A proof on interval order
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Let $X$ be a nonempty finite set and $≻$ a binary relation on X. We say that $≻$ is an interval order if $x≻y$ and $x'≻y'$ imply either $x≻y'$ or $x'≻y$, for every $x$,$y$,$x'$ and $y'$ in $X$.
Prove that $≻$ is an interval order iff there exist two real functions $f$ and $g$ on $X$ such that $x≻y$ iff $f(x)>g(y)$ for every $x$ and $y$ in $X$.
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Let $X$ be a nonempty finite set and $≻$ a binary relation on X. We say that $≻$ is an interval order if $x≻y$ and $x'≻y'$ imply either $x≻y'$ or $x'≻y$, for every $x$,$y$,$x'$ and $y'$ in $X$.
Prove that $≻$ is an interval order iff there exist two real functions $f$ and $g$ on $X$ such that $x≻y$ iff $f(x)>g(y)$ for every $x$ and $y$ in $X$.
set-theory
New contributor
add a comment |
up vote
-1
down vote
favorite
up vote
-1
down vote
favorite
Let $X$ be a nonempty finite set and $≻$ a binary relation on X. We say that $≻$ is an interval order if $x≻y$ and $x'≻y'$ imply either $x≻y'$ or $x'≻y$, for every $x$,$y$,$x'$ and $y'$ in $X$.
Prove that $≻$ is an interval order iff there exist two real functions $f$ and $g$ on $X$ such that $x≻y$ iff $f(x)>g(y)$ for every $x$ and $y$ in $X$.
set-theory
New contributor
Let $X$ be a nonempty finite set and $≻$ a binary relation on X. We say that $≻$ is an interval order if $x≻y$ and $x'≻y'$ imply either $x≻y'$ or $x'≻y$, for every $x$,$y$,$x'$ and $y'$ in $X$.
Prove that $≻$ is an interval order iff there exist two real functions $f$ and $g$ on $X$ such that $x≻y$ iff $f(x)>g(y)$ for every $x$ and $y$ in $X$.
set-theory
set-theory
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qwert3
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