Ordering on Positive Integers is Equivalent to Ordering on Natural Numbers

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Theorem

Let $u, v \in \Z_{>0}$ be natural numbers.

Consider the mapping $\phi: \N_{>0} \to \Z_{>0}$ defined as:

$\forall u \in \N_{>0}: \map \phi u = u'$

where $u' \in \Z$ denotes the (strictly) positive integer $\eqclass {b + u, b} {}$.

Let $u', v' \in \Z_{>0}$ be strictly positive integers.

Then:

$u > v \iff u' > v'$


Proof

Let $u' = \eqclass {b + u, b} {}$.

Let $v' = \eqclass {c + v, c} {}$.

Then:

\(\ds u'\) \(>\) \(\ds v'\)
\(\ds \leadstoandfrom \ \ \) \(\ds \eqclass {b + u, b} {}\) \(>\) \(\ds \eqclass {c + v, c} {}\)
\(\ds \leadstoandfrom \ \ \) \(\ds b + u + c\) \(>\) \(\ds c + v + b\)
\(\ds \leadstoandfrom \ \ \) \(\ds u\) \(>\) \(\ds v\)

$\blacksquare$


Sources