×

On the multiple illumination numbers of convex bodies. (English) Zbl 1536.52005

Summary: In this paper, we introduce an \(m\)-fold illumination number \(I^m(K)\) of a convex body \(K\) in Euclidean space \(\mathbb{E}^d\), which is the smallest number of directions required to \(m\)-fold illuminate \(K\), i.e., each point on the boundary of \(K\) is illuminated by at least \(m\) directions. We get a lower bound of \(I^m(K)\) for any \(d\)-dimensional convex body \(K\), and get an upper bound of \(I^m(K)\) for any \(d\)-dimensional convex body \(K\) with smooth boundary. We also prove that \(I^m(K)=2m+1\), for a 2-dimensional smooth convex body \(K\). Furthermore, we obtain some results related to the \(m\)-fold illumination numbers of convex polygons and cap bodies of a \(d\)-dimensional unit ball \(\mathbb{B}^d\) in small dimensions. In particular, we show that \(I^m (P) = \lceil mn / \lfloor\frac{n-1}{2}\rfloor\rceil\), for a regular convex \(n\)-sided polygon \(P\).

MSC:

52A20 Convex sets in \(n\) dimensions (including convex hypersurfaces)
52A55 Spherical and hyperbolic convexity
52C17 Packing and covering in \(n\) dimensions (aspects of discrete geometry)

References:

