Paul J. Steinhardt, P. Chaudhari
Journal of Computational Physics
We show that the semilattice extension problem raised by Arbib and Manes in [2] is NP-hard, implying that no simple solution is likely to be forthcoming. © 1983 Birkhäuser Verlag.
Paul J. Steinhardt, P. Chaudhari
Journal of Computational Physics
Ronen Feldman, Martin Charles Golumbic
Ann. Math. Artif. Intell.
James Lee Hafner
Journal of Number Theory
Vladimir Yanovski, Israel A. Wagner, et al.
Ann. Math. Artif. Intell.