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Asymptotic distribution of the numbers of vertices and arcs of the giant strong component in sparse random digraphs
- Source :
- Random Structures & Algorithms. 49:3-64
- Publication Year :
- 2015
- Publisher :
- Wiley, 2015.
-
Abstract
- Two models of a random digraph on n vertices, D(n; Prob(arc) = p) and D(n; number of arcs = m) are studied. In 1990, Karp for D(n;p) and independently T. Luczak for D(n;m = cn) proved that for c > 1, with probability tending to 1, there is an unique strong component of size of order n. Karp showed, in fact, that the giant component has likely size asymptotic to n 2 , where = (c) is the unique positive root of 1 = e c . In this paper we prove that, for both random digraphs, the joint distribution of the number of vertices and number of arcs in the giant strong component is asymptotically Gaussian with the same mean vector n (c), (c) := ( 2 ;c 2 ) and two distinct 2 2 covariance matrices, nB(c) and n B(c) +c( 0 (c)) T ( 0 (c))) . To this end, we introduce and analyze a randomized deletion process which determines the directed (1; 1)-core, the maximal digraph with minimum in-degree and out-degree at least 1. This (1; 1)-core contains all nontrivial strong components. However, we show that the likely numbers of peripheral vertices and arcs in the (1; 1)-core, those outside the largest strong component, are of polylog order, thus dwarfed by anticipated uctuations, on the scale of n 1=2 , of the giant component parameters. By approximating the likely realization of the deletion algorithm with a deterministic trajectory, we obtain our main result via exponential supermartingales and Fourier-based techniques.
- Subjects :
- Discrete mathematics
Applied Mathematics
General Mathematics
Asymptotic distribution
Digraph
0102 computer and information sciences
Covariance
01 natural sciences
Computer Graphics and Computer-Aided Design
Giant component
010101 applied mathematics
Combinatorics
010201 computation theory & mathematics
Joint probability distribution
Order (group theory)
0101 mathematics
Realization (systems)
Software
Central limit theorem
Mathematics
Subjects
Details
- ISSN :
- 10429832
- Volume :
- 49
- Database :
- OpenAIRE
- Journal :
- Random Structures & Algorithms
- Accession number :
- edsair.doi...........f1cbd162f9d224df664c7c4d82f2186f