English
ordSeparatingSet (ofDual^{-1} s) (ofDual^{-1} t) = ofDual^{-1} (ordSeparatingSet s t).
Русский
ordSeparatingSet в двойственной перестановке равен образу ordSeparatingSet s t под двойственным отображением.
LaTeX
$$ordSeparatingSet (ofDual^{-1} \,' s) (ofDual^{-1} t) = ofDual^{-1} (ordSeparatingSet s t)$$
Lean4
theorem dual_ordSeparatingSet : ordSeparatingSet (ofDual ⁻¹' s) (ofDual ⁻¹' t) = ofDual ⁻¹' ordSeparatingSet s t := by
simp only [ordSeparatingSet, mem_preimage, ← toDual.surjective.iUnion_comp, ofDual_toDual, dual_ordConnectedComponent,
← preimage_compl, preimage_inter, preimage_iUnion]