• 제목/요약/키워드: generalized convexity

검색결과 43건 처리시간 0.024초

GENERALIZED CLOSE-TO-CONVEX FUNCTIONS

  • NOOR, KHALIDA INAYAT
    • 호남수학학술지
    • /
    • 제17권1호
    • /
    • pp.97-106
    • /
    • 1995
  • We introduce a new class of analytic functions in the unit disk which generalizes the concepts of close-to-convexity and of bounded boundary rotation, and study its various properties including its connection with other classes of analytic and univalent functions.

  • PDF

A FIXED POINT THEOREM REVISITED

  • Kirk, W.A.;Kang, B.G.
    • 대한수학회지
    • /
    • 제34권2호
    • /
    • pp.285-291
    • /
    • 1997
  • In this paper, we obtain an abstract formulation of a fixed point theorem for nonexpansive mappings. Our theorem is a non-metric version of Kirk's original theorem.

  • PDF

ON NONLINEAR PROGRAMMING WITH SUPPORT FUNCTIONS

  • Husain, I.;Abha;Jabeen, Z.
    • Journal of applied mathematics & informatics
    • /
    • 제10권1_2호
    • /
    • pp.83-99
    • /
    • 2002
  • Optimality conditions are derived for a nonlinear program in which a support function appears in the objective as well as in each constraint function. Wolfe and Mond-Weir type duals to this program are presented and various duality results are established under suitable convexity and generalized convexity assumptions. Special cases that often occur in the literature are those in which a support function is the square root of a positive semi- definite quadratic form or an Lp norm. It is pointed out that these special cases can easily be generated from our results.

A CLASS OF COMPLETELY MONOTONIC FUNCTIONS INVOLVING DIVIDED DIFFERENCES OF THE PSI AND TRI-GAMMA FUNCTIONS AND SOME APPLICATIONS

  • Guo, Bai-Ni;Qi, Feng
    • 대한수학회지
    • /
    • 제48권3호
    • /
    • pp.655-667
    • /
    • 2011
  • A class of functions involving divided differences of the psi and tri-gamma functions and originating from Kershaw's double inequality are proved to be completely monotonic. As applications of these results, the monotonicity and convexity of a function involving the ratio of two gamma functions and originating from the establishment of the best upper and lower bounds in Kershaw's double inequality are derived, two sharp double inequalities involving ratios of double factorials are recovered, the probability integral or error function is estimated, a double inequality for ratio of the volumes of the unit balls in $\mathbb{R}^{n-1}$ and $\mathbb{R}^n$ respectively is deduced, and a symmetrical upper and lower bounds for the gamma function in terms of the psi function is generalized.

GEOMETRIC PROPERTIES ON (j, k)-SYMMETRIC FUNCTIONS RELATED TO STARLIKE AND CONVEX FUNCTION

  • Gochhayat, Priyabrat;Prajapati, Anuja
    • 대한수학회논문집
    • /
    • 제37권2호
    • /
    • pp.455-472
    • /
    • 2022
  • For j = 0, 1, 2,…, k - 1; k ≥ 2; and - 1 ≤ B < A ≤ 1, we have introduced the functions classes denoted by ST[j,k](A, B) and K[j,k](A, B), respectively, called the generalized (j, k)-symmetric starlike and convex functions. We first proved the sharp bounds on |f(z)| and |f'(z)|. Various radii related problems, such as radius of (j, k)-symmetric starlikeness, convexity, strongly starlikeness and parabolic starlikeness are determined. The quantity |a23 - a5|, which provide the initial bound on Zalcman functional is obtained for the functions in the family ST[j,k]. Furthermore, the sharp pre-Schwarzian norm is also established for the case when f is a member of K[j,k](α) for all 0 ≤ α < 1.

MONOTONICITY PROPERTIES OF THE GENERALIZED STRUVE FUNCTIONS

  • Ali, Rosihan M.;Mondal, Saiful R.;Nisar, Kottakkaran S.
    • 대한수학회지
    • /
    • 제54권2호
    • /
    • pp.575-598
    • /
    • 2017
  • This paper introduces and studies a generalization of the classical Struve function of order p given by $$_aS_{p,c}(x):=\sum\limits_{k=0}^{\infty}\frac{(-c)^k}{{\Gamma}(ak+p+\frac{3}{2}){\Gamma}(k+\frac{3}{2})}(\frac{x}{2})^{2k+p+1}$$. Representation formulae are derived for $_aS_{p,c}$. Further the function $_aS_{p,c}$ is shown to be a solution of an (a + 1)-order differential equation. Monotonicity and log-convexity properties for the generalized Struve function $_aS_{p,c}$ are investigated, particulary for the case c = -1. As a consequence, $Tur{\acute{a}}n$-type inequalities are established. For a = 2 and c = -1, dominant and subordinant functions are obtained for the Struve function $_2S_{p,-1}$.

COMPLETION OF FUNDAMENTAL TOPOLOGICAL VECTOR SPACES

  • ANSARI-PIRI, E.
    • 호남수학학술지
    • /
    • 제26권1호
    • /
    • pp.77-83
    • /
    • 2004
  • A class of topological algebras, which we call it a fundamental one, has already been introduced generalizing the famous Cohen factorization theorem to more general topological algebras. To prove the generalized versions of Cohen's theorem to locally multilplicatively convex algebras, and finally to fundamental topological algebras, the completness of the background spaces is one of the main conditions. The local convexity of the completion of a locally convex space is a well known fact and here we have a discussion on the completness of fundamental metrizable topological vector spaces.

  • PDF