Motions of a short-linked robot arm in a square

The main result of this paper is anO(n)-time algorithm to determine whether a given configuration of ann-link short-linked robot arm confined in a square can be reached from another given configuration. The arm is constructed fromn links, which are straight line segments of real lengths, each no greater than half the side length of the confining square. This result represents a continuation of previous work published by Hopcroftet al. and by Kantabutra and Kosaraju.