{"title":"Markovian Dynamics of Exchangeable Arrays","authors":"J. vCern'y, A. Klimovsky","doi":"10.1142/9789811206092_0005","DOIUrl":"https://doi.org/10.1142/9789811206092_0005","url":null,"abstract":"We study Markov processes with values in the space of general two-dimensional arrays whose distribution is exchangeable. The results of this paper are inspired by the theory of exchangeable dynamical random graphs developed by H. Crane (2016, 2017).","PeriodicalId":163241,"journal":{"name":"Genealogies of Interacting Particle Systems","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122077006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On Projections of the Supercritical Contact Process: Uniform Mixing and Cutoff Phenomenon","authors":"Stein Andreas Bethuelsen","doi":"10.1142/9789811206092_0009","DOIUrl":"https://doi.org/10.1142/9789811206092_0009","url":null,"abstract":"We consider the contact process on a countable-infinite and connected graph of bounded degree. For this process started from the upper invariant measure, we prove certain uniform mixing properties under the assumption that the infection parameter is sufficiently large. In particular, we show that the projection of such a process onto a finite subset forms a process which is $phi$-mixing. The proof of this is based on large deviation estimates for the spread of an infection and general correlation inequalities. In the special case of the contact process on $mathbb{Z}^d$, $dgeq1$, we furthermore prove the cutoff phenomenon, valid in the entire supercritical regime.","PeriodicalId":163241,"journal":{"name":"Genealogies of Interacting Particle Systems","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114461159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Stochastic Evolution of Genealogies of Spatial Populations: State Description, Characterization of Dynamics and Properties","authors":"A. Depperschmidt, A. Greven","doi":"10.1142/9789811206092_0002","DOIUrl":"https://doi.org/10.1142/9789811206092_0002","url":null,"abstract":"We survey results on the description of stochastically evolving genealogies of populations and marked genealogies of multitype populations or spatial populations via tree-valued Markov processes on (marked) ultrametric measure spaces. In particular we explain the choice of state spaces and their topologies, describe the dynamics of genealogical Fleming-Viot and branching models by well-posed martingale problems, and formulate the typical results on the longtime behavior. Furthermore we discuss the basic techniques of proofs and sketch as two key tools of analysis the different forms of duality and the Girsanov transformation.","PeriodicalId":163241,"journal":{"name":"Genealogies of Interacting Particle Systems","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116542014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"PATRICIA Bridges","authors":"Steven N. Evans, A. Wakolbinger","doi":"10.1142/9789811206092_0006","DOIUrl":"https://doi.org/10.1142/9789811206092_0006","url":null,"abstract":"A radix sort tree arises when storing distinct infinite binary words in the leaves of a binary tree such that for any two words their common prefixes coincide with the common prefixes of the corresponding two leaves. If one deletes the out-degree $1$ vertices in the radix sort tree and \"closes up the gaps\", then the resulting PATRICIA tree maintains all the information that is necessary for sorting the infinite words into lexicographic order. We investigate the PATRICIA chains -- the tree-valued Markov chains that arise when successively building the PATRICIA trees for the collection of infinite binary words $Z_1,ldots, Z_n$, $n=1,2,ldots$, where the source words $Z_1, Z_2,ldots$ are independent and have a common diffuse distribution on ${0,1}^infty$. It turns out that the PATRICIA chains share a common collection of backward transition probabilities and that these are the same as those of a chain introduced by R'emy for successively generating uniform random binary trees with larger and larger numbers of leaves. This means that the infinite bridges of any PATRICIA chain (that is, the chains obtained by conditioning a PATRICIA chain on its remote future) coincide with the infinite bridges of the R'emy chain. The infinite bridges of the R'emy chain are characterized concretely in Evans, Gr\"ubel, and Wakolbinger 2017 and we recall that characterization here while adding some details and clarifications.","PeriodicalId":163241,"journal":{"name":"Genealogies of Interacting Particle Systems","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126708115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Coexistence and Duality in Competing Species Models","authors":"Yu-Ting Chen, Matthias Hammer","doi":"10.1142/9789811206092_0001","DOIUrl":"https://doi.org/10.1142/9789811206092_0001","url":null,"abstract":"We discuss some stochastic spatial generalizations of the Lotka--Volterra model for competing species. The generalizations take the forms of spin systems on general discrete sets and interacting diffusions on integer lattices. Methods for proving coexistence in these generalizations and some related open questions are discussed. We use duality as the central point of view. It relates coexistence of the models to survival of their dual processes.","PeriodicalId":163241,"journal":{"name":"Genealogies of Interacting Particle Systems","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115357485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Algebraic Approach to Duality: An Introduction","authors":"A. Sturm, J. Swart, F. Vollering","doi":"10.1142/9789811206092_0003","DOIUrl":"https://doi.org/10.1142/9789811206092_0003","url":null,"abstract":"This survey article gives an elementary introduction to the algebraic approach to Markov process duality, as opposed to the pathwise approach. In the algebraic approach, a Markov generator is written as the sum of products of simpler operators, which each have a dual with respect to some duality function. We discuss at length the recent suggestion by Giardin`a, Redig, and others, that it may be a good idea to choose these simpler operators in such a way that they form an irreducible representation of some known Lie algebra. In particular, we collect the necessary background on representations of Lie algebras that is crucial for this approach. We also discuss older work by Lloyd and Sudbury on duality functions of product form and the relation between intertwining and duality.","PeriodicalId":163241,"journal":{"name":"Genealogies of Interacting Particle Systems","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121722983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Collision Times of Random Walks and Applications to the Brownian Web","authors":"D. Coupier, K. Saha, A. Sarkar, V. Tran","doi":"10.1142/9789811206092_0007","DOIUrl":"https://doi.org/10.1142/9789811206092_0007","url":null,"abstract":"Convergence of directed forests, spanning on random subsets of lattices or on point processes, towards the Brownian web has made the subject of an abundant literature, a large part of which relies on a criterion proposed by Fontes Isopi Newman and Ravishankar (2004). One of their convergence condition, called (B2), roughly states that the probability that the first collision time of three paths, crossing a small segment of length $varepsilon$, bigger than $t (>0)$ is of small order of $varepsilon$, i.e., $o(varepsilon)$. Condition (B2) is often verified by applying an FKG type correlation inequality together with a coalescing time tail estimate for two paths. For many models where paths have complex interactions, it is hard to establish FKG type inequalities. In this paper, we show that for a non-crossing path model, with some homogeneity and Markovian properties, a suitable upper bound on expected first collision time for three paths can be obtained directly using Lyapunov functions and that provides an alternate verification of Condition (B2). We further show that in case of independent simple symmetric one dimensional random walks or in case of independent Brownian motions the expected value can be computed explicitly. \u0000We apply this alternate method of verification of (B2) to several models in the basin of attraction of the Brownian web studied earlier in the literature.","PeriodicalId":163241,"journal":{"name":"Genealogies of Interacting Particle Systems","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116888171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}