English
For the cofinite filter, bliminf s cofinite p equals the set of x such that {n | p n ∧ x ∉ s n} is Finite.
Русский
Для cofinite bliminf s cofinite p множество x : {n | p n ∧ x ∉ s n} конечно.
LaTeX
$$bliminf s cofinite p = {x | {n | p n ∧ x ∉ s n}.Finite}$$
Lean4
theorem bliminf_set_eq : bliminf s cofinite p = {x | {n | p n ∧ x ∉ s n}.Finite} :=
by
rw [← compl_inj_iff]
simp only [bliminf_eq_iSup_biInf, compl_iInf, compl_iSup, ← blimsup_eq_iInf_biSup, cofinite.blimsup_set_eq]
rfl