"Data Ethics and Mathematicians"

Here is a new short article called "Data Ethics and Mathematicians"

(I wrote it for SIAM News only about 3.5 years after I promised them that I would write this article. 🤷🏻‍♂️)

"Ginzburg–Landau Functionals in the Large-Graph Limit"

Another of my papers has appeared in final form. Here are some details.

Title: Ginzburg–Landau Functionals in the Large-Graph Limit

Authors: Edith J. Zhang, James Scott, Qiang Du, and Mason A. Porter

Abstract: Ginzburg–Landau (GL) functionals on graphs, which are relaxations of graph-cut functionals on graphs, have yielded a variety of insights in image segmentation and graph clustering. In this paper, we study large-graph limits of GL functionals by taking a functional-analytic view of graphs as nonlocal kernels. For a graph W_n with n nodes, the corresponding graph GL functional GL_ϵ^{W_n} is an energy for functions on W_n. We minimize GL functionals on sequences of growing graphs that converge to functions called graphons. For such sequences of graphs, we show that the graph GL functional Γ-converges to a continuous and nonlocal functional that we call the graphon GL functional. We investigate the sharp-interface limits of the graph GL and graphon GL functionals, and we relate these limits to a nonlocal total-variation (TV) functional. We express the limiting GL functional in terms of Young measures and thereby obtain a probabilistic interpretation of the minimization problem in the large-graph limit. Finally, to develop intuition about graphon GL functionals, we determine the GL minimizer for several example families of graphons.

RIP Erik Bollt (1967–2025)

My collaborator Erik Bollt died suddenly and unexpectedly last Sunday (the 7th). Erik is a well-known applied mathematician, and he was especially in the applied dynamical-systems community. Erik and I wrote two papers together, including our paper on mathematically modeling cow synchronization.

You can read about Erik's research on his web page and his Google Scholar page.

There will be a memorial article at some point.

What Happens in Berkeley Stays in Berkeley (2025 Edition)

I am heading off to Berkeley for the Smale@95 conference, which is a short event in honor of Steve Smale's 95th birthday. It was very cool to be invited to it!

RIP Gary Lorden (1941–2023)

Gary Lorden, a profesor emeritus of mathematics at Caltech, died last night. In addition to being a mathematics professor, Gary held many leadership positions at Caltech. He was the only statistician in Caltech's math department, and I TAed for him during my junior year in the inaugural edition of the so-called "new core", which included major changes in Math 1 and Math 2. I got my gig as a consultant for the movie "Meet Dave" through Gary. He was also a very kind person.

Update (10/30/23): Caltech has posted a short obituary.

Nicolas Bourbaki and The Traveling Wilburys

Nicolas Bourbaki was basically the mathematics version of The Traveling Wilburys.

"Theorems" (to the tune of ' "Heroes" ', by David Bowie)

"Theorems" (to the tune of ' "Heroes" ', by David Bowie)

I, I will be pure
And you, you will use rigor
And nothing will take it away
We can show them, just for one day
We can prove theorems, just for one day

And you, you can have bounds
And I, I'll take infinite time
We're joint authors, and that is a fact
We're coauthors, and that is that
Mathematics'll keep us together
It will not be just for one day
We can prove theorems for ever and ever
What do you say?

I, I wish I could prove
Like my teachers, my teachers can prove
Though sometimes it's hard to keep it together
I can show them, for ever and ever
Oh I can prove Theorems, just for one day

I, I will be pure
And you, you will use rigor
And nothing will take it away
We can prove Theorems, just for one day
We can do it, just for one day

I, I can remember (I remember)
Standing, by the board (by the board)
Arguments, far above our heads (over our heads)
And we tried, and we were never ignored (never ignored)
Our mentors, were always on our side
Oh we can show them, for ever and ever
Then we could prove Theorems, just for one day

We can prove Theorems
We can prove Theorems
We can prove Theorems
Just for one day
We can prove Theorems

We're students, and nothing will help us
Maybe it's hopeless, then you better not stay
But we could graduate, maybe one day

Oh-oh-oh-ohh, oh-oh-oh-ohh, maybe one day?

"The Professional Road that I have Traveled (so far)"

I was asked to write about my career trajectory for DSWeb, so I wrote this short article, which officially has the generic title of "Professional Feature — Mason A. Porter".

