Total Order

🅟 Feb 22, 2026

  🅤 Jul 09, 2026

Definition 1.

A total order is a strongly connected partial order, i.e. a binary relation $\leq$ on $X$ such that:

  1. (Reflexivity) For all $x \in X$,

    \[x \leq x.\]
  2. (Transitivity) For all $x$, $y$, $z\in X$,

    \[x \leq y \,\land\, y\leq z \enspace\rimp\enspace x \leq z.\]
  3. (Antisymmetry) For all $x$, $y \in X$,

    \[x \leq y \,\land\, y\leq x \enspace\rimp\enspace x = y.\]
  4. (Strong connection) For all $x$, $y \in X$,

    \[x \leq y \enspace\lor\enspace y \leq x.\]

Definition 2.

A strict total order is a connected strict partial order, i.e. a binary relation $<$ on $X$ such that:

  1. (Irreflexivity) For all $x \in X$,

    \[x \nless x.\]
  2. (Transitivity) For all $x$, $y$, $z \in X$,

    \[x < y \,\land\, y < z \enspace\rimp\enspace x < z.\]
  3. (Asymmetry) For all $x$, $y \in X$,

    \[x < y \enspace\rimp\enspace y \nless x.\]
  4. (Connection) For all $x$, $y \in X$,

    \[x < y \enspace\lor\enspace y < x \enspace\lor\enspace x = y.\]

Proposition 1.

$\leq$ is a total order if and only if $<$ is a strict total order.