WEYL'S CIRCLE AND POINT FOR TWO-PARAMETRIC SYSTEM OF STRUM-LIOVILLE DIFFERENTIAL EQUATION

We introduce analogues of Weyl’s circumferences and circles for the system of equations [1] with two parameters. It is proved that the deficiency index of the two-parameter system (1) in the singular end ( , ) b  b1 b2 is not less than one. If one of two-parametric equations (1) has the case of limit circumference, then the deficiency index of the problem (1) is not less than two. But if both of the equations of the two-parameter system (1) has the case of limit circumferences, then the deficiency index of the problem (1) equals four.