Limit‐point/limit‐circle classification for Hain–Lüst type equations

Hain–Lüst equations appear in magnetohydrodynamics. They are Sturm–Liouville equations with coefficients depending rationally on the eigenvalue parameter. In this paper such equations are connected with a 2 × 2 system of differential equations, where the dependence on the eigenvalue parameter is linear. By means of this connection Weyl's fundamental limit‐point/limit‐circle classification is extended to a general setting of Hain–Lüst‐type equations.