数学物理学报(英文版) ›› 2002, Vol. 22 ›› Issue (1): 56-62.

• 论文 • 上一篇    下一篇

AN OSCILLATION CRITERIA FOR SECOND ORDER FUNCTIONAL EQUATIONS

 申建华, I.P. Stavroulakis   

  1. Department of Mathematics, Hunan Normal University, Changsha 410081, China Department of Mathematics, University of Ioannina 451 10, Ioannina, Greece
  • 出版日期:2002-01-14 发布日期:2002-01-14

AN OSCILLATION CRITERIA FOR SECOND ORDER FUNCTIONAL EQUATIONS

 SHEN Jian-Hua, I.P. Stavroulakis   

  1. Department of Mathematics, Hunan Normal University, Changsha 410081, China Department of Mathematics, University of Ioannina 451 10, Ioannina, Greece
  • Online:2002-01-14 Published:2002-01-14

摘要:

This paper is concerned with the oscillation of second order linear functional equations of the form x(g(t)) = P(t)x(t) + Q(t)x(g2(t)), where P,Q, g : [t0,∞) → R+ =[0,∞) are given real valued functions such that g(t) 6≡ t, limt!1 g(t) = ∞. It is proved here that when 0 ≤ m := liminft!1 Q(t)P(g(t)) ≤ 1/4 all solutions of this equation oscillate if the condition limsup t!1 Q(t)P(g(t)) > 1 + √1 − 4m 2 2 (∗) is satisfied. It should be emphasized that the condition (∗) can not be improved in some sense.

关键词: Oscillation, nonoscillation, functional equations

Abstract:

This paper is concerned with the oscillation of second order linear functional equations of the form x(g(t)) = P(t)x(t) + Q(t)x(g2(t)), where P,Q, g : [t0,∞) → R+ =[0,∞) are given real valued functions such that g(t) 6≡ t, limt!1 g(t) = ∞. It is proved here that when 0 ≤ m := liminft!1 Q(t)P(g(t)) ≤ 1/4 all solutions of this equation oscillate if the condition limsup t!1 Q(t)P(g(t)) > 1 + √1 − 4m 2 2 (∗) is satisfied. It should be emphasized that the condition (∗) can not be improved in some sense.

Key words: Oscillation, nonoscillation, functional equations

中图分类号: 

  • 39B22