Logic List Mailing Archive

Zoe Chatzidakis (1955-2025)

Zo Chatzidakis (3 April 1955--22 January 2025)

In Memoriam by the Fields Institute
https://www.fields.utoronto.ca/news/Memoriam-Dr-Zo%C3%A9-Chatzidakis

Fields is saddened to learn of the passing of Dr. Zo Chatzidakis, a bril
liant mathematician, loyal friend, fierce advocate for her subject and stro
ng supporter of women and young people. She died on the morning of January 
22, 2025.

Dr. Chatzidakis was an International Congress of Mathematicians speaker, wi
nner of the 2013 Leconte Prize, MSRI Chern Professor and Director of the CN
RS lab at cole normale suprieure. In 2020 she was invited to deliver 
the Tarski Lectures, an event thwarted by the COVID-19 pandemic. To her fie
ld'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 y
oung model theorists. Of special note is Modnet, which was a European-funde
d network for five years, but Dr. Chatzidakis maintained the website for ma
ny years afterwards, including job openings for young people and lists of p
reprints. She organized many of the thematic programs at MSRI, Newton Insti
tute and the Institut Henri Poincar.

Dr. Chatzidakis was a fixed presence at the Fields Institute from its earli
est days. She grew to love Toronto after participating in the year-long Geo
metry and Model Theory Seminar from 1996-1997, where she formed close, life
long relationships. Her last visit here, in 2021, was for a workshop co-org
anized 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-pe
rson mathematical collaboration and "Zo's spirited presence was a signif
icant factor in its success." Dr. 

Chatzidakis was scheduled to come back for a June 2025 program, where she h
ad agreed to speak at a workshop. Her name still appears as a speaker on th
e workshop webpage.

Well beyond her mathematical gifts, friends remember Dr. Chatzidakis for he
r strong opinions, striking presence and a champion of doing the right thin
g. 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 over
simplification or incorrect definition would be allowed to slip by. As I re
marked to another friend, her bark was worse than her bite, but that bark c
ould be rough. She wasn't really aware of how she came across; for her it w
as just about understanding the mathematics and making sure that things wer
e stated correctly. She worked tirelessly for the advancement of the subjec
t," Haskell says.

Often, her fearless push to get the mathematics right led to memorable mome
nts. 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, Zo 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 Zo w
as translating, she stopped and looked puzzled at Bruno. What ensued in Fre
nch was a rapid-fire mathematical "argument," the ending of which saw Bruno
 retract his claim, make a different claim and proceed to give Zo's proo
f."

Hart notes that Dr. Chatzidakis was a useful critic when one was a conferen
ce organizer, which is the best kind of critic. She would lobby for problem
 sessions, speaking opportunities for students and postdocs, and let you kn
ow if your speaker lineup was too elitist. He personally remembers organizi
ng a meeting at Fields where she rearranged a dinner to be more inclusive a
nd she, of course, was right. She was very engaged with the community and o
ften fought on behalf of the underrepresented. Of particular note is her ef
forts 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 Zo's supervision. This was when I proved my
 first real theorem; it was collaborative work with Zo but she was too g
enerous to put her name on the paper. Anyway, one of the logistic difficult
ies I had when I first arrived was that the bank would not let me open an a
ccount due to my temporary status; I found the bank manager unmovable. I to
ld Zo about it. She accompanied me to the bank that very afternoon and s
houted 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 Zo's will.

Dr. Chatzidakis leaves a hole in the field and in the lives of those she kn
ew. As her close friend Dr. Haskell observes, echoing the sentiments of man
y, "She was a role model for generations of model theorists and I admired h
er enormously."
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