M-curves of degree 9: New prohibitions (Q1089400)

The paper contains some new results about nonexistence of singular plane real algebraic curves F of degree 9 with maximal (for the given degree \(9)\) number of connected components and prescribed topology of the pair \(({\mathbb{R}}P^ 2,F)\). There are 1723 a priori possible topology types of the pair \(({\mathbb{R}}P^ 2,F)\). The author proves that 420 of them are excluded, in addition to 52 types excluded before (by Th. Fiedler).