A module M is called distributive if the lattice Lat(M) of all its
submodules is distributive, i.e., Fn(G ] H) = FnG + FnH for all
submodules F, G, and H of the module M. A module M is called uniserial
if all its submodules are comparable with respect to inclusion, i.e.,
the lattice Lat(M) is a chain. Any direct sum of distributive (resp.
uniserial) modules is called a semidistributive (resp. serial) module.
The class of distributive (resp. semidistributive) modules properly
cont.ains the class ofall uniserial (resp. serial) modules. In
particular, all simple (resp. semisimple) modules are distributive
(resp. semidistributive). All strongly regular rings (for example, all
factor rings of direct products of division rings and all commutative
regular rings) are distributive; all valuation rings in division rings
and all commutative Dedekind rings (e.g., rings of integral algebraic
numbers or commutative principal ideal rings) are distributive. A module
is called a Bezout module or a locally cyclic module ifevery finitely
generated submodule is cyclic. If all maximal right ideals of a ring A
are ideals (e.g., if A is commutative), then all Bezout A-modules are
distributive