Mahdi Haghifam

@mahdihaghifam.bsky.social

Researcher in ML and Privacy. PhD @UofT & @VectorInst. previously Research Intern @Google and @ServiceNowRSRCH https://mhaghifam.github.io/mahdihaghifam/

After grumbling for years in our substacks about uses and abuses of probability in machine learning, @beenwrekt.bsky.social and I decided it's finally time to put down some concrete ideas in a manifesto with a DOI. Here it is, give us your best feedback. (1/4)

Separating Geometry from Probability in the Analysis of Generalization

The goal of machine learning is to find models that minimize prediction error on data that has not yet been seen. Its operational paradigm assumes access to a dataset $S$ and articulates a scheme for ...

arxiv.org

Do you have recent work on differential privacy? Submit it to TPDP 2026 in Boston, whose deadline is in ~2 weeks. TPDP is a lightly reviewed workshop, whose main purpose is getting researchers in DP together in one place. Dual submissions allowed (and encouraged!).

Bild

I'm excited to share this paper. It answers a question that has bugged me for a long time: Can sample-and-aggregate be made more data-efficient? The answer is yes, but at a steep price in computational efficiency. See 🧵 for more details. Also, it was a fun opportunity to add a new coauthor. 😁

Differential Privacy Papers@dppapers.bsky.social · 11mo ago

Privately Estimating Black-Box Statistics Günter F. Steinke, Thomas Steinke http://arxiv.org/abs/2510.00322

Privately Estimating Black-Box Statistics

Günter F. Steinke, Thomas Steinke

http://arxiv.org/abs/2510.00322

Standard techniques for differentially private estimation, such as Laplace or
Gaussian noise addition, require guaranteed bounds on the sensitivity of the
estimator in question. But such sensitivity bounds are often large or simply
unknown. Thus we seek differentially private methods that can be applied to
arbitrary black-box functions. A handful of such techniques exist, but all are
either inefficient in their use of data or require evaluating the function on
exponentially many inputs. In this work we present a scheme that trades off
between statistical efficiency (i.e., how much data is needed) and oracle
efficiency (i.e., the number of evaluations). We also present lower bounds
showing the near-optimality of our scheme.

It took me a while, but I (finally) wrote a "short" (erm) note on the "polynomial+moments method" to prove testing or indistinguishability sample complexity lower bounds. Including the infamous Ω(k/log k) tolerant uniformity testing one. Comments and feedback welcome! 📝 github.com/ccanonne/pro...

One framed box from the note, which states that matching enough moments of a pair of suitable univariate random variables implies a sample complexity lower bound for the yes and no instances they correspond to.
Clément Canonne@ccanonne.github.io · last yr.

It was supposed to be a simple exposition, a short note about a lower bound technique. How is it already EIGHT PAGES LONG?

Excellent post from (my former😢 colleague) Nicholas Carlini on the differences between copyright law & privacy research. In particular, from a privacy perspective, "was training data memorized?" is a yes/no question; we aren't trying to quantify how much data was memorized beyond "some" vs "none".

What my privacy papers (don't) have to say about copyright and generative AI

My work on privacy-preserving machine learning is often cited by lawyers arguing for or against how generative AI models violate copyright. This maybe isn't the right work to be citing.

nicholas.carlini.com