A <preorder> is \b[reflexive and transitive]: $xRx$ for every element, and $xRy,yRz$ imply $xRz$. A <partial order> additionally requires \b[<antisymmetry>]: $xRy$ and $yRx$ imply $x=y$. It need not compare every pair of distinct elements.

Solution

Past exam of the year 1 of the computer science course of the University of Oxford / 2017 / Discrete mathematics, continuous mathematics and probability / 3 / e / i / Solution

 Solution (source code)