Year 2000 problem | Versus | Waring's problem | The Final Problem | Mega Shark Versus Giant Octopus | The Problem with Popplers | NHL on Versus | Hume and the Problem of Causation | Dirichlet problem | Boolean satisfiability problem | Versus (film) | The Dog Problem | Tammes problem | Species problem | Real versus nominal value | problem solving | Problem gambling | Player versus environment | Patton Versus Rommel | Packing problem | packing problem | Girls Versus Suits | chess problem | Casino Versus Japan | Znám's problem | Year 10,000 problem | Yamabe problem | Weber problem | Versus (TV channel) | Versus (band) |
With Wolfgang Paul, Nick Pippenger, and William Trotter, he established a separation between nondeterministic linear time and deterministic linear time, in the spirit of the infamous P versus NP problem.