English
A model satisfies noTopOrderSentence iff NoTopOrder holds in the domain.
Русский
Модель удовлетворяет noTopOrderSentence тогда и только тогда, когда в множестве нет верхнего элемента.
LaTeX
$$$ M \\models L.noTopOrderSentence \\iff NoTopOrder M $$$
Lean4
theorem realize_noTopOrder_iff : M ⊨ L.noTopOrderSentence ↔ NoTopOrder M :=
by
simp only [noTopOrderSentence, Sentence.Realize, Formula.Realize, BoundedFormula.realize_all,
BoundedFormula.realize_ex, BoundedFormula.realize_not, Term.realize_le]
refine ⟨fun h => ⟨fun a => h a⟩, ?_⟩
intro h a
exact exists_not_le a