I really like my concluding sentence: "I want my mentees to continue to do excellent mentorship and research, be warm and kind-hearted, and not take any crap from anyone."

RIP Abdul-Aziz Yakubu (1958–2022)

A couple of weeks ago, I heard the very sad and unexpected news that Abdul-Aziz Yakubu had died. Aziz was great.

Like others, I also have some Aziz stories (but the one that I wanted to tell seemed a bit too light-hearted to tell immediately on social media): I know Aziz from my days helping out with MTBI as a PhD student. On one occasion, when somebody — one of the students? — was being a bit formal with my name as I entered a room and was also using my last name or something, I made the mistake of loudly proclaiming "I'm like Madonna. I only need one name." With a quietly wicked sense of humor (and with the knowledge that we'd all be amused by this, including me), Aziz proceeded to jokingly call me "Mason Madonna" for the next several years.

You can read more about Aziz in his 2020 Mathematically Gifted & Black profile.

"Math Prof" (a parody of “Dentist” from Little Shop of Horrors)

“Math Prof”

(a parody of “Dentist” from Little Shop of Horrors)

[MATHEMATICS PROFESSOR]
When I was younger, just a small geeky kid,
My mama noticed nerdy things I did,
Like countin' all the lights in the ceilings
I'd find their patterns, and after these things
I'd create a small maze and see where it led
That's when my mama said

[POSTDOCS]
What did she say?

[MATHEMATICS PROFESSOR]
She said, "My boy, I think someday
You'll find a way
To make your natural tendencies pay
You'll be a math prof
You have a talent for countin’ things up
Son, be a math prof
People will pay you to be all stuck-up
Your temperament's wrong for the priesthood
And business would suit you still less
Son, be a math prof
You'll be a success

[POSTDOCS]
Here he is, folks, the leader of the proof!
Watch him be oh so aloof!
Oh, my god!
He's a math prof and he'll never ever be any good
Who wants a thesis defense with someone in that mood?

[STUDENT]
Oh that hurts! I don’t know!

[MATHEMATICS PROFESSOR]
Oh, shut up. Think faster. Now go!
I am your math prof

[STUDENT]
Goodness gracious!

[MATHEMATICS PROFESSOR]
And I enjoy the career that I picked

[POSTDOCS]
Really love it

[MATHEMATICS PROFESSOR]
I am your math prof

[STUDENT]
Proving theorems

[MATHEMATICS PROFESSOR]
And I get off on the pain I inflict

[POSTDOCS]
Really love it

[MATHEMATICS PROFESSOR]
I thrill when I ask a tough question

[POSTDOCS]
Tough question
[MATHEMATICS PROFESSOR]
It's swell though they tell me I'm maladjusted
And though it may cause my students distress,
Somewhere, somewhere in Heaven above me
I know, I know, that my mama's proud of me
Oh, mama
'Cause I'm a math prof and a success
Say pi!

[STUDENT]
Pi!

[MATHEMATICS PROFESSOR]
Say mu!

[STUDENT]
Mu!

[MATHEMATICS PROFESSOR]
Say nu!

[STUDENT]
Nu!

[MATHEMATICS PROFESSOR]
Now prove it!

My Current Mathematics Genealogy

Here is my current mathematics genealogy.

My current Mathematics Genealogy (with doctoral students only): https://t.co/EAOiY0tasi

My MGP page (24 doctoral students): https://t.co/p35XlLXjoA

Current doctoral students: Abby Hickok, Grace Li, Jerry Luo, Kaiyan Peng, Mina Shahi

Also: I can't wait to have grandstudents! pic.twitter.com/dOU2wviu1V

— Mason Porter (@masonporter) July 16, 2021

2021 Abel Prize: László Lovász and Avi Wigderson

The 2021 Abel Prize goes to to mathematician László Lovász and computer scientist Avi Wigderson "for their foundational contributions to theoretical computer science and discrete mathematics, and their leading role in shaping them into central fields of modern mathematics."

RIP Peter Neumann (1940–2020)

This morning, I saw the terrible news that my former Oxford colleague Peter Neumann died today, supposedly due to complications from COVID-19 (although I can't verify if that is the known cause of death). Here is is Peter's Wikipedia entry.

I had the chance to interact with Peter quite a few times at Oxford. When I knew him, he was concentrating on mathematics history, and I contacted him with a query about some mathematical linguistics (concerning, for example, the use of "topological" only versus both "geometric" and "geometrical"). I knew that Peter was the right person to approach when I wanted to dive deeper than what I was able to do via Google. Here is my 2013 blog entry about that.

