Haiku in English founded National Haiku Writing Month, also known as NaHaiWriMo. It has been held in February of each year, starting in 2011, with the objective to write at least one haiku per day all month long—"the shortest month of the year for the shortest genre of poetry," according to Welch. Although the vast majority of haiku published in English are three lines long, variants also occur. The most common variation from the three-line standard is one line, sometimes called a "monoku". It emerged from being more than an occasional exception during the late 1970s. The one-line form, based on an analogy
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