Abstract
Suppose a configurationX consists ofn points lying on a circle of radiusr. If at most one of the edges joining neighboring points has length strictly greater thanr, then the Steiner treeS consists of all these edges with a longest edge removed. In order to showS is, in fact, just the minimal spanning treeT, a variational approach is used to show the Steiner ratio for this configuration is at least one and equals one only ifS andT coincide. The variational approach greatly reduces the number of possible Steiner trees that need to be considered.
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D. Z. Du, F. K. Hwang, and S. C. Chao, Steiner Minimal Tree for Points on a Circle,Proc. Amer. Math. Soc.,95 (1985), 613–618.
M. R. Garey, R. L. Graham, and D. S. Johnson, The Complexity of Computing Steiner Minimal Trees,SIAM J. Appl. Math.,32 (1977), 835–859.
E. N. Gilbert and H. O. Pollak, Steiner Minimal Trees,SIAM J. Appl. Math.,16 (1968), 1–29.
R. L. Graham, Some Results on Steiner Minimal Trees, Unpublished manuscript dated 11 May 1967.
Z. A. Melzak, On the Problem of Steiner,Canad. Math. Bull,4 (1961), 143–148.
H. O. Pollak, Some Remarks on the Steiner Problem,J. Combin. Theory Ser. A,24 (1978), 278–295.
J. H. Rubinstein and D. A. Thomas, A Variational Approach to the Steiner Network Problem, Preprint.
J. H. Rubinstein and D. A. Thomas, Critical Points for the Steiner Ratio Conjecture, Preprint.
J. H. Rubinstein and D. A. Thomas, The Steiner Ratio Conjecture for Cocircular Points, Preprint.
J. H. Rubinstein and D. A. Thomas, The Steiner Ratio Conjecture for Six Points, Preprint.
J. H. Rubinstein, D. A. Thomas, and J. F. Weng, Degree Five Steiner Points Cannot Reduce Network Costs for Planar Sets, Preprint.
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Communicated by F. K. Hwang.
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Rubinstein, J.H., Thomas, D.A. Graham's problem on shortest networks for points on a circle. Algorithmica 7, 193–218 (1992). https://doi.org/10.1007/BF01758758
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DOI: https://doi.org/10.1007/BF01758758