Ring extension

A ring extension is the embedding of a ring $𝑅$ in a larger ring $𝑇$ , ring i.e. a Ring monomorphism $𝑅 ↪ 𝑇$ or equivalently $𝑅$ is a subring of $𝑇$ . We write $𝑇 : 𝑅$ , and $𝑇$ is thence called an extension ring of $𝑅$ . An Adjunction of a ring is a particularly pertinent way of extending rings.