We prove that O(e " t'/gT-~g~") states are sufficient to simulate an n-state lnfa recognizing a unary language by a ldfa. The lower bound is the same. Similar tight bounds are shown for theâ€¦ (More)

We consider the problem of embedding the vertices of a plane graph into a small (polynomial size) grid in the plane in such a way that the edges are straight, non-intersecting line segments and facesâ€¦ (More)

We investigate the k-server problem when the metric space is a tree. For this case we present an on-line k-competitive algorithm for k servers. The competitiveness ratio k is optimal. The algorithmâ€¦ (More)

Tomography is the area of reconstructing objects from projections. In discrete tomography an object T we wish to reconstruct may be a set of cells of a multidimensional grid. We perform measurementsâ€¦ (More)

We consider the problem of orienting the edges of a planar graph in such a way that the out-degree of each vertex is minimized. If, for each vertex v, the out-degree is at most d, then we say thatâ€¦ (More)

In the k-server problem, we must choose how k mobile servers will serve each of a sequence of requests, making our decisions in an online manner. We exhibit an optimai deterministic online strategyâ€¦ (More)