A simple proof that the (n2 − 1)-puzzle is hard

Winning Ways for Your Mathematical Plays.

R. J. Connelly, Elwyn R. Berlekamp, John H. Conway et al. · American Mathematical Monthly · 1986 · 1.5K citations

Natural Sciences, Mathematics, Combinatorics +5

The Rectilinear Steiner Tree Problem is $NP$-Complete

M. R. Garey, David S. Johnson · SIAM Journal on Applied Mathematics · 1977 · 1.1K citations

Natural Sciences, Computer Science, Mathematics +12

On Steiner’s Problem with Rectilinear Distance

M. Hanan · SIAM Journal on Applied Mathematics · 1966 · 624 citations

Natural Sciences, Industrial Engineering, Mathematics +14

Proceedings 35th Annual Symposium on Foundations of Computer Science

1994 · 595 citations

Computing, Computer Science, Algorithms +14

Coordinating Pebble Motion On Graphs, The Diameter Of Permutation Groups, And Applications

Daniel Kornhauser, Gary L. Miller, Paul G. Spirakis · 1984 · 285 citations · Full text

Natural Sciences, Computer Science, Mathematics +11