Algebra

Named algebraic objects singular enough to have their own page: specific groups, lattices and structures studied as individuals rather than as instances of a general theory. Belongs here: the Monster Group, the largest sporadic simple group; the E8 Lattice and the Leech Lattice, exceptional lattices whose packing density and symmetry group made each famous beyond the algebra that produces it. Does not belong here: the general theory of groups, rings or lattices, which is the branch entity Algebra, not this subcategory, and any object whose defining property is analytic or geometric rather than algebraic even when it happens to carry group structure.