English
A linear WellQuasiOrderedLE is the same as a well-ordered set in the strict sense: WellQuasiOrderedLE α ⇔ WellFoundedLT α.
Русский
Для линейного порядка WQO LE эквивалентно хорошо основанному строгому порядку: WQO LE эквивалентно WellFoundedLT.
LaTeX
$$$\\mathrm{WellQuasiOrderedLE}(\\alpha) \\iff \\mathrm{WellFoundedLT}(\\alpha)$$$
Lean4
/-- A linear WQO is the same thing as a well-order. -/
theorem wellQuasiOrderedLE_iff_wellFoundedLT : WellQuasiOrderedLE α ↔ WellFoundedLT α :=
by
rw [wellQuasiOrderedLE_iff, and_iff_left_iff_imp]
exact fun _ s hs ↦ hs.subsingleton.finite