Baer criterion
= Baer criterion
{c}
This criterion characterizes an <injective module> using extension from ideals. A left $R$-module is injective exactly when every homomorphism from a left ideal of $R$ extends to a homomorphism from $R$.
= Baer criterion
{c}
This criterion characterizes an <injective module> using extension from ideals. A left $R$-module is injective exactly when every homomorphism from a left ideal of $R$ extends to a homomorphism from $R$.