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Timo Vilkas
Senior lecturer
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Competing frogs on zd
Author
Summary, in English
A two-type version of the frog model on Zd is formulated, where active type i particles move according to lazy random walks with probability pi of jumping in each time step (i = 1, 2). Each site is independently assigned a random number of particles. At time 0, the particles at the origin are activated and assigned type 1 and the particles at one other site are activated and assigned type 2, while all other particles are sleeping. When an active type i particle moves to a new site, any sleeping particles there are activated and assigned type i, with an arbitrary tie-breaker deciding the type if the site is hit by particles of both types in the same time step. Let Gi denote the event that type i activates infinitely many particles. We show that the events G1 ∩ Gc2 and Gc1 ∩ G2 both have positive probability for all p1, p2 ∈ (0, 1]. Furthermore, if p1 = p2, then the types can coexist in the sense that the event G1 ∩ G2 has positive probability. We also formulate several open problems. For instance, we conjecture that, when the initial number of particles per site has a heavy tail, the types can coexist also when p1 ≠ p2.
Publishing year
2019
Language
English
Publication/Series
Electronic Journal of Probability
Volume
24
Document type
Journal article
Publisher
UNIV WASHINGTON, DEPT MATHEMATICS
Topic
- Probability Theory and Statistics
Keywords
- Coexistence
- Competing growth
- Frog model
- Random walk
Status
Published
ISBN/ISSN/Other
- ISSN: 1083-6489