Ragsdale conjecture

The Ragsdale conjecture is a mathematical conjecture that concerns the possible arrangements of real algebraic curves embedded in the projective plane. It was proposed by Virginia Ragsdale in her dissertation in 1906 and was disproved in 1979. It has been called "the oldest and most famous conjecture on the topology of real algebraic curves".[1]

  1. ^ Itenberg, Ilya; Oleg, Viro (1996). "Patchworking algebraic curves disproves the ragsdale conjecture". The Mathematical Intelligencer. 18 (4). Springer-Verlag: 19–28. doi:10.1007/BF03026748.