint
25:59 Holes and Circles
Writing and Animation: Michael Zheng and Levin Kiefer
Narration: Michael Zheng
Editing: Levin Kiefer
Music by glaciære/Stevia Sphere: steviasphere.bandcamp.com/
(licensed under CC BY 3.0)
Tracklist:
Part 0: Bittersweet (Two Months of Moments)
Part 1: Mitosis (Music For Slime Creatures)
Part 2: Synth Gunk (Music For Slime Creatures) & Going to bed on a warm summer night (water slide)
Part 3: Relaxing in the hammock (hammock)
Part 4: Polar bears (hammock) & New Age Website (Reality is not a computer simulation)
Part 5: Ocean waves and Square waves (pool water blue)
Idea: Jiří Matoušek (2010), Thirty-three Miniatures - Mathematical and Algorithmic Applications of Linear Algebra.
Secondary sources:
Andries E. Brouwer, Willem H. Haemers (2012), Spectra of Graphs
Richard Kenyon (2008), An Introduction to the Dimer Model
Linyuan Lu (2009), Spectral Graph Theory - Handout 3: people.math.sc.edu/lu/teaching/2009spring_778S/adjeig.pdf
Image sources:
umdphysics.umd.edu/images/igallery/resized/1101-1200/Fisher_2-1110-1280-720-100.jpg
academictree.org/photo/057/cache.569571.Pieter_Kasteleyn.jpg
www.stfaiths.co.uk/wp-content/uploads/2017/05/Neville-Temperley-e1494584970554-1439x575.jpg
For a video that introduces a method to count the number of matchings for a larger class of graphs, see:
ua-cam.com/video/Y-gDWLQFE4g/v-deo.html
If, on the other hand, you are more fascinated by the Arctic Circle Phenomenon (or want to find the source of the "necklace figure"), see:
ua-cam.com/video/Yy7Q8IWNfHM/v-deo.html
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КОМЕНТАРІ

  • @dominus_ignaviae
    @dominus_ignaviae 2 місяці тому

    thank you so much! thing make a lot of sense now!

  • @vcubingx
    @vcubingx 11 місяців тому

    Just saw this - amazing video! Nice work :)

  • @edvogel56
    @edvogel56 Рік тому

    Thank you for addressing "how do you know you are done?" right at the beginning!

  • @abdomsisn
    @abdomsisn 2 роки тому

    14:44 I didn't get this part, in the example there are 11 red and blue outside edges so the product of weights will be -i and 1 and how does them differ by (-1)^16 = 1?

  • @Dragoo417
    @Dragoo417 2 роки тому

    Nice work ! I did a project on this during my bachelor (mainly explaining the same things you did, but with less visuals). One of the things you did not present was that the eigenvalues of the line graphs are actually (almost) the roots of Tchebyshev polynomials of the second kind. This avoids some calculations in the second half of the video but requires to know those polynomials in the first place. Anyway, thanks for your work !

  • @johnchessant3012
    @johnchessant3012 2 роки тому

    Great video!

  • @nikolakosanovic9931
    @nikolakosanovic9931 2 роки тому

    Please make background other color I think that my phone turned off every time

  • @masaftic
    @masaftic 2 роки тому

    amazing i like counting problems

  • @rubberduck2078
    @rubberduck2078 2 роки тому

    Nice voice

  • @WhiterockFTP
    @WhiterockFTP 2 роки тому

    amazing video!!!! keep it up

  • @adrien5568
    @adrien5568 2 роки тому

    I got lost in the middle. I find it funny because I was working with a kinda similar problem but with imperfect matching. I compute by hand the first values but those values are not in the OEIS, at this point I gave up.

  • @rajasvlog7729
    @rajasvlog7729 2 роки тому

    Aewsom

  • @rajasvlog7729
    @rajasvlog7729 2 роки тому

    More video is needed

  • @Number_Cruncher
    @Number_Cruncher 2 роки тому

    I got lost in the middle. But it sounds like a really fascinating calculation. I will definitely go through it one more time more carefully. It is really nicely presented. It's amazing what different pieces enter into the proof.

  • @felixwang4149
    @felixwang4149 2 роки тому

    Great Video. Easy to follow and nice style and animations.

  • @TheCustrOomer
    @TheCustrOomer 2 роки тому

    This is sumthing really awesum!