The similarity problem for $J$-nonnegative Sturm-Liouville operators

Illya M. Karabash, Aleksey S. Kostenko, Mark M. Malamud

Sufficient conditions for the similarity of the operator $A:=1/r(x)(-d^2/d{x}^2+q(x))$ with an indefinite weight $r(x)=(\sgn x)|r(x)|$ are obtained. These conditions are formulat…