congruence lattice
Which lattices occur as intervals in subgroup lattices of finite groups? ★★★★
Author(s):
Conjecture
There exists a finite lattice that is not an interval in the subgroup lattice of a finite group.
Keywords: congruence lattice; finite groups
Finite Lattice Representation Problem ★★★★
Author(s):
Conjecture
There exists a finite lattice which is not the congruence lattice of a finite algebra.
Keywords: congruence lattice; finite algebra