Improvements on the Leighton oscillation theorem for second-order dynamic equations


Zafer A., DOĞRU AKGÖL S.

Mathematica Slovaca, cilt.75, sa.1, ss.169-178, 2025 (SCI-Expanded, Scopus) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 75 Sayı: 1
  • Basım Tarihi: 2025
  • Doi Numarası: 10.1515/ms-2025-0013
  • Dergi Adı: Mathematica Slovaca
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, MathSciNet, zbMATH
  • Sayfa Sayıları: ss.169-178
  • Anahtar Kelimeler: canonical type, dynamic equation, noncanonical type, oscillation, Second-order, time scales
  • Çukurova Üniversitesi Adresli: Evet

Özet

The time scales version of the Leighton oscillation theorem states that if (Formula presented) where a and p are rd-continuous with a(t) > 0 for t ≥ t0, then every solution of the second-order self-adjoint dynamic equation (Formula presented) is oscillatory. The theorem turns into the famous Leighton oscillation theorem when the time scale is taken as the set of real numbers, and its discrete version when the time scale is taken as the set of integers. The divergence of the first improper integral in (∗) means that the dynamic equation is in canonical form. The equation is called noncanonical when the integral is convergent. In this study, we establish an improved version of the Leighton oscillation theorem on time scales that can be applied to both canonical and noncanonical types of dynamic equations. Furthermore, we allow the second improper integral in (∗) to be convergent. In the special case, we derive completely new Leighton-type oscillation theorems for second-order self-adjoint difference equations (Formula presented) where Δ is the forward difference operator, defined by Δxk = xk+1 - xk (the derivative). Examples are given to illustrate the significance of these theorems.