About

About Me

Hi, my name is Yannick. Welcome to my blog! I'm interested in data science, math, and foreign languages, and those are the things I plan to write about.

A little background: I studied mathematics at Reed College and later at the University of Washington, where I worked on problems classical Iwasawa theory. Here are my graduate thesis and (what's more fun) my mathematical genealogy. After graduate school, I did a data science internship at Health Catalyst where I worked on healthcare.ai, an open source machine learning package for health care applications.

Birds and Frogs

Salientia is a group of amphibians including frogs and toads. The name of the blog is inspired by Freeman Dyson's AMS Einstein Lecture entitled Birds and Frogs in which he classifies mathematicians into two groups — birds and frogs — described as follows:

"Some mathematicians are birds, others are frogs. Birds fly high in the air and survey broad vistas of mathematics out to the far horizon. They delight in concepts that unify our thinking and bring together diverse problems from different parts of the landscape. Frogs live in the mud below and see only the flowers that grow nearby. They delight in the details of particular objects, and they solve problems one at a time. [...] The main theme of my talk tonight is this. Mathematics need both birds and frogs. Mathematics is rich and beautiful because birds give it broad visions and frogs give it intricate details. Mathematics is both great art and important science, because it combines generality of concepts with depth of structures. It is stupid to claim that birds are better than frogs because they see farther, or that frogs are better than birds because they see deeper. The world of mathematics is both broad and deep, and we need birds and frogs working together to explore it."

Dyson goes on to provide interesting examples of birds and frogs throughout the history of mathematics.

I was introduced to Birds and Frogs many years ago before I'd ever heard of data science. Even then, I recognized that I was not a bird, but I hope that there's at least a little bit of frog in me.

In that spirit, the purpose of this blog is to highlight some of the flowers I spot while hopping around in the mud of data science, languages, mathematics, and other interesting ponds.

Evolution of Birds and Frogs. These images were generated during training by a conditional GAN trained on CIFAR-10 by slightly modifying this tutorial. I don't feel that I understand either the theory or the Tensorflow code well enough to explain what's actually going on: when that changes, I'll probably write a blog post about it.

Word of the Week

I've always been interested in languages. I grew up in a bilingual household speaking both English and French and am currently trying to both learn a Russian-Ukrainian mishmash and Dutch. Featuring an interesting word each week seemed like a fun way to make some of my learning stick and also a helpful gimmick to encourage me to post regularly.

Limericks

The most dreaded part of my graduate experience were the required prelim exams. There were several core subjects for which you'd generally take a year long course, followed by a summer of reviewing exams from previous years, and culminating with a four-hour exam which could determine whether or not you were able to stay in the program.

One of the practice problems for the complex analysis prelim was something along the following lines:

Let \(f\) and \(g\) be two entire functions such that \(f\) and \(g\) have no zeros and \(f + g = 1\). Prove that \(f\) and \(g\) are constant.

When we went to present our solution, the professor smiled and said, "Oh, the limerick problem." Asked to elaborate, he explained that someone in the department had a solution to the problem that took the form of a limerick. Of course, we couldn't let such a challenge go unmet and spent an afternoon putting complex analysis to rhyme. We never learned what the original limerick proof was, but did come up with a solution:

To prove \(f\), \(g\) constant's not hard
For zero and one we discard
Since \(f\) plus \(g\)'s one
And zeros they've none
Hence we're finished: proof by Picard

This was a highlight of my prelim experience and reinforced the notion that, even in serious or stressful situations, one shouldn't take oneself too seriously. So if you find limericks sprinkled throught the blog, feel free to roll your eyes and ignore them:

I hope these poems do not deter
You may skip them if you so prefer
Yet this blog could be worse
Lacking prose, full of verse:
Written all in iambic pentameter