Felix Zhou
felix-zhou-cfz.bsky.social
Felix Zhou
@felix-zhou-cfz.bsky.social
CS PhD student @Yale

Algorithms, Differential Privacy, Machine Learning

http://felix-zhou.com
An interesting and somewhat counterintuitive feature: we get better private streaming algorithms by actually making the input larger!
October 18, 2025 at 5:22 PM
The question of whether we can obtain a poly(d, 1/ERR, k) time algorithm is still open, so jump right in!

(7/7)
April 19, 2025 at 5:39 PM
We make a conceptual connection to learning with coarsened samples.
Through this connection, we derive an SGD-based algorithm with poly(d, 1/ERR) + k^O(k) running time.

(6/7)
April 19, 2025 at 5:39 PM
Gaitonde and Mossel improved this to poly(d) * (log(k)/ERR)^O(k) time, also using a moment-based algorithm.

(5/7)
April 19, 2025 at 5:39 PM
Surprisingly, Cherapanamjeri, Daskalakis, @aifi.bsky.social, and Zampetakis recently designed a moment-based algorithm with poly(d) * exp(k/ERR) running time to recover the k-linear regression parameters up to error ERR in ambient dimension d.

(4/7)
April 19, 2025 at 5:39 PM
Inference under selection biases has been extensively studied, starting with the works of Roy, Heckman, Willis and Rosen, and Fair and Jaffee.

Despite this extensive history, efficient algorithms for
estimation under self-selection was not known.

(3/7)
April 19, 2025 at 5:39 PM
Self-selection bias occurs when data is systematically selected rather than randomly sampled:
Assuming individuals choose the profession for which they are most successful, we would only observe the maximum of k outcomes.

(2/7)
April 19, 2025 at 5:39 PM