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Invariants for reducible systems of meromorphic differential equations

Published online by Cambridge University Press:  20 January 2009

W. Balser
Affiliation:
Universität UlmD. 7900 UlmWest Germany
W. B. Jurkat
Affiliation:
University of Wisconsin-MilwaukeeMilwaukee Wisconsin 53261
D. A. Lutz
Affiliation:
Syracuse UniversityNew York 13210
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With differential equations in the neighbourhood of an irregular singular point, it sometimes happens that formal solutions may converge. For example, this occurs for Bessel's equation at∞ when the parameter is half of an odd integer. In addition, there are some classical theorems of Perron and Lettenmeyer which give sufficient conditions for the existence of linearly independent analytic solutions at (generally) an irregular singular point. Using the principle of reduction of order, such a solution may be used to transform the differential equation into one whose coefficient matrix is triangularly blocked with an (n – 1) and 1-block on the diagonal. The solutions of the given differential equation can thus be obtained by solving a lower dimensional differential equation plus quadrature.

Type
Research Article
Copyright
Copyright © Edinburgh Mathematical Society 1980

References

REFERENCES

(1, 2)Balser, W., Jurkat, W. B., and Lutz, D. A., A general theory of invariants for meromorphic differential equations, Parts I & II, Funk. Ekvac. (to appear).Google Scholar
(3)Balser, W., Jurkat, W. B. and Lutz, D. A., Birkhorf invariants and Stokes' multipliers for meromorphic linear differential equations, J. Math. Anal. Appl. 71 (1979), 4894.CrossRefGoogle Scholar
(4)Gantmacher, F. R., Theory of Matrices, vol. I&II (Chelsea, New York, 1959).Google Scholar
(5)Hall, L. M., The mumber of analytic solutions of a singular differential system, preprint.Google Scholar
(6)Jurkat, W. B., Meromorphe Differentialgleichungen (Lecture Notes in Mathematics No 637, Springer Verlag, Berlin, Heidelberg, New York, 1978).CrossRefGoogle Scholar
(7)Jurkat, W. B., Lutz, D. A. and Peyerimhoff, A., Birkhoff invariants and effective calculations for meromorphic linear differential equations, Part I, J. Math.Anal. Appl. 53 (1976), 438470; Part II, Houston J. Math. 2 (1976), 207–238.CrossRefGoogle Scholar
(8)Malgrange, B., Sur les points singuliers des équations differentielles, L'Enseignement Mathématiques, vol. XX, 12 (1974), 147176.Google Scholar