We review the main results of the seminal paper of Widom [2] on asymptotics of or-thogonal and Chebyshev polynomials associated with a set E (i.e., the monic polynomialsof degree at most n that minimize the sup-norm‖Tn‖E), where E is a system of Jordanregions and arcs. Thiran and Detaille [1], considered the Chebyshev polynomials Tn on acircular arc Aα and managed to fin...

where x(t) ∈ D ⊂ Rp and f (x) ∈ R is an unknown function but assumed to be bounded function in x. When the structure of the uncertainty is unknown, function approximation is usually employed to estimate the unknown function. In recent years, neural networks have gained a lot of attention in function approximation theory in connection with adaptive control. Multi-layer neural networks have the c...

We say that a monic polynomial with integer coefficients is polygomial if its each zero obtained by squaring the edge or diagonal of regular n-gon unit circumradius. find connections certain polygomials Morgan-Voyce polynomials and further Chebyshev second kind.

In this paper, we study the generalized Marcum -function where and . Our aim is to extend the results of Corazza and Ferrari (IEEE Trans. Inf. Theory, vol. 48, pp. 3003–3008, 2002) to the generalized Marcum -function in order to deduce some new tight lower and upper bounds. The key tools in our proofs are some monotonicity properties of certain functions involving the modified Bessel function o...

We study the total weight of weighted matchings in segment graphs, which is related to a question concerning generalized Chebyshev polynomials introduced by Vauchassade de Chaumont and Viennot and, more recently, investigated by Kim and Zeng. We prove that weighted matchings with sufficiently large node-weight cannot have equal total weight.

We study generating functions for the number of involutions of length n avoiding (or containing exactly once) 132 and avoiding (or containing exactly once) an arbitrary permutation τ of length k. In several interesting cases these generating functions depend only on k and can be expressed via Chebyshev polynomials of the second kind. In particular, we show that involutions of length n avoiding ...

A partition π of the set [n] = {1, 2, . . . , n} is a collection {B1, B2, . . . , Bk} of nonempty disjoint subsets of [n] (called blocks) whose union equals [n]. In this paper, we find an explicit formula for the generating function for the number of partitions of [n] with exactly k blocks according to the number of peaks (valleys) in terms of Chebyshev polynomials of the second kind. Furthermo...

Is it true that for all integer n > 1 and k ≤ n there exists a prime number in the interval [kn, (k + 1)n]? The case k = 1 is the Bertrand’s postulate which was proved for the first time by P. L. Chebyshev in 1850, and simplified later by P. Erdős in 1932, see [2]. The present paper deals with the case k = 2. A positive answer to the problem for any k ≤ n implies a positive answer to the old pr...

We say that a permutation is a Motzkin permutation if it avoids 132 and there do not exist a <b such that a < b < b+1. We study the distribution of several statistics in Motzkin permutations, including the length of the longest increasing and decreasing subsequences and the number of rises and descents. We also enumerate Motzkin permutations with additional restrictions, and study the distribut...

In this paper, we present the constrained Jacobi polynomial which is equal to the constrained Chebyshev polynomial up to constant multiplication. For degree n = 4, 5, we find the constrained Jacobi polynomial, and for n ≥ 6, we present the normalized constrained Jacobi polynomial which is similar to the constrained Chebyshev polynomial.