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Knot Theory 6: The Knot Group 

Math at Andrews University
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Problem Set: drive.google.com/file/d/1MMTL...
Knot Theory: Lecture 6. Continuing the discussion of the fundamental group, calculating fundamental group of several spaces, including the complement of knots and links. Concludes with some mathematical magic tricks!
Andrews University: Math 487 (Spring, 2019)
Andrews Math Department: www.andrews.edu/cas/math/
Anthony Bosman: www.anthonybosman.com/

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19 фев 2019

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Комментарии : 25   
@RiccardoVincelli
@RiccardoVincelli 4 года назад
This course is a top-grade one! Taught with rigor, enthusiasm and passion. Especially on a set of topics rarely touched in mainstream math. Chapeau,
@xiaolonghanshan1755
@xiaolonghanshan1755 4 года назад
Seeing how Anthony play with his toys to demonstrate the subtlety of a simple change to unknot the Borromean rings is very exciting and inspiring. If there were more teachers like him in the class there will be less suffering for math students
@coldsoup49
@coldsoup49 5 лет назад
Thank you very much for posting these lectures!
@KUCaldog187
@KUCaldog187 10 месяцев назад
I'd imagine the creator(s) of this universe are masters at knot theory
@omargaber3122
@omargaber3122 6 месяцев назад
Amazing and you made it very easy , thank you very much ❤❤❤
@wdacademia2329
@wdacademia2329 11 месяцев назад
A natural question to ask is if two knots are equivalent iff their complements (as subspaces of ℝ³) are homeomorphic. The ⟹ direction is easy, but I suspect ⟸ is only true up to knot mirroring (unless we consider more structure on the subspaces). Edit: My suspicion is correct for tame knots (e.g. smooth knots or knots with a diagram with finite number of crossings). See the Gordon-Luecke theorem.
@elijahberegovsky8957
@elijahberegovsky8957 3 года назад
This is a wonderful course, thank you for making it! Question: is there a way to construct a knot with a given group in a Wirtinger presentation?
@meiliyinhua7486
@meiliyinhua7486 9 месяцев назад
my brain needed to catch up a bit away from normal homotopy and realizing the base point had to be fixed, since it kept being like "but aren't x, y, and z all homotopic loops?"
@cherish_till_you_get_perish
@cherish_till_you_get_perish 11 месяцев назад
We have came through knot theory
@AlabasterClay
@AlabasterClay 5 лет назад
This was a fabulous lecture....complete with a magic trick at the end. Only suggestion.....you sometimes mention names that are hard to spell just from hearing them. (like the special linked three rings) It would be helpful if you would spell these special names on the board.
@MathatAndrews
@MathatAndrews 5 лет назад
Thanks for the generous feedback! They're called the "Borromean rings" and are an example of a Brunnian link which is a link where removing any one component frees the other ones. I'll try to get better at writing such names on the board (assuming I myself know how to spell them!).
@user-ui9fs5ik3u
@user-ui9fs5ik3u 29 дней назад
Dear professor Anthony Bosman, I'm a highchool student in Korea. At first, thank you for the enthusiastic video. I was really impressed by the high quality and the content of the lecture. I've already knew the concepts of fundamental group and knot theory, but I've never thought of combining both up! And also the physical visualization of abelian and non-abelian fundamental groups were intriguing. In fact, I'm trying to operate a math experience booth in the school festival, so if it's okay, can I use your instance for the experience booth?
@MathatAndrews
@MathatAndrews 29 дней назад
Happily!
@annawahlbeck1689
@annawahlbeck1689 4 года назад
Thank you for these great movies! I´m preparing a lesson for my students about knot theory, and I would like to know where you have bought these string that you illustrates the knots with? Kindest regards, teachter from Sweden.
@MathatAndrews
@MathatAndrews 4 года назад
Thank you for the generous comment! And how exciting that you will be teaching a knot theory lesson! In this video, I use glow sticks! They are easy to clasp together and break apart. In particular, the glow stick necklaces tend to be long enough to make for good visual aids. And, you should be able to get quite a few for pretty cheap.
@annawahlbeck1689
@annawahlbeck1689 4 года назад
@@MathatAndrews Thank you for your answer! I have been searching at several toy websites and now, thanks to you, I know what to look for :) Ps, I'm writing my bachelor's thesis right know, where I examine the relationship between invariants of Fox n-coloring och the knot group. Your videos are very helpful in my work, you are a very good didactics! I want to thank you sincerely.
@MathatAndrews
@MathatAndrews 4 года назад
Best wishes on your thesis! That is very exciting!
@adityakhanna113
@adityakhanna113 3 года назад
22:45 For a deformation retract, does the map need to be the identity? Could it instead be any homomorphism of X?
@Bbdu75yg
@Bbdu75yg 7 месяцев назад
Wow❤
@samtux762
@samtux762 11 месяцев назад
What if I have a plane with two pocked holes. Is it ZxZ? Doesn't seem like it because the winding doesn't have a*b = b*a property.
@meiliyinhua7486
@meiliyinhua7486 9 месяцев назад
I would expect it to also be the free group of rank 2
@mathbiosis01
@mathbiosis01 8 месяцев назад
How might you explain to a lay person why gluing the edges of a rectangular sheet of paper to form a torus is permissible? When the "rules" of topology are first given, we say you cannot cut a space and re-glue its components in some odd fashion, because the relative position of points now get changed. But with a rectangular sheet of paper folded to make a torus, separate points on opposing edges end up fusing together, thus altering the relative position of these points. Do we simply tell a lay person that this is permissible to create a new space, whereas the "don't-cut-and-re-glue rule" is meant to preserve a space?
@marwaassem1087
@marwaassem1087 5 лет назад
Can you speak about Van Kampen theorem please?
@Iq187videos
@Iq187videos 4 года назад
fuzzy math
@kajamix
@kajamix 11 месяцев назад
Never happened. The Japanese were gunned down by British gunboats and then there were two or three crocodiles who ate a few of the dead bodies.
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