European Symp. Algorithms (ESA)
The centroid of points with approximate weights.
M. Bern, D. Eppstein, L. J. Guibas, J. Hershberger, S. Suri, and J. Wolter.
3rd Eur. Symp. Algorithms, Corfu, 1995.
Springer, Lecture Notes in Comp. Sci. 979, 1995, pp. 460–472.Given a set of points with weights that are not known precisely, but are known to fall within some range, considers the possible weighted centroids arising from different choices of weights in each range. The combinatorics of this problem are closely connected with those of zonotopes.
Straight skeletons of three-dimensional polyhedra.
G. Barequet, D. Eppstein, M. T. Goodrich, and A. Vaxman.
arXiv:0805.0022.
Proc. 16th European Symp. Algorithms, Karlsruhe, Germany, 2008.
Springer, Lecture Notes in Comp. Sci. 5193, 2008, pp. 148–160.A straight skeleton is defined by the locus of points crossed by the edges and vertices of a polyhedron as it undergoes a continuous shrinking process in which the faces move inwards at constant speed. We resolve some ambiguities in the definition of these shapes, define efficient algorithms for polyhedra with axis-parallel faces, show that arbitrary polyhedra have strictly more complicated straight skeletons, and report on results from an implementation of our algorithm for arbitrary polyhedra.
Cloning Voronoi diagrams via retroactive data structures.
M. Dickerson, D. Eppstein, and M. T. Goodrich.
arXiv:1006.1921.
18th Eur. Symp. Algorithms, Liverpool, 2010.
Springer, Lecture Notes in Comp. Sci. 6346, 2010, pp. 362–373.We analyze the security of an online geometric database that allows planar nearest-neighbor queries but that does not wish the entire database to be copied by a competitor. We show that, under several models of how the query answers are returned, the database can be copied in a linear or near-linear number of queries. Our method for the competitor to copy the database is based on simulating Fortune's sweep-line algorithm for Voronoi diagrams, backtracking when the simulation discovers the existence of another point that invalidates earlier parts of the Voronoi diagram construction, and using retroactive data structures to perform the backtracking steps efficiently.
Bandwidth vs BFS width in matrix reordering, graph reconstruction, and graph drawing.
D. Eppstein, M. T. Goodrich, and S. Liu.
arXiv:2505.10789.
Proc. 33rd Annual European Symposium on Algorithms (ESA 2025).
Leibniz International Proceedings in Informatics (LIPIcs) 351, 2025, pp. 69:1–69:17.In graphs of bounded bandwidth, the number of vertices per level of a breadth-first search tree is at most polylogarithmic, with the exponent of the polylogarithm both upper and lower bounded by functions of the bandwidth. This has applications to the Cuthull-McKee heuristic and reverse Cuthull-McKee heuristic in sparse numerical algebra, to reconstructing an unknown graph by shortest distance queries, and to drawing graphs as arc diagrams of small height.