Super-Logarithmic Lower Bounds for Dynamic Graph Problems

In this work, we prove a (Omega) over tilde (lg(3/2) n) unconditional lower bound on the maximum of the query time and update time for dynamic data structures supporting reachability queries in n-node directed acyclic graphs under edge insertions. This is the first super-logarithmic lower bound for any natural graph problem. In proving the lower bound, we also make novel contributions to the state-of-the-art data structure lower bound techniques that we hope may lead to further progress in proving lower bounds.