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Topology is weird: The Ham Sandwich Theorem

Dr. Trefor Bazett 47,018 lượt xem 2 years ago
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Today we talk about my favourite math theorem: the Ham Sandwich theorem. Consider a sandwich with three components. Then the theorem claims there exists some plane in three dimensions, where if I slice along that plane then I cut all three components exactly in half. We will see repeated use of the Intermediate Value Theorem in the simpler cases (which we call the pancake theorem), and then the more powerful Borsuk-Ulam theorem to prove the main result.

0:00 The Ham Sandwich Theorem
0:56 One Pancake and the Intermediate Value Theorem
2:12 The two pancakes theorem
3:40 Borsuk-Ulam Theorem
6:07 Proving the Ham Sandwich Theorem
10:45 Higher dimensions
11:24 Brilliant.org/TreforBazett

My previous video proving Sperner's Lemma and Brouwer's Fixed Point theorem (which can be shown are equivalent to Borsuk-Ulam): https://www.youtube.com/watch?v=oX9aPNF6_h8

I also have a previous video on Borsuk-Ulam and some other cool corollaries. It was actually my 10k subs video!: https://www.youtube.com/watch?v=z75B8iP1Y3g

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OTHER PLAYLISTS:
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►Cool Math Series:
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