Dr. Chatzidakis was an International Congress of Mathematicians speaker, winner of the 2013 Leconte Prize, MSRI Chern Professor and Director of the CNRS lab at École normale supérieure. In 2020 she was invited to deliver the Tarski Lectures, an event thwarted by the COVID-19 pandemic. To her field’s loss, she never delivered the lectures.

As an advocate for the greater mathematics community, she was an instigator on many grant proposals which brought funding and made opportunities for young model theorists. Of special note is Modnet, which was a European-funded network for five years, but Dr. Chatzidakis maintained the website for many years afterwards, including job openings for young people and lists of preprints. She organized many of the thematic programs at MSRI, Newton Institute and the Institut Henri Poincaré.

Dr. Chatzidakis was a fixed presence at the Fields Institute from its earliest days. She grew to love Toronto after participating in the year-long Geometry and Model Theory Seminar from 1996-1997, where she formed close, lifelong relationships. Her last visit here, in 2021, was for a workshop co-organized by Rahim Moosa, who first met her at the 1996 seminar. In fact, the six-month Thematic Program in Model Theory was based on that 1996 seminar. As Dr. Moosa recalls, the program was an early effort at returning to in-person mathematical collaboration and “Zoé’s spirited presence was a significant factor in its success.” Dr. Chatzidakis was scheduled to come back for a June 2025 program, where she had agreed to speak at a workshop. Her name still appears as a speaker on the workshop webpage.

Well beyond her mathematical gifts, friends remember Dr. Chatzidakis for her strong opinions, striking presence and a champion of doing the right thing. Fields Director, Deirdre Haskell, acknowledges that for those who didn’t know her well, she could present an intimidating figure.

“It could be very scary to give a talk with her in the audience, as no oversimplification or incorrect definition would be allowed to slip by. As I remarked to another friend, her bark was worse than her bite, but that bark could be rough. She wasn’t really aware of how she came across; for her it was just about understanding the mathematics and making sure that things were stated correctly. She worked tirelessly for the advancement of the subject,” Haskell says.

Often, her fearless push to get the mathematics right led to memorable moments. Most notable is her famous interaction with French mathematician Bruno Poizat. As Bradd Hart recalls, “Bruno would only give his talks in French no matter where he was and, at Oberwolfach many years ago, Zoé was asked to translate a lecture by Bruno in real-time. The interaction was hilarious, but the most telling was that in the middle of the lecture, while Zoé was translating, she stopped and looked puzzled at Bruno. What ensued in French was a rapid-fire mathematical “argument,” the ending of which saw Bruno retract his claim, make a different claim and proceed to give Zoé’s proof.”

Hart notes that Dr. Chatzidakis was a useful critic when one was a conference organizer, which is the best kind of critic. She would lobby for problem sessions, speaking opportunities for students and postdocs, and let you know if your speaker lineup was too elitist. He personally remembers organizing a meeting at Fields where she rearranged a dinner to be more inclusive and she, of course, was right. She was very engaged with the community and often fought on behalf of the underrepresented. Of particular note is her efforts to keep the unjust imprisonments of Turkish mathematicians Ali Nesin and Tuna Altinel in everyone’s eyesight. 

Anecdotally, Dr. Moosa shares what it was like to have her in your corner. “While still a graduate student in Illinois I spent the last four months of 1999 in Paris, under mostly Zoé’s supervision. This was when I proved my first real theorem; it was collaborative work with Zoé but she was too generous to put her name on the paper. Anyway, one of the logistic difficulties I had when I first arrived was that the bank would not let me open an account due to my temporary status; I found the bank manager unmovable. I told Zoé about it. She accompanied me to the bank that very afternoon and shouted so long and hard at the manager that he was cowed into submission. I left that day with a new bank account and a newfound respect for the force of Zoé’s will.

Dr. Chatzidakis leaves a hole in the field and in the lives of those she knew. As her close friend Dr. Haskell observes, echoing the sentiments of many, “She was a role model for generations of model theorists and I admired her enormously.”