A general method for constructing logarithmic modules in vertex operator
algebra theory is presented. By utilizing this approach, we give explicit
vertex operator construction of certain indecomposable and logarithmic modules
for the triplet vertex algebra W(p) and for other subalgebras of lattice vertex
algebras and their N=1 super extensions.
For every odd p \geq 3, we investigate representation theory of the vertex
algebra WW_{2,p} associated to (2,p) minimal models for the Virasoro algebras.
We demonstrate that vertex algebras WW_{2,p} are C_2-cofinite and irrational.
Complete classification of irreducible representations for WW_{2,3} is
obtained, while the classification for p>3 is subject to certain constant term
identities. These identities can be viewed as "logarithmic deformations" of
Dyson's constant term identities, and are of independent interest.
Generalizing some of our earlier work, we prove natural presentations of the
principal subspaces of the level one standard modules for the untwisted affine
Lie algebras of types A, D and E, and also of certain related spaces. As a
consequence, we obtain a canonical complete set of recursions (q-difference
equations) for the (multi-)graded dimensions of these spaces, and we derive
their graded dimensions. Our methods are based on intertwining operators in
vertex operator algebra theory.