Biodiversity of Catalytic Super-Brownian Motion
نویسندگان
چکیده
In this paper we investigate the structure of the equilibrium state of three{dimensional catalytic super-Brownian motion where the catalyst is itself a classical super-Brownian motion. We show that the reactant has an in nite local biodiversity or genetic abundance. This contrasts the nite local biodiversity of the equilibrium of classical super-Brownian motion. Another question we address is that of extinction of the reactant in nite time or in the long{time limit in dimensions d = 2; 3. Here we assume that the catalyst starts in the Lebesgue measure and the reactant starts in a nite measure. We show that there is extinction in the long{time limit if d = 2 or 3. There is, however, no nite time extinction if d = 3 (for d = 2 this problem is left open). This complements a result of Dawson and Fleischmann (1997a) for d = 1 and again contrasts the behaviour of classical super-Brownian motion. As a key tool for both problems we show that in d = 3 the reactant matter propagates everywhere in space immediately.
منابع مشابه
Persistence of a Two-dimensional Super-brownian Motion in a Catalytic Medium
The super-Brownian motion X % in a super-Brownian medium % constructed in DF96a] is known to be persistent (no loss of expected mass in the longtime behaviour) in dimensions one ((DF96a]) and three ((DF96b]). Here we ll the gap in showing that persistence holds also in the critical dimension two. The key to this result is that in any dimension (d 3); given the catalyst, the variance of the proc...
متن کاملA Super-brownian Motion with a Locally Innnite Catalytic Mass
A super-Brownian motion X in IR with \hyperbolic" branching rate %2(b) = 1=b 2 , b 2 IR; is constructed, which symbolically could be described by the formal stochastic equation dXt = 1 2 Xt dt + p 2%2Xt dWt ; t > 0; (1) (with a space-time white noise dW). Starting at X0 = a ; a 6 = 0; this superprocess X will never hit the catalytic center: There is an increasing sequence of Brownian stopping t...
متن کاملConvergence to a Non-trivial Equilibrium for Two-dimensional Catalytic Super-brownian Motion Contents 1 Introduction 1 2 Preparations 5 2.1 Catalytic Sbm {lipschitz Continuity Of
In contrast to the classical super-Brownian motion (SBM), the SBM (X % t) t0 in a super-Brownian medium % (constructed in DF96a]) is known to be persistent in all three dimensions of its non-trivial existence: The full intensity is carried also by all longtime limit points ((DF96a, DF96b, EF96]). Uniqueness of the accumulation point, however, has been shown so far only in dimensions d = 1 and d...
متن کاملSmooth Density Eld of Catalytic Super-brownian Motion
Given an (ordinary) super-Brownian motion (SBM) % on R d of dimension d = 2; 3; we consider a (catalytic) SBM X % on R d with \local branching rates" %s(dx). We show that X % t is absolutely continuous with a density function % t ; say. Moreover, there exists a version of the map (t; z) 7 ! % t (z) which is C 1 and solves the heat equation oo the catalyst %, more precisely, oo the (zero set of)...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 1999