Definition:Total Ordering Induced by Strict Positivity Property
Contents
Definition
Let $\struct {D, +, \times, \le}$ be an ordered integral whose zero is $0_D$ and whose unity is $1_D$.
Let $P: D \to \set {\mathrm T, \mathrm F}$ denote the strict positivity property:
\((P \, 1)\) | $:$ | Closure under Ring Addition: | \(\displaystyle \forall a, b \in D:\) | \(\displaystyle \map P a \land \map P b \implies \map P {a + b} \) | ||||
\((P \, 2)\) | $:$ | Closure under Ring Product: | \(\displaystyle \forall a, b \in D:\) | \(\displaystyle \map P a \land \map P b \implies \map P {a \times b} \) | ||||
\((P \, 3)\) | $:$ | Trichotomy Law: | \(\displaystyle \forall a \in D:\) | \(\displaystyle \map P a \lor \map P {-a} \lor a = 0_D \) | ||||
For $P \, 3$, exactly one condition applies for all $a \in D$. |
Then the total ordering $\le$ compatible with the ring structure of $D$ is called the (total) ordering induced by (the strict positivity property) $P$.
Also known as
The (total) ordering induced by (the strict positivity property) $P$ is also seen as (total) ordering defined by (the strict positivity property) $P$.
The strict positivity property is generally known as the positivity property, but on $\mathsf{Pr} \infty \mathsf{fWiki}$ we place emphasis on the strictness.
Also see
This ordering is shown to exist by Strict Positivity Property induces Total Ordering.
Sources
- 1969: C.R.J. Clapham: Introduction to Abstract Algebra ... (previous) ... (next): Chapter $2$: Ordered and Well-Ordered Integral Domains: $\S 7$. Order