[1] Artstein-Avidan, S.; Raz, O., Weighted covering numbers of convex sets, Adv. Math., 227, 730-744, 2011 · Zbl 1221.52026 · doi:10.1016/j.aim.2011.02.009
[2] Artstein-Avidan, S.; Slomka, BA, On weighted covering numbers and the Levi-Hadwiger conjecture, Israel J. Math., 209, 1, 125-155, 2015 · Zbl 1339.52014 · doi:10.1007/s11856-015-1213-5
[3] Bezdek, K., Illuminating spindle convex bodies and minimizing the volume of spherical sets of constant width, Discrete Comput. Geom., 47, 275-287, 2012 · Zbl 1246.52006 · doi:10.1007/s00454-011-9369-1
[4] Bezdek, K.; Bisztriczky, T., A proof of Hadwiger’s covering conjecture for dual cyclic polytopes, Geom. Dedicata, 68, 29-41, 1997 · Zbl 0965.52014 · doi:10.1023/A:1004965512469
[5] Bezdek, K.; Ivanov, I.; Strachan, C., Illuminating spiky balls and cap bodies, Discrete Math., 346, 1, 113135, 2023 · Zbl 1500.52005 · doi:10.1016/j.disc.2022.113135
[6] Boltyanskii, V., The problem of illuminating the boundary of a convex body, Izv. Mold. Fil. Akad. Nauk SSSR, 76, 77-84, 1960
[7] Boltyanskii, V., Solution of the illumination problem for belt-bodies, Mat. Zametki, 58, 505-511, 1995 · Zbl 0856.52014
[8] Boltyanskii, V., Solution of the illumination problem for bodies with md M = 2, Discrete Comput. Geom., 26, 527-541, 2001 · Zbl 1027.52002 · doi:10.1007/s00454-001-0035-x
[9] Boltyanski, V.; Martini, H., Combinatorial geometry of belt bodies, Results Math., 28, 224-249, 1995 · Zbl 0853.52004 · doi:10.1007/BF03322255
[10] Boltyanski, V.; Martini, H., Covering belt bodies by smaller homothetical copies, Beiträge Algebra Geom., 42, 313-324, 2001 · Zbl 0996.52015
[11] Boltyanskii, V.; Martini, H.; Soltan, PS, Excursions into Combinatorial Geometry, 1996, Berlin: Springer, Berlin
[12] Campos, M., Hintum, P.V., Morris, R., Tiba, M.: Towards Hadwiger’s conjecture via Bourgain slicing, pp. 1-10. arXiv:2206.11227 [math.MG] (2022)
[13] Gohberg, IT; Markus, AS, A certain problem about covering of convex sets with homothetic ones, Izv. Mold. Fil. Akad. Nauk SSSR., 10, 76, 87-90, 1960
[14] Hadwiger, H., Überdeckung einer Menge durch Mengen kleineren Durchmessers, Comment. Math. Helv., 18, 73-75, 1945 · Zbl 0063.01851 · doi:10.1007/BF02568103
[15] Hadwiger, H.: Ungelóste Probleme Nr. 20. Elem. Math. 12, 121 (1957)
[16] Hadwiger, H.: Ungelöste Probleme Nr. 38. Elem. Math. 15, 130-131 (1960)
[17] Huang, H.; Slomka, B.; Tkocz, T.; Vritsiou, B-H, Improved bounds for Hadwiger’s covering problem via thin-shell estimates, J. Eur. Math. Soc., 24, 1431-1448, 2022 · Zbl 1485.52004 · doi:10.4171/jems/1132
[18] Ivanov, I.; Strachan, C., On the illumination of centrally symmetric cap bodies in small dimensions, J. Geom., 112, 1-20, 2021 · Zbl 1466.52005 · doi:10.1007/s00022-020-00568-x
[19] Lassak, M., Solution of Hadwiger’s covering problem for centrally symmetric convex bodies in E3, J. Lond. Math. Soc., s2-30, 3, 501-511, 1984 · Zbl 0561.52017 · doi:10.1112/jlms/s2-30.3.501
[20] Levi, FW, Überdeckung eines Eibereiches durch Parallelverschiebungen seines offenen Kerns, Arch. Math., 6, 5, 369-370, 1955 · Zbl 0066.40603 · doi:10.1007/BF01900507
[21] Martini, H.: Some results and problems around zonotopes. In: Intuitive Geometry (Siófok, 1985), Colloq. Math. Soc. János Bolyai, vol. 48, pp. 383-418 (1987) · Zbl 0634.52007
[22] Minkowski, H., Volumen und Oberfläche, Math. Ann., 57, 447-495, 1903 · JFM 34.0649.01 · doi:10.1007/BF01445180
[23] Naszódi, M., Fractional illumination of convex bodies, Contrib. Discrete Math., 4, 83-88, 2009 · Zbl 1189.52005
[24] Naszódi, M., A spiky ball, Mathematika, 62, 2, 630-636, 2016 · Zbl 1346.52003 · doi:10.1112/S0025579315000406
[25] Naszódi, M.; Polyanskii, A., Approximating set multi-covers, Eur. J. Combin., 67, 174-180, 2018 · Zbl 1371.05203 · doi:10.1016/j.ejc.2017.08.001
[26] Papadoperakis, I., An estimate for the problem of illumination of the boundary of a convex body in E3, Geom. Dedicata, 75, 3, 275-285, 1999 · Zbl 0941.52016 · doi:10.1023/A:1005056207406
[27] Prymak, A., A new bound for Hadwiger’s covering problem in E3, SIAM J. Numer. Anal., 37, 1, 17-24, 2023 · Zbl 1518.52010
[28] Prymak, A., Shepelska, V.: On illumination of the boundary of a convex body in En, n = 4,5,6, pp. 1-12. arXiv:1811.08962v3 [math.MG] (2020)
[29] Rogers, CA; Zong, C., Covering convex bodies by translates of convex bodies, Mathematika, 44, 215-218, 1997 · Zbl 0884.52018 · doi:10.1112/S0025579300012079
[30] Schramm, O., Illuminating sets of constant width, Mathematika, 35, 180-189, 1988 · Zbl 0663.52006 · doi:10.1112/S0025579300015175
[31] Talata, I., Solution of Hadwiger-Levi’s covering problem for duals of cyclic 2k-polytopes, Geom. Dedicata, 74, 61-71, 1999 · Zbl 0928.52005 · doi:10.1023/A:1005003719969
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. In some cases that data have been complemented/enhanced by data from zbMATH Open. This attempts to reflect the references listed in the original paper as accurately as possible without claiming completeness or a perfect matching.