English
Under suitable distributive lattice structure, the truncatedInf of s ⊼ t at a equals the infimum of truncatedInf s a and truncatedInf t a.
Русский
В распределимой решётке для s ⊼ t выполняется truncatedInf(s ⊼ t) a = truncatedInf s a ⊓ truncatedInf t a.
LaTeX
$$$\operatorname{truncatedInf}(s \; \sqcap \; t) \, a = \operatorname{truncatedInf} s \, a \sqcap \operatorname{truncatedInf} t \, a$$$
Lean4
theorem truncatedInf_le : truncatedInf s a ≤ a := by
unfold truncatedInf
split_ifs with h
· obtain ⟨b, hb, hba⟩ := h
exact hba.trans' <| inf'_le id <| mem_filter.2 ⟨hb, ‹_›⟩
· exact bot_le