In my modest opinion, Professor Emily Riehl is one of the most impressively bright minds at the top of theoretical/abstract Mathematics, especially higher Category theory. Her focus is homotopy type theory (HoTT), which is the study of continuous transformations of functions from one category (eg. the category of natural citizens ) to another category (eg. the category of Facebook accounts or the category of email addresses). What makes her work special is her inclination towards the practical, real-life applications and humanistic value, beyond utility. One particular topic I appreciate from her work on “applied category theory” is referring to the concept of for both categories and observers (witnesses) thereof.

And she plays the violin

A very good presentation from Quanta Magazine.

 
One of her most remarkable books is “Category Theory in Context“