Splash at Northwestern: Winter Splash February 26th, 2023

# NU Splash Biography

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## ANDREW GENG, UChicago grad student studying geometry

College: University of Chicago

Major: Mathematics

## Brief Biographical Sketch:

An alumnus of MIT, Andrew is a believer in the power of science to enrich how people see the world--elucidating important questions such as: "Why don't rubber bands lie flat when wound twice around a rolled-up poster?" "Why can an A-440 tuning fork ring at a high F?" "What kinds of oils are good for frying?"

These days Andrew studies math at the University of Chicago, hoping that one day he'll understand the quirky behaviors of dimensions. In his leisure time he likes to write pretty music and draw pretty pictures.

## Past Classes

(Clicking a class title will bring you to the course's section of the corresponding course catalog)

M264: Idempotents: Forever Squared in Splash 2014 (Apr. 06, 2014)
$$6^2 = 3\boxed{6}$$ $$76^2 = 57\boxed{76}$$ $$376^2 = 141\boxed{376}$$ Can you find more numbers like this? Is there a limit to how long they can get? Can you find any which end in 5 instead? Can you do this in base 2? Base 12? In our quest to answer these questions, we'll take a little excursion through an area of math known as ring theory.

M265: String! in Splash 2014 (Apr. 06, 2014)
Can you untie a knot by tying another knot next to it and canceling them out the way you cancel opposites in math class? Can you hang a picture on two nails in a wall so that the picture falls down if a single nail--no matter which one--is removed? How could math possibly help with questions like these? And how could these possibly help with anything people actually do with string? String will be provided. Bring your own questions too!

A269: Write Your Own Silly Lyrics! in Splash 2014 (Apr. 06, 2014)
Have you ever wanted to write a song parody like Weird Al does? Of course you have! So bring in something to sing about, and let's make it happen! Along the way we'll pick up some tidbits about rhyme, meter, and singable words—which are of course applicable to more than just song parodies. Ability to sing is not required.

M278: Hyperspheres and Twisted Ribbons in Splash 2014 (Apr. 06, 2014)
Everybody learns to double a rubber band around a poster when it's too loose. But then you have this twist in the rubber band, and nobody ever tells you how to get that out. What if I told you that the rubber band's untwistability is determined by an arc on a sphere in 4D space? Does this shape even exist in the real world, and how does it control the twisting of ribbons and rubber bands? Ribbon, rubber bands, and pretty pictures will be provided. Bring your own questions! No geometry experience necessary!

M245: Idempotents: Forever Squared in Splash 2013 (Apr. 06, 2013)
$$6^2 = 36$$ $$76^2 = 5776$$ $$376^2 = 141376$$ Can you find more numbers like this? Is there a limit to how long they can get? Can you find any which end in 5 instead? Can you do this in base 2? Base 12? In our quest to answer these questions, we'll take a little excursion through an area of math known as ring theory.

M149: Random Awesome Maths in Splash 2012 (Mar. 31, 2012)
Are you random? What about awesome? Come learn about random awesome maths! We might talk about about infinity, how to win games, weird shapes that are "between dimensions" and more! Bring your own questions or just come with an open mind.

M177: The Curiously Colorful Complex Plane in Splash 2012 (Mar. 31, 2012)
The complex plane has a real axis and an imaginary axis. So graphing complex functions $$w = f(z)$$ is easy! Start by drawing an axis for the real part of $$z$$, a second axis for the imaginary part of $$z$$, a third axis for the real part of $$w$$, and a fourth--wait, what do you mean we only have room for three axes? Fortunately, we're still okay. Mathematicians have come up with ways to visualize these graphs by using colors. You might be surprised by what we can say about the shapes of these graphs, based just on these two-dimensional color pictures!