Peter was one of the people in Oxford who was always so kind and supportive of me (and, from what I can tell, of many others as well). When I got some pointed negative teaching evaluations, Peter invited me to The Queen's College to dinner to chat about things (and to give gentle advice and so on). But if I am getting rewarded with a dinner like that for messing up, it does create strange incentives. My students in my courses now are certainly benefiting from advice Peter gave me over the years. He also supported me in various fights on committees (we were on Teaching Committee together) and particularly in efforts that I made against "We've always done it this way." comments to try to change things in Oxford's Mathematical Institute.

(Tip of the cap to Card Colm Mulcahy.)

2020 Nobel Prize in Physics

The 2020 Nobel Prize in Physics was announced today.

The first thing that I noticed was that my Mathematical Institute (Unversity of Oxford) colleague Roger Penrose got half the prize. Additionally, Andrea Ghez from UCLA's physics department shared the other half of the prize with Reinhard Genzel. Ghez also got a Ph.D. from Caltech in 1992, so several of my institutions (and my former home department at Oxford!) did very well today. Congratulations!

Here is the terse citation: 

The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics 2020 with one half to Roger Penrose "for the discovery that black hole formation is a robust prediction of the general theory of relativity" and and the other half jointly to Reinhard Genzel and Andrea Ghez "for the discovery of a supermassive compact object at the centre of our galaxy".

Some other websites to look at are the popular blurb and more advanced information from the Nobel page. Additionally, here are UCLA's press release and a blurb from University of Oxford's Mathematical Institute.

A Great Ph.D. Defense by Dr. Will Oakley

Congratulations to my Ph.D. student Will Oakley on an excellent defense of his thesis!

Congratulations to Dr. Will Oakley for a successful defense of his Ph.D. dissertation, titled "Strong Consensus-Seeking in a Model of Social Consensus Formation"! pic.twitter.com/SxCEOkMpdr

— Mason Porter (@masonporter) June 4, 2020

An Awesome Ph.D. Defense by Dr. Yacoub Kureh!

Congratulations to my Ph.D. student Yacoub Kureh on an awesome defense of his thesis!

CONGRATULATIONS to Dr. Yacoub Kureh (@Yacoub_Kureh) on a successful and very impressive defense of his PhD thesis, called "Nonlinear opinion models and other networked systems"!!! pic.twitter.com/fXDNIE1GRX

— Mason Porter (@masonporter) May 28, 2020

Starting Out the Hard Way

I was the TA in the first course that Alex Vladimirsky (now the Director of the PhD program of my graduate alma mater) was ever in charge of.

Two decades later, I am still the most opinionated TA that he's ever had with respect to how to teach a course. People should get the most difficult person out of the way at the beginning, right?

He confirmed this and found out about the ducks at our meeting this morning! It’s perfect bc he tells me that when I need a debugging break, I should talk with a rubber duck, so I think the rubber duck that is living in the tex doc right now has a permanent home 😊 (for now)

— Mallory Gaspard (@mallorygaspard) May 27, 2020

A Spectacular Ph.D. Thesis Defense by Michelle Feng!

Congratulations to my Ph.D. student Michelle Feng on a superb defense of her thesis!

CONGRATULATIONS to Dr. Michelle Feng (@michellehfeng ) on a successful — and, in fact, spectacular — defense of her Ph.D. thesis, called "Topological Tools for Understanding Complex Systems"!!!!

You will be hearing a lot from her in the future. pic.twitter.com/gpjueTA6CW

— Mason Porter (@masonporter) April 28, 2020

"Quantifying “Political Islands” with Persistent Homology"

Here is a new expository article (in SIAM News) by my Ph.D. student Michelle Feng and me about our work on spatial topological data analysis.

I finally get to share my new @TheSIAMNews article (by @michellehfeng and me): "Quantifying “Political Islands” with Persistent Homology"https://t.co/ocpZN43EHg

— Mason Porter (@masonporter) January 28, 2020

You may also be interested in our associated research article and our recent follow-up article.

Quote of the Conference: Geodesic Spaces of Normal Shrinkage

"I call it 'geodesic spaces of normal shrinkage', in honor of George Costanza."

This may be the quote of the conference. The talk in question is this one.