کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4651902 1632582 2015 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
On the zone of a circle in an arrangement of lines
ترجمه فارسی عنوان
در منطقه یک دایره در یک ترتیب از خطوط
موضوعات مرتبط
مهندسی و علوم پایه ریاضیات ریاضیات گسسته و ترکیبات
چکیده انگلیسی

Let L be a set of n lines in the plane, and let C be a convex curve in the plane, like a circle or a parabola. The zone of C in L, denoted Z(C,L), is defined as the set of all faces in the arrangement A(L) that are intersected by C. Edelsbrunner et al. (1992) showed that the complexity (total number of edges or vertices) of Z(C,L) is at most O(nα(n)), where α is the inverse Ackermann function, by translating the sequence of edges of Z(C,L) into a sequence S that avoids the subsequence ababa. Whether the worst-case complexity of Z(C,L) is only linear is a longstanding open problem.In this paper we provide evidence that, if C is a circle or a parabola, then the zone of C has at most linear complexity: We show that a certain configuration of segments with endpoints on C is impossible. As a consequence, the Hart–Sharir sequences, which are essentially the only known way to construct ababa-free sequences of superlinear length, cannot occur in S.Hence, if it could be shown that every family of superlinear-length, ababa-free sequences must eventually contain all Hart–Sharir sequences, that would settle the zone problem for a circle/parabola.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Electronic Notes in Discrete Mathematics - Volume 49, November 2015, Pages 221-231