[[Reducibility of modules]] # Indecomposable module A (left) $R$-[[module]] is **indecomposable** iff it not the [[Direct sum of modules|direct sum]] of two nontrivial [[Submodule|submodules]], #m/def/module i.e. it is not a [[decomposable module]]. Note this does not imply $M$ is a [[simple module]]. # --- #state/develop | #lang/en | #SemBr