... particular elements. (A careful study of ≈ is given in Chapter II.) A Course in Universal Algebra H. P. Sankappanavar Stanley Burris With 36 Illustrationsc S. Burris and H. P. Sankappanavar All ... classical algebra; for example heshould know what groups and rings are.We will assume a familiarity with the most basic notions of set theory. Actually, we useclasses as well as sets. A class of sets ... L1;inthiscasewealsosayL2contains a copy of L1as a sublattice.Exercises §21. If (X, T ) is a topological space, show that the closed subsets, as well as the opensubsets, form a lattice using...