English
For f: α → β and s,s' ⊆ β, range f ∩ s ⊂ range f ∩ s' iff f^{-1}(s) ⊂ f^{-1}(s').
Русский
Для отображения f: α → β и подмножеств s, s' ⊆ β: range f ∩ s ⊂ range f ∩ s' эквивалентно f^{-1}(s) ⊂ f^{-1}(s').
LaTeX
$$$ \\text{range } f \\cap s \\;\\subset\\; \\text{range } f \\cap s' \\;\\iff\\; f^{-1}(s) \\;\\subset\\; f^{-1}(s'). $$$
Lean4
theorem range_inter_ssubset_iff_preimage_ssubset {f : α → β} {s s' : Set β} :
range f ∩ s ⊂ range f ∩ s' ↔ f ⁻¹' s ⊂ f ⁻¹' s' :=
by
simp only [Set.ssubset_iff_exists]
apply and_congr ?_ (by aesop)
constructor
all_goals
intro r x hx
simp_all only [subset_inter_iff, inter_subset_left, true_and, mem_preimage, mem_inter_iff, mem_range, true_and]
aesop