Abstract:
In order to introduce the study undertaken in this thesis, let us consider the differential equationz2 (μ 2 - 2μ zm + z2m) d2y/dz2 + z (b0 + b1zm + b2z2m) dy/dz+ (c0 + c1zm + c2z2m) y = 0The variable z and he coefficients μ, bi, ci (i = 0, 1, 2) are regarded as complex and m is an arbitrary positive integer. It is also assumed that b0 + b1u + b2p2 = 0 and that the difference of the two roots of the indicial equation about z = 0 is not congruent to zero modulo m.