On the size of the block of 1 for Ξ -coalescents with dust
Volume 4, Issue 4 (2017), pp. 407–425
Pub. online: 27 December 2017
Type: Research Article
Open Access
Received
28 August 2017
28 August 2017
Revised
4 December 2017
4 December 2017
Accepted
6 December 2017
6 December 2017
Published
27 December 2017
27 December 2017
Abstract
We study the frequency process $f_{1}$ of the block of 1 for a Ξ-coalescent Π with dust. If Π stays infinite, $f_{1}$ is a jump-hold process which can be expressed as a sum of broken parts from a stick-breaking procedure with uncorrelated, but in general non-independent, stick lengths with common mean. For Dirac-Λ-coalescents with $\varLambda =\delta _{p}$, $p\in [\frac{1}{2},1)$, $f_{1}$ is not Markovian, whereas its jump chain is Markovian. For simple Λ-coalescents the distribution of $f_{1}$ at its first jump, the asymptotic frequency of the minimal clade of 1, is expressed via conditionally independent shifted geometric distributions.
References
Kersting, G., Schweinsberg, J., Wakolbinger, A.: The size of the last merger and time reversal in Λ-coalescents. ArXiv e-prints (2017). 1701.00549