Definition:Scalar Ring
Definition
Let $\struct {S, *_1, *_2, \ldots, *_n, \circ}_R$ be an $R$-algebraic structure with $n$ operations, where:
- $\struct {R, +_R, \times_R}$ is a ring
- $\struct {S, *_1, *_2, \ldots, *_n}$ is an algebraic structure with $n$ operations
- $\circ: R \times S \to S$ is a binary operation.
Then the ring $\struct {R, +_R, \times_R}$ is called the scalar ring of $\struct {S, *_1, *_2, \ldots, *_n, \circ}_R$.
If the scalar ring is understood, then $\struct {S, *_1, *_2, \ldots, *_n, \circ}_R$ can be rendered $\struct {S, *_1, *_2, \ldots, *_n, \circ}$.
Scalar
The elements of the scalar ring $\struct {R, +_R, \times_R}$ are called scalars.
Zero Scalar
The zero of the scalar ring is called the zero scalar and usually denoted $0$, or, if it is necessary to distinguish it from the identity of $\struct {G, +_G}$, by $0_R$.
Definition for Module
Let $\struct {G, +_G, \circ}_R$ be a module, where:
- $\struct {R, +_R, \times_R}$ is a ring
- $\struct {G, +_G}$ is an abelian group
- $\circ: R \times G \to G$ is a binary operation.
Then the ring $\struct {R, +_R, \times_R}$ is called the scalar ring of $\struct {G, +_G, \circ}_R$.
Definition for Unitary Module
Let $\struct {G, +_G, \circ}_R$ be a module, where:
- $\struct {R, +_R, \times_R}$ is a ring with unity
- $\struct {G, +_G}$ is an abelian group
- $\circ: R \times G \to G$ is a binary operation.
Then the ring $\struct {R, +_R, \times_R}$ is called the scalar ring of $\struct {G, +_G, \circ}_R$.
Definition for Vector Space over Division Ring
Let $\struct {G, +_G, \circ}_K$ be a vector space over a division ring, where:
- $\struct {K, +_K, \times_K}$ is a division ring
- $\struct {G, +_G}$ is an abelian group $\struct {G, +_G}$
- $\circ: K \times G \to G$ is a binary operation.
Then the division ring $\struct {K, +_K, \times_K}$ is called the scalar division ring of $\struct {G, +_G, \circ}_K$, or just scalar ring.
Scalar Field
Let $\struct {G, +_G, \circ}_K$ be a vector space, where:
- $\struct {K, +_K, \times_K}$ is a field
- $\struct {G, +_G}$ is an abelian group $\struct {G, +_G}$
- $\circ: K \times G \to G$ is a binary operation.
Then the field $\struct {K, +_K, \times_K}$ is called the scalar field of $\struct {G, +_G, \circ}_K$.