Poetry Japanese formal poetry (which was generally referred to as "waka"), and was used more heavily to explore personal rather than public themes. By the tenth century, tanka had become the dominant form of Japanese poetry, to the point where the originally general term "waka" ("Japanese poetry") came to be used exclusively for tanka. Tanka are still widely written today. Haiku is a popular form of unrhymed Japanese poetry, which evolved in the 17th century from the "hokku", or opening verse of a renku. Generally written in a single vertical line, the haiku contains three sections totalling 17 "onji", structured in
Invariant of a binary form for the ring of covariants. showed that the ring of invariants of a degree 8 form is generated by 9 invariants of degrees 2, 3, 4, 5, 6, 7, 8, 9, 10, and the ring of covariants is generated by 69 covariants. August von Gall () and confirmed the generators for the ring of invariants and showed that the ideal of relations between them is generated by elements of degrees 16, 17, 18, 19, 20. showed that the algebra of invariants of a degree 9 form is generated by 92 invariants. Cröni, Hagedorn, and Brouwer computed 476 covariants, and Lercier