Haiku in English popular in English-language schools as a way to encourage the appreciation and writing of poetry. "Haiku" is a term sometimes loosely applied to any short, impressionistic poem, but there are certain characteristics that are commonly associated with the genre: Some additional traits are especially associated with English-language haiku (as opposed to Japanese-language haiku): Arguably, the first successful haiku in English was "In a Station of the Metro" by Ezra Pound, published in 1913. During the Imagist period, a number of mainstream poets, including Pound, wrote what they called "hokku", usually in a five-six-four syllable pattern. American poet Amy Lowell published
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