# Congratulations, Dr. Matias!

Pedro Ascensao Ferreira Matias, one of the students working with Mike Goodrich in the UC Irvine Center for Algorithms and Theory of Computation, passed his Ph.D. defense today.

Pedro is Portuguese, and came to UCI after a bachelor’s degree from the University of Coimbra in Portugal and a master’s degree from Chalmers University of Technology in Sweden.

The general topic of Pedro’s research is “exact learning”, the inference of structured information from queries or other smaller pieces of data. I’ve written here before about my work with Matias on nearest-neighbor chains and on tracking paths in planar graphs, the problem of placing sensors on a small subset of vertices so that, by detecting the order in which a path reaches each sensor, you can uniquely determine the whole path. His dissertation combines the tracking paths work with a second paper on tracking paths (“How to Catch Marathon Cheaters: New Approximation Algorithms for Tracking Paths”, arXiv:2104.12337, to appear at WADS 2021), and a paper on reconstructing periodic and near-periodic strings from sublinear numbers of queries (“Adaptive Exact Learning in a Mixed-Up World: Dealing with Periodicity, Errors and Jumbled-Index Queries in String Reconstruction”, arXiv:2007.08787, in SPIRE 2020). He also has recent papers on reconstructing trees in SPAA 2020 and ESA 2020.

After finishing his doctorate, Pedro’s next position will be working for Facebook.

Congratulations, Pedro!