The Contact Process on Trees
| dc.creator | Pemantle, Robin | |
| dc.date | 2004-04-02 | |
| dc.date.accessioned | 2026-07-07T05:07:02Z | |
| dc.date.available | 2026-07-07T05:07:02Z | |
| dc.description | The contact process on an infinite homogeneous tree is shown to exhibit at least two phase transitions as the infection parameter lambda is varied. For small values of lambda a single infection eventually dies out. For larger lambda the infection lives forever with positive probability but eventually leaves any finite set. (The survival probability is a continuous function of lambda, and the proof of this is much easier than it is for the contact process on d-dimensional integer lattices.) For still larger lambda the infection converges in distribution to a nontrivial invariant measure. For an n-ary tree, with n large, the first of these transitions occurs when lambda~1/n and the second occurs when 1/2 sqrt{n}<lambda<e/sqrt{n}. Nonhomogeneous trees whose vertices have degrees varying between 1 and n behave essentially as homogeneous n-ary trees, provided that vertices of degree n are not too rare. In particular, letting n go to infty, Galton-Watson trees whose vertices have degree n with probability that does not decrease exponentially with n may have both phase transitions occur together at lambda=0. The nature of the second phase transition is not yet clear and several problems are mentioned in this regard. | |
| dc.description | 41 pages | |
| dc.identifier | https://arxiv.org/abs/math/0404046 | |
| dc.identifier | http://arxiv.org/abs/math/0404046 | |
| dc.identifier | Ann. Probab., 20, 2089 - 2116 (1992) | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/70703 | |
| dc.subject | Probability | |
| dc.subject | 60K35 | |
| dc.title | The Contact Process on Trees | |
| dc.type | text |