Stem nonempti$ (all stems)
2 papers:
FoSSaCS-2009-KupfermanP #automaton #bound- Lower Bounds on Witnesses for Nonemptiness of Universal Co-Büchi Automata (OK, NP), pp. 182–196.
CSL-1998-Vorobyov #functional #type system- Subtyping Functional+Nonempty Record Types (SGV), pp. 283–297.










