English
For any family of lower sets f i, the complement distributes over the infimum: (⨅ i, f i).compl = ⨅ i, (f i).compl.
Русский
Для произвольной семейной функции нижних множеств справедливo: (⨅ i, f i).compl = ⨅ i, (f i).compl.
LaTeX
$$$ (\big \wedge_i f_i).\mathrm{compl} = \big \wedge_i (f_i).\mathrm{compl} $$$
Lean4
protected theorem compl_iInf (f : ι → LowerSet α) : (⨅ i, f i).compl = ⨅ i, (f i).compl :=
UpperSet.ext <| by simp only [coe_compl, coe_iInf, compl_iInter, UpperSet.coe_iInf]