Semi-invariants and relative invariants for homogeneous linear differential equations (Q1260845)

In his previous paper [J. Differ. Equations 80, 107-153 (1989; Zbl 0693.34005); 100, 379-404 (1992)] the author has presented relative invariants for homogeneous linear differential equations of order \(m\) in the complex domain as a polynomial combination of semi-invariants of the first kind. In this paper semi-invariants of the second kind with similar properties are introduced. Similar problems in the real domain have been solved by \textit{Z. Husty} [Czech. Math. J. 15(90), 479-502 (1965; Zbl 0173.341); 16(91), 1-13 (1966; Zbl 0173.341); 16(91), 161-185 (1966)] and by \textit{F. Neumann} [Global properties of linear ordinary differential equations, Academia-Praha (1991)].