# Module on Cartesian Product of Ring with Unity is Unitary Module

## Theorem

Let $\struct {R, +_R, \times_R}$ be a ring with unity.

Let $n \in \N_{>0}$.

Let $\struct {R^n, +, \times}_R$ be the $R$-module $R^n$.

Then $\struct {R^n, +, \times}_R$ is a unitary $R$-module.

## Proof 1

This is a special case of Direct Product of Unitary Modules is Unitary Module.

$\blacksquare$

## Proof 2

This is a special case of the Unitary Module of All Mappings is Unitary Module, where $S$ is the set $\closedint 1 n \subset \N_{>0}$.

$\blacksquare$

## Proof 3

This is a special case of a Finite Direct Product of Unitary Modules is Unitary Module where each of the $G_k$ is the $R$-module $R$.

$\blacksquare$