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961.
962.
Motivated by issues arising in population dynamics, we consider the problem of iterating a given analytic function a number of times. We use the celebrated technique known as Carleman linearization that turns (for a certain class of functions) this problem into simply taking the power of a real number. We expand this method, showing in particular that it can be used for population models with immigration, and we also apply it to the famous logistic map. We also are able to give a number of results for the invariant density of this map, some being related to the Carleman linearization. 相似文献
963.
The Ram–Yip formula for Macdonald polynomials (at t = 0) provides a statistic which we call charge. In types A and C it can be defined on tensor products of Kashiwara–Nakashima single column crystals. In this paper we prove that the charge is equal to the (negative of the) energy function on affine crystals. The algorithm for computing charge is much simpler and can be more efficiently computed than the recursive definition of energy in terms of the combinatorial R-matrix. 相似文献
964.
Marwan Awartani Mary W. Gray 《International Journal of Mathematical Education in Science & Technology》2013,44(2):317-320
Results of mathematics testing of 14‐year‐olds and college freshmen in the West Bank indicate more substantial variation on the basis of cultural factors than on the basis of gender. In particular, no significant difference in the mathematical abilities of men and women appeared in the college group. 相似文献
965.
《Journal of Pure and Applied Algebra》2023,227(4):107256
We develop a duality for operations on nested pairs of modules that generalizes the duality between absolute interior operations and residual closure operations from [5], extending our previous results to the expanded context. We apply this duality in particular to integral and basically full closures and their respective cores to obtain integral and basically empty interiors and their respective hulls. We also dualize some of the known formulas for the core of an ideal to obtain formulas for the hull of a submodule of the injective hull of the residue field. The article concludes with illustrative examples in a numerical semigroup ring. 相似文献
966.
《Communications in Nonlinear Science & Numerical Simulation》2011,16(11):4438-4450
In this paper we study an SEIR epidemic model with saturated recovery rate. A backward bifurcation leading to bistability possibly occurs, and global dynamics are shown by compound matrices and geometric approaches. Numerical simulations are presented to illustrate the results. 相似文献
967.
Aleksandra Zapadinskaya 《Central European Journal of Mathematics》2011,9(2):356-363
We prove a dimension compression estimate for homeomorphic mappings of exponentially integrable distortion via a modulus of
continuity result by D. Herron and P. Koskela [Mappings of finite distortion: gauge dimension of generalized quasicircles,
Illinois J. Math., 2003, 47(4), 1243–1259]. The essential sharpness of our estimate is demonstrated by an example. 相似文献
968.
969.
Let G be a connected graph. The resistance distance between any two vertices of G is defined as the net effective resistance between them if each edge of G is replaced by a unit resistor. The Kirchhoff index is the sum of resistance distances between all pairs of vertices in G. Zhou and Trinajstić (Chem Phys Lett 455(1–3):120–123, 2008) obtained a Nordhaus-Gaddum-type result for the Kirchhoff index by obtaining lower and upper bounds for the sum of the Kirchhoff
index of a graph and its complement. In this paper, by making use of the Cauchy-Schwarz inequality, spectral graph theory
and Foster’s formula, we give better lower and upper bounds. In particular, the lower bound turns out to be tight. Furthermore,
we establish lower and upper bounds on the product of the Kirchhoff index of a graph and its complement. 相似文献
970.
In this paper we discuss how partial knowledge of the density of states for a model can be used to give good approximations
of the energy distributions in a given temperature range. From these distributions one can then obtain the statistical moments
corresponding to e.g. the internal energy and the specific heat. These questions have gained interest apropos of several recent
methods for estimating the density of states of spin models. As a worked example we finally apply these methods to the 3-state
Potts model for cubic lattices of linear order up to 128. We give estimates of e.g. latent heat and critical temperature,
as well as the micro-canonical properties of interest.
相似文献