Locally cyclic group

Symbol-free definition
A group is termed locally cyclic if it satisfies the following equivalent conditions:


 * 1) Every finitely generated subgroup of the group is cyclic.
 * 2) The subgroup generated by any two elements of the group is cyclic.
 * 3) It is isomorphic to a subquotient (i.e., a quotient group of a subgroup) of the group of rational numbers.
 * 4) Its lattice of subgroups is a distributive lattice. In other words, the operations of join of subgroups and intersection of subgroups distribute over each other.

Equivalence of definitions
(1) and (2) are clearly equivalent. For the equivalence of (1) and (2) with (3), refer locally cyclic iff subquotient of rationals. For the equivalence with (4), refer locally cyclic iff distributive lattice of subgroups.