yán / jiū / yuán / bǎ / zhè / ge / fāng / chéng / kàn / zuò / dìng / yì / zài / yǒu / lǐ / shù / yù / shàng / de / wèn / tí

研究员把这个方程看作定义在有理数域上的问题。

The researcher treated this equation as a problem defined over the field of rational numbers.