# Definition:Subfield/Ring

(Redirected from Definition:Subfield of Ring)
Let $\struct {R, +, \circ}$ be a ring with unity.
Let $K$ be a subset of $R$ such that $\struct {K, +, \circ}$ is a field.
Then $\struct {K, +, \circ}$ is a subfield of $\struct {R, +, \circ}$.