👉 In mathematics, a subscheme is an algebraic variety that can be written as a union of simpler varieties. A subvariety is an algebraic set defined by a polynomial equation with coefficients in some field. Subvarieties are fundamental concepts in algebraic geometry and are used to construct the structure sheaf on schemes. For example, consider the complex plane C^n (where n > 1) as a subscheme of itself, which can be written as the union of two copies of C
