In a framework with two parties, deterministic voter preferences and a type of geographical constraints, we propose a set of simple axioms and show that they jointly characterize the districting rule that maximizes the number of districts one party can win, given the distribution of individual votes (the " optimal gerrymandering rule "). As a corollary, we obtain that no districting rule can sa...

This paper introduces reachability logic, a language-independent seven-rule proof system for deriving reachability properties of systems. The key ingredients of reachability logic are its sentences, which are called reachability rules and generalize the transitions of operational semantics and the Hoare triples of axiomatic semantics, and the Circularity proof rule, which generalizes invariant ...