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| Photo: Evelyn Lamb |
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In the most recent episode of our podcast My Favorite Theorem, Kevin Knudson and I talked with aBa Mbirika (who goes by aBa), a math professor at the University of Wisconsin Eau Claire. You can listen to the episode here or at kpknudson.com, where there is also a transcript.
If you'd like to see aBa's talk from the Joint Mathematics Meetings, which he mentioned in the episode, it was recorded, and you can watch it here.
As is the case for many of our guests, aBa had trouble choosing a favorite theorem. He took us on a tour of a few of his favorites before settling on one to tell us more about. The theorem he settled on is not an important theorem. You won’t find it in any textbooks. But it was important to aBa when he was a beginning math student.
Many people are familiar with divisibility tests for 3 and 9: if the (base ten) digits of a number add up to a multiple of 3, the number is divisible by 3. If they add up to a multiple of 9, the number is a multiple of 9. There are also easy ways to tell whether a number is divisible by 2 or 5 or 11. But you probably didn’t learn a divisibility test for 7. (There is one, but it’s not as easy to use as the rules for 3 and 9.)...
I suspect many other mathematicians have similar stories of the simple, often unimpressive theorems and exercises that first made them feel like they had the power to create in mathematics. I certainly felt this way in my very first proof writing class. So today I salute the tiny theorems that helped us become mathematicians.
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Source: Scientific American
