Article
Keywords:
self-adjoint differential equation; oscillation and nonoscillation criteria; variational method; conditional oscillation.
Summary:
Oscillation and nonoscillation criteria for the self-adjoint linear differential equation \[ (t^\alpha y^{\prime \prime })^{\prime \prime }-\frac{\gamma _{2,\alpha }}{t^{4-\alpha }}y=q(t)y,\quad \alpha \notin \lbrace 1, 3\rbrace \,, \] where \[ \gamma _{2,\alpha }=\frac{(\alpha -1)^2(\alpha -3)^2}{16}\] and $q$ is a real and continuous function, are established. It is proved, using these criteria, that the equation \[\left(t^\alpha y^{\prime \prime }\right)^{\prime \prime }-\left(\frac{\gamma _{2,\alpha }}{t^{4-\alpha }} + \frac{\gamma }{t^{4-\alpha }\ln ^2 t}\right)y = 0\] is nonoscillatory if and only if $\gamma \le \frac{\alpha ^2-4\alpha +5}{8}$.
References:
[1] Coppel W. A.:
Disconjugacy. Lectures Notes in Math., No. 220, Springer Verlag, Berlin-Heidelberg 1971.
MR 0460785 |
Zbl 0224.34003
[2] Došlý O.:
Nehari-type oscillation criteria for self-adjoint linear equations. J. Math. Anal. Appl. 182 (1994), 69–89.
MR 1265883
[3] Došlý O.:
Oscillatory properties of fourth order Sturm-Liouville differential equations. Acta Univ. Palack. Olomuc. Fac. Rerum. Natur. Math. 41 (2002), 49–59.
MR 1967340 |
Zbl 1055.34065
[4] Došlý O., Osička J.:
Oscillation and nonoscillation of higher order self-adjoint differential equations. Czechoslovak Math. J. 52 (127) (2002), 833-849.
MR 1940063
[5] Došlý O., Osička J.:
Oscillatory properties of higher order Sturm-Liouville differential equations. Studies Univ. Žilina, Math. Ser. 15 (2002), 25–40.
MR 1980760 |
Zbl 1062.34034
[6] Glazman I. M.: Direct Methods of Qualitative Anylysis of Singular Differential Operators. Davey, Jerusalem 1965.
[7] Hinton D. B., Lewis R. T.:
Discrete spectra criteria for singular differential operators with middle terms. Math. Proc. Cambridge Philos. Soc. 77 (1975), 337–347.
MR 0367358 |
Zbl 0298.34018