English
If a relation R on a set A is trichotomous, then the swapped relation on A is trichotomous.
Русский
Если отношение R на множестве A тричотомично, то переставленное отношение тричотомично.
LaTeX
$$$\\forall a,b:\\alpha,\\; \\text{Trichotomous}(r)(a,b) \\Rightarrow \\text{Trichotomous}(swap\\,r)(a,b)$$$
Lean4
theorem swap (r) [IsTrichotomous α r] : IsTrichotomous α (swap r) :=
⟨fun a b => by simpa [Function.swap, or_comm, or_left_comm] using trichotomous_of r a b⟩