Pseudorandom Graphs for Logical Adversaries
Speaker: JamieTitle: Pseudorandom Graphs for Logical Adversaries
Date: 02 Feb 2023 17:30-19:00 EST
Location: SEC Level 3 NW Terrace
Food: Pizza
I will present my recent work (with Jan Dreier at TU Wien) on explicitly constructing graphs (and hypergraphs) that are pseudorandom in the sense that they are indistinguishable from Erdős–Rényi graphs by testing for properties that are expressible in a primitive logic. For first order logic, this amounts to constructing existentially-closed graphs, a notoriously difficult problem from graph theory. I will explain what these graphs are, mention some interesting open questions about them, and briefly describe our new technique based on existing theorems in the derandomization literature. I will then talk about how to implement such constructions for hypergraphs by applying simple transformations of random graphs, where these transformations must themselves be definable in a primitive logic as well. This amounts to an interesting analog of pseudorandom generators that becomes equivalent to the standard model in cryptography when we consider an extension of first order logic called fixed point logic with parity.