On equations with sets as unknowns.

@article{Erds1968OnEW,
  title={On equations with sets as unknowns.},
  author={P Erd{\"o}s and S. Ulam},
  journal={Proceedings of the National Academy of Sciences of the United States of America},
  year={1968},
  volume={60 4},
  pages={1189-95}
}
  • P Erdös, S. Ulam
  • Published 1968 in
    Proceedings of the National Academy of Sciences…