# ESP Biography

## GURBIR DHILLON, PhD student in math

Major: Mathematics

College/Employer: MIT

Year of Graduation: Not available.

## Brief Biographical Sketch:

Gurbir Dhillon grew up in California. After doing an undergraduate degree in math at Harvard, he found it enjoyable enough to want to keep at it. Accordingly, he currently is finishing a doctorate in math at Stanford, and has been at MIT as a visiting student for the past couple years.

## Past Classes

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

M13297: There are different sizes of infinity in Splash 2019 (Nov. 23 - 24, 2019)
You probably know that you have fewer hands than there are letters in the English alphabet. You also probably know that there are fewer letters in the English alphabet than there are whole numbers. But are there fewer' whole numbers than say, points on the number line between zero and one? Is it even well posed to ask whether one infinite collection of objects has fewer' constituents than another infinite collection of objects? We will walk through how one makes sense of such questions. By the end, we will see that there really are different sizes of infinity (in fact, infinitely many). A great feature of this story is that, aside from remembering what numbers are, you don't need prior background in math, and the style of reasoning is pretty different from what you meet in a normal high school math class. So, people who think they don't like math are especially encouraged to give it a go.