{"title":"凸位置点的θ图的角度单调性","authors":"D. Bakhshesh, M. Farshi","doi":"10.24200/sci.2023.61034.7110","DOIUrl":null,"url":null,"abstract":"For a real number 0 < γ < 180 ◦ , a geometric path P = ( p 1 , . . . , p n ) is called angle-monotone with width γ from p 1 to p n if there exists a closed wedge of angle γ such that every directed edge −−−−→ p i p i +1 of P lies inside the wedge whose apex is p i . A geometric graph G is called angle-monotone with width γ if for any two vertices p and q in G , there exists an angle-monotone path with width γ from p to q . In this paper, we show that for any integer k ≥ 1 and any i ∈ { 2 , 3 , 4 , 5 } , the theta-graph Θ 4 k + i on a set of points in convex position is angle-monotone with width 90 ◦ + iθ 4 , where θ = 360 ◦ 4 k + i . Moreover, we present two sets of points in the plane, one in convex position and the other in non-convex position, to show that for every 0 < γ < 180 ◦ , the graph Θ 4 is not angle-monotone with width γ . ,","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":null,"pages":null},"PeriodicalIF":1.4000,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Angle-monotonicity of theta-graphs for points in convex position\",\"authors\":\"D. Bakhshesh, M. Farshi\",\"doi\":\"10.24200/sci.2023.61034.7110\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"For a real number 0 < γ < 180 ◦ , a geometric path P = ( p 1 , . . . , p n ) is called angle-monotone with width γ from p 1 to p n if there exists a closed wedge of angle γ such that every directed edge −−−−→ p i p i +1 of P lies inside the wedge whose apex is p i . A geometric graph G is called angle-monotone with width γ if for any two vertices p and q in G , there exists an angle-monotone path with width γ from p to q . In this paper, we show that for any integer k ≥ 1 and any i ∈ { 2 , 3 , 4 , 5 } , the theta-graph Θ 4 k + i on a set of points in convex position is angle-monotone with width 90 ◦ + iθ 4 , where θ = 360 ◦ 4 k + i . Moreover, we present two sets of points in the plane, one in convex position and the other in non-convex position, to show that for every 0 < γ < 180 ◦ , the graph Θ 4 is not angle-monotone with width γ . ,\",\"PeriodicalId\":21605,\"journal\":{\"name\":\"Scientia Iranica\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.4000,\"publicationDate\":\"2023-07-18\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Scientia Iranica\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://doi.org/10.24200/sci.2023.61034.7110\",\"RegionNum\":4,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"ENGINEERING, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Scientia Iranica","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.24200/sci.2023.61034.7110","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
摘要
对于实数 0 < γ < 180 ◦ ,如果存在一个角度为 γ 的封闭楔形,使得 P 的每条有向边 ----→ p i p i +1 都位于顶点为 p i 的楔形内,则从 p 1 到 p n 的几何路径 P = ( p 1 , ... , p n ) 称为宽度为 γ 的角单调路径。如果对于 G 中的任意两个顶点 p 和 q,存在一条宽度为 γ 的角单调路径从 p 到 q,则称几何图形 G 为宽度为 γ 的角单调图。在本文中,我们证明对于任意整数 k ≥ 1 和任意 i ∈ { 2 , 3 , 4 , 5 } ,θ 图 Θ 的宽度为 γ 。凸位置点集合上的θ图 Θ 4 k + i 是角度单调的,宽度为 90 ◦ + iθ 4,其中 θ = 360 ◦ 4 k + i 。此外,我们提出了平面上的两组点,一组处于凸位置,另一组处于非凸位置,以说明对于每 0 < γ < 180 ◦,图形 Θ 4 都不是宽度为 γ 的角单调图形。,
Angle-monotonicity of theta-graphs for points in convex position
For a real number 0 < γ < 180 ◦ , a geometric path P = ( p 1 , . . . , p n ) is called angle-monotone with width γ from p 1 to p n if there exists a closed wedge of angle γ such that every directed edge −−−−→ p i p i +1 of P lies inside the wedge whose apex is p i . A geometric graph G is called angle-monotone with width γ if for any two vertices p and q in G , there exists an angle-monotone path with width γ from p to q . In this paper, we show that for any integer k ≥ 1 and any i ∈ { 2 , 3 , 4 , 5 } , the theta-graph Θ 4 k + i on a set of points in convex position is angle-monotone with width 90 ◦ + iθ 4 , where θ = 360 ◦ 4 k + i . Moreover, we present two sets of points in the plane, one in convex position and the other in non-convex position, to show that for every 0 < γ < 180 ◦ , the graph Θ 4 is not angle-monotone with width γ . ,
期刊介绍:
The objectives of Scientia Iranica are two-fold. The first is to provide a forum for the presentation of original works by scientists and engineers from around the world. The second is to open an effective channel to enhance the level of communication between scientists and engineers and the exchange of state-of-the-art research and ideas.
The scope of the journal is broad and multidisciplinary in technical sciences and engineering. It encompasses theoretical and experimental research. Specific areas include but not limited to chemistry, chemical engineering, civil engineering, control and computer engineering, electrical engineering, material, manufacturing and industrial management, mathematics, mechanical engineering, nuclear engineering, petroleum engineering, physics, nanotechnology.