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1.
The free groups of exponent eight are shown to differ from thoseof sufficiently large exponent in the nature of their finitesubgroups. 相似文献
2.
Cardy's formula for some dependent percolation models 总被引:2,自引:0,他引:2
F. Camia C. M. Newman V. Sidoravicius 《Bulletin of the Brazilian Mathematical Society》2002,33(2):147-156
We prove Cardy's formula for rectangular crossing probabilities in dependent site percolation models that arise from a deterministic cellular automaton with a random initial state. The cellular automaton
corresponds to the zero-temperature case of Domany's stochastic Ising ferromagnet on the hexagonal lattice (with alternating
updates of two sublattices) [7]; it may also be realized on the triangular lattice 𝕋 with flips when a site disagrees with
six, five and sometimes four of its six neighbors.
Received: 24 December 2001 相似文献
3.
J. W. Lee Y. Takase B. A. Newman J. I. Scheinbeim 《Journal of Polymer Science.Polymer Physics》1991,29(3):273-277
Cold-drawn Nylon-11 films, which were prepared by stretching the melt-quenched films to a draw ratio of 2.8: 1 at room temperature, were found to exhibit an electric displacement versus electric field hysteresis loop. The results confirmed that the Nylon-11 film exhibited ferroelectric behavior at or below room temperature. The coercive fields were 65, 98, 125, 160, and 215 MV/m at 20, 0, ?20, ?40, and ?60°C and the remanent polarization at ?20°C (where there was considerably less dc conduction) was 56 mC/m2. Switching of the polarization was almost completed within 20 ms. 相似文献
4.
5.
We rigorously establish the existence of an intermediate ordered phase in one-dimensional 1/|x–y|2 percolation, Ising and Potts models. The Ising model truncated two-point function has a power law decay exponent which ranges from its low (and high) temperature value of two down to zero as the inverse temperature and nearest neighbor coupling vary. Similar results are obtained for percolation and Potts models.Alfred P. Sloan Research Fellow. Research supported in part by NSF Grants No. PHY-8706420 and PHY-8645122Research supported in part by NSF Grant No. DMS-8514834 and AFOSR Contract F49620-86-C0130 at the Arizona Center for Math. Sciences 相似文献
6.
7.
Richard P. A. C. Newman 《Communications in Mathematical Physics》1989,123(1):17-52
According to a standard definition of Penrose, a space-time admitting well-defined future and past null infinitiesI
+ andI
– is asymptotically simple if it has no closed timelike curves, and all its endless null geodesics originate fromI
– and terminate atI
+. The global structure of such space-times has previously been successfully investigated only in the presence of additional constraints. The present paper deals with the general case. It is shown thatI
+ is diffeomorphic to the complement of a point in some contractible open 3-manifold, the strongly causal regionI
0
+
ofI
+ is diffeomorphic to
, and every compact connected spacelike 2-surface inI
+ is contained inI
0
+
and is a strong deformation retract of bothI
0
+
andI
+. Moreover the space-time must be globally hyperbolic with Cauchy surfaces which, subject to the truth of the Poincaré conjecture, are diffeomorphic to 3. 相似文献
8.
9.
We present a new formulation of a class of growth models-those which evolve according to an exclusion process. This formulation is based upon a transformation of the probability distribution function which involves Grassmann variables. This method is very general and enables one to derive an exact stochastic differential equation for the model of interest. We describe this method using the traffic model as an example. 相似文献
10.