Li Ye (mathematician)

[1][3][4][5][6][7] Along with the 4th-century Chinese astronomer Yu Xi, Li Ye proposed the idea of a spherical Earth instead of a flat one before the advances of European science in the 17th century.

Li passed the civil service examination in 1230 at the age of 38, and was administrative prefect of Jun prefecture in Henan province until the Mongol invasion in 1233.

[1] He spent his final years teaching at his home near Feng Lung mountain in Yuan, Hebei.

[1] Ceyuan haijing (Sea mirror of circle measurements) is a collection of 170 problems, all related to the same example of a circular city wall inscribed in a right triangle and a square.

Yigu yanduan consists of three volumes dedicated to solving geometrical problems on two tracks, through Tian yuan shu and geometry.

[11] The huntian (渾天) theory of the celestial sphere stipulated that the earth was flat and square, while the heavens were spherical in shape, along with celestial bodies such as the sun and moon (described by 1st-century AD polymathic scientist and statesman Zhang Heng like a crossbow bullet and ball, respectively).

[12] However, the idea of a flat earth was criticized by the Jin dynasty astronomer Yu Xi (fl.

[15] However, the idea of a spherical earth was not accepted in mainstream Chinese science and cartography until the 17th century during the late Ming and early Qing periods, with the advent of evidence of European circumnavigation of the globe.