Greedy lattice animals: negative values and unconstrained maxima
Dembo, Amir ; Gandolfi, Alberto ; Kesten, Harry
Ann. Probab., Tome 29 (2001) no. 1, p. 205-241 / Harvested from Project Euclid
Let $\{X_v, v \in \mathbb{Z}^d\}$ be i.i.d. random variables, and $S(\xi) = \sum_{v \in \xi} X_v$ be the weight of a lattice animal $\xi$. Let $N_n = \max\{S(\xi) : |\xi| = n$ \text{and $\xi$ contains the origin}\}$ and $G_n = \max\{S(\xi) : \xi \subseteq [-n,n]^d\}$ . We show that, regardless of the negative tail of the distribution of $X_v$ , if $\mathbf{E}( X_v^+)^d (\log^+ X_v^+))^{d+a} < + \infty$ for some $a>0$, then first, $\lim_n n^{-1} N_n = N exists, is finite and constant a.e.; and, second, there is a transition in the asymptotic behavior of $G_n$ depending on the sign of $N$: if $N > 0$ then $G_n \approx n^d$, and if $N < 0$ then $G_n \le cn$, for some $c > 0$. The exact behavior of $G_n$ in this last case depends on the positive tail of the distribution of $X_v$; we show that if it is nontrivial and has exponential moments, then $G_n \approx \log n$, with a transition from $G_n \approx n^d$ occurring in general not as predicted by large deviations estimates. Finally, if $x^d(1 - F(x)) \to \infty$as $x \to \infty$, then no transition takes place.
Publié le : 2001-02-14
Classification:  Optimization,  lattice animals,  percolation,  60G50,  60K35,  60F10,  82B41
@article{1008956328,
     author = {Dembo, Amir and Gandolfi, Alberto and Kesten, Harry},
     title = {Greedy lattice animals: negative values and unconstrained
		 maxima},
     journal = {Ann. Probab.},
     volume = {29},
     number = {1},
     year = {2001},
     pages = { 205-241},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1008956328}
}
Dembo, Amir; Gandolfi, Alberto; Kesten, Harry. Greedy lattice animals: negative values and unconstrained
		 maxima. Ann. Probab., Tome 29 (2001) no. 1, pp.  205-241. http://gdmltest.u-ga.fr/item/1008956328/