Tag
filter
2 resources tagged “filter” across the knowledge library.
2 items
Guide6 Aug 2026Filters, Ideals and UltrafiltersFilters and ideals on a Boolean algebra, principal and free filters, ultrafilters and their three equivalent characterisations, and the role of ultrafilters throughout the rest of the subject.6 min readRead MoreGuide6 Aug 2026Reduced Products and Filtered ProductsReduced products over a filter, the congruence they induce, the direct product and ultraproduct as extreme cases, and the Horn sentence preservation theorem.5 min readRead More