Systems-conjugate and focal points of fourth order nonselfadjoint differential equations

Cheng, Sui Sun

doi:10.1090/S0002-9947-1976-0473334-3

Systems-conjugate and focal points of fourth order nonselfadjoint differential equations
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Trans. Amer. Math. Soc. 223 (1976), 155-165 Request permission

Abstract:

Systems-conjugate points have been studied by John Barrett in relation to selfadjoint fourth order differential equations of the form $({p_2}u'')'' + {p_0}u = 0$. This paper extends his results to the general nonselfadjoint fourth order differential equation via a system of second order equations.

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