P, NP, and the Post Correspondence Problem

Information and Computation - Tập 121 - Trang 135-142 - 1995
A. Mateescu1, A. Salomaa1, K. Salomaa1, S. Yu1
1Univ Western Ontario, Dept Comp Sci, London, ON N6A 5B7, Canada; Acad Finland, SF 20500 Turku, Finland and Univ Turku, Dept Math, SF 20500 Turku, Finland