Renku of the formats most commonly used in writing renku Renku , or , is a Japanese form of popular collaborative linked verse poetry. It is a development of the older Japanese poetic tradition of "ushin" renga, or orthodox collaborative linked verse. At renku gatherings participating poets take turns providing alternating verses of 17 and 14 morae. Initially "haikai no renga" distinguished itself through vulgarity and coarseness of wit, before growing into a legitimate artistic tradition, and eventually giving birth to the haiku form of Japanese poetry. The term "renku" gained currency after 1904, when Kyoshi Takahama started to use it.
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