Bonus #artAdventCalendar: Happy birthday to #mathematician Virginia Ragsdale (1870-1945). The Ragsdale conjecture, made in her 1906 dissertation, is amongst the earliest & most famous on the #topology of real & algebraic curves, which stimulated a lot of 20th century research & was not disproved until ‘79. A correct upper bound has yet to be found. In her dissertation she tackles the 16th of David Hilbert’s famous 23 unsolved problems in mathematics 🧵