The Monotone Iterative Roots of a Class of Self-Mappings on the Interval

Let I = [0,1], 0 < a < b < 1. Let Φab ≡ {F ∈ C0(I): both F|[0,a] and F|[b, 1] are strictly increasing, and F|[a, b] is constant }. In this paper we discuss necessary and sufficient conditions for F ∈Φab to have monotone iterative roots.

Real polynomial iterative roots in the case of nonmonotonicity height ≥ 2

It is known that a strictly piecewise monotone function with nonmonotonicity height ≥ 2 on a compact interval has no iterative roots of order greater than the number of forts. An open question is: Does it have iterative roots of order less than or equal to the number of forts? An answer was given recently in the case of "equal to". Since many theories of resultant and algebraic varieties can be applied to computation of polynomials, a special class of strictly piecewise monotone functions, in this paper we investigate the question in the case of "less than" for polynomials. For this purpose we extend the question from a compact interval to the whole real line and give a procedure of computation for real polynomial iterative roots. Applying the procedure together with the theory of discriminants, we find all real quartic polynomials of non-monotonicity height 2 which have quadratic polynomial iterative roots of order 2 and answer the question.

Conjugacy between piecewise monotonic functions and their iterative roots

It was proved that all continuous functions are topologically conjugate to their continuous iterative roots in monotonic cases. An interesting problem reads: Does the same conclusion hold in non-monotonic cases?We give a negative answer to the problem by presenting a necessary condition for the topological conjugacy,which helps us construct counter examples. We also give a sufficient condition as well as a method of constructing the topological conjugacy.

On the colocation iterative solution model and algorithm for gravity anomaly

An effective method of random approach of gravity anomaly is collocation. To improve the reliability of collocation root, it is crucial to improve the reliability of covariance function of gravity anomaly. In this paper, a set of theoretical models of iterative fitting covariance function and predicting gravity anomaly is established. Through practical calculation, it shows that after finite iterative collocating, they do work well.

AN APPLICATION OF HARDY-BOEDEWADT'S THEOREM TO ITERATED FUNCTIONAL EQUATIONS

In this paper an iterated functional equation of polynomial type which does not possess the firt order iterative term g(x) is to be discussed. The difficulties resulted from loss of the first order term are overcome by utilization of Hardy-Boedewadt's theorem.

Method of Characteristic for Functional Equations in Polynomial Form

Properties of continuous solutions of a second order polynomial-like iterated functional equation are given by considering its characteristic.A useful method to discuss the general case is described indeed in this procedure.