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Gems of PODS

Talk 1: Datalog Unchained

Speaker: Victor Vianu (UC San Diego & INRIA)


This talk reviews the development, starting at PODS 1988, of a family of Datalog-like languages with procedural, forward chaining semantics, providing an alternative to the classical declarative, model-theoretic semantics. These languages provide a unified formalism that can express important classes of queries including fixpoint, while, and all computable queries. They can also incorporate in a natural fashion updates and nondeterminism. Datalog variants with forward chaining semantics have been adopted in a variety of settings, including active databases, production systems, distributed data exchange, and data-driven reactive systems.


Victor Vianu is a Professor in the Computer Science and Engineering department at U.C. San Diego. His research interests lay in database theory and computational logic. He has worked broadly on the theory of query languages, and is a co-author (with Serge Abiteboul and Richard Hull) of the book "Foundations of Databases". His most recent research focuses on the specification and verification of data‐driven workflows. Vianu received the PODS Alberto Mendelzon Test‐of‐Time award in 2010 and 2015, and the ICDT Test-of-Time award in 2019. He has been General Chair of SIGMOD and PODS, and Program Chair of PODS and ICDT. He has also served as editor‐in‐chief of the Journal of the ACM and is an area editor of ACM Transactions on Computational Logic. Vianu is a Fellow of the ACM and AAAS and a member of Academia Europaea.

Talk 2: Privacy: from Database Reconstruction to Legal Theorems

Speaker: Kobbi Nissim (Georgetown University)


There are significant gaps between legal and technical thinking around data privacy. As computer systems manipulating individual privacy-sensitive data become integrated in almost every aspect of society, and as such systems increasingly make decisions of legal significance, the need to bridge the legal and technical approaches becomes urgent.

We formulate and prove formal claims – “legal theorems” – addressing legal questions such as whether the use of technological measures satisfies the requirements of a legal privacy standard. In particular, we analyze the notion of singling out from the GDPR and whether technologies such as k-anonymity and differential privacy prevent singling out. Our long-term goal is to develop concepts which are on one hand technical, so they can be integrated in the design of computer systems, and can be used in legal reasoning and for policymaking on the other hand.


Kobbi Nissim is a Professor at the Department of Computer Science, Georgetown University, Affiliate Professor at Georgetown Law, and an Ethics Lab Faculty Affiliate. Prior to joining Georgetown, he was at the Department of Computer Science, Ben-Gurion University. From 2012 to 2017 he visited the Center for Research in Computation and Society (CRCS), Harvard University. He studied at the Weizmann Institute of Science, under the supervision of Prof. Moni Naor. Nissim works towards establishing rigorous practices for privacy in computation: identifying problems that result from the collection, sharing, and processing of information, formalizing these problems and studying them towards creating solid practices and technological solutions. He is the recipient of several prestigious awards, including the Godel Prize in 2017, the IACR TCC Test of Time Award in 2016, and the ACM PODS Alberto O. Mendelzon Test-of-Time Award in 2013.

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