Bounded lattices
A bounded lattice is a structure L = (L,∨,0,∧,1) such that
(L,∨,∧) is a lattice,
0 is the least element: 0 ≤ x, and
1 is the greatest element: x ≤ 1.
Let L and M be bounded lattices. A morphism from L to M is a function h : L→M that is a homomorphism: h(x∨y) = h(x)∨h(y) and h(x∧y) = h(x)∧h(y) and h(0) = 0 and h(1) = 1.
(P(S),∪,Ø,∩,S), the collection of subsets of a set S, with union, empty set, intersection, and the whole set S.
| Classtype | variety |
| Equational theory | decidable |
| Quasiequational theory | decidable |
| First-order theory | undecidable |
| Congruence distributive | yes |
| Congruence modular | yes |
| Congruence n-permutable | no |
| Congruence regular | no |
| Congruence uniform | no |
| Congruence extension property | no |
| Definable principal congruences | no |
| Equationally definable principal congruences | no |
| Amalgamation property | yes |
| Strong amalgamation property | yes |
| Epimorphisms are surjective | yes |
| Locally finite | no |
| Residual size | unbounded |
[Jobst Heitzig, Jürgen Reinhold, Counting finite lattices, Algebra Universalis 48 (2002) 43--53 MRreview]