Efficient Algorithms for Euclidean Steiner Minimal Tree on Near-Convex Terminal Sets
The Euclidean Steiner Minimal Tree problem takes as input a set P of points in the Euclidean plane and finds the minimum length network interconnecting all the points of P. In this paper, in continuation to the works of [Du et al., 1987] and [Weng and Booth, 1995], we study Euclidean Steiner Minimal Tree when P is formed by the vertices of a pair of regular, concentric and parallel n-gons.
We restrict our attention to the cases where the two polygons are not very close to each other. In such cases, we show that Euclidean Steiner Minimal Tree is polynomial-time solvable, and we describe an explicit structure of a Euclidean Steiner minimal tree for P.
We also consider point sets P of size n where the number of input points not on the convex hull of P is f(n) ≤ n. We give an exact algorithm with running time 2^𝒪(f(n) log n) for such input point sets P. Note that when f(n) = 𝒪(n/(log n)), our algorithm runs in single-exponential time, and when f(n) = o(n) the running time is 2^o(n log n) which is better than the known algorithm in [Hwang et al., 1992].
We know that no FPTAS exists for Euclidean Steiner Minimal Tree unless P = NP [Garey et al., 1977]. On the other hand FPTASes exist for Euclidean Steiner Minimal Tree on convex point sets [Scott Provan, 1988]. In this paper, we show that if the number of input points in P not belonging to the convex hull of P is 𝒪(log n), then an FPTAS exists for Euclidean Steiner Minimal Tree. In contrast, we show that for any ε ∈ (0,1], when there are Ω(n^ε) points not belonging to the convex hull of the input set, then no FPTAS can exist for Euclidean Steiner Minimal Tree unless P = NP.
Steiner minimal tree
Euclidean Geometry
Almost Convex point sets
FPTAS
strong NP-completeness
Theory of computation~Computational geometry
25:1-25:17
Regular Paper
https://arxiv.org/abs/2307.00254
Anubhav
Dhar
Anubhav Dhar
Indian Institute of Technology Kharagpur, India
Soumita
Hait
Soumita Hait
Indian Institute of Technology Kharagpur, India
Sudeshna
Kolay
Sudeshna Kolay
Indian Institute of Technology Kharagpur, India
10.4230/LIPIcs.ISAAC.2023.25
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Anubhav Dhar, Soumita Hait, and Sudeshna Kolay
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