Complex sentence: In mathematics, specifically in ring theory, an algebra over a commutative ring is a generalization of the concept of an algebra over a field, where the base field "K" is replaced by a commutative ring "R".
Split into simpler sentences: In mathematics, specifically in ring theory, an algebra over a commutative ring is a generalization of the concept of an algebra over a field. One simply replaces the base field "K" with a commutative ring "R".