We investigate trace functions of modules for vertex operator algebras satisfying C2-cofiniteness. For the modular invariance property, Zhu assumed two conditions in [Zh]: A(V ) is semisimple and C2-cofiniteness. We show that C2-cofiniteness is enough to prove a modular invariance property. For example, if a VOA V is C2cofinite, then the space spanned by generalized characters (pseudo-trace fun...

We investigate trace functions of modules for vertex operator algebras satisfying C2-cofiniteness. For the modular invariance property, Zhu assumed two conditions in [Zh]: A(V ) is semisimple and C2-cofiniteness. We show that C2cofiniteness is enough to prove a modular invariance property. For example, if a VOA V = ⊕m=0Vm is C2-cofinite, then the space spanned by generalized characters (pseudo-...

To every vertex algebra V we associate a canonical decreasing sequence of subspaces and prove that the associated graded vector space gr(V ) is naturally a vertex Poisson algebra, in particular a commutative vertex algebra. We establish a relation between this decreasing sequence and the sequence Cn introduced by Zhu. By using the (classical) algebra gr(V ), we prove that for any vertex algebra...

We reformed the tensor product theory of vertex operator algebras developed by Huang and Lepowsky so that we could apply it to all vertex operator algebras satisfying C2-cofiniteness. We also showed that the tensor product theory develops naturally if we include not only ordinary modules, but also weak modules with a composition series of finite length (we call it an Artin module). In particula...

The recent researchs show that C2-cofiniteness is a natural conditition to consider a vertex operator algebra with finitely many simple modules. Therefore, we extended the tensor product theory of vertex operator algebras developed by Huang and Lepowsky without assuming the compatibility condition nor the semisimplicity of grading operator so that we could apply it to all vertex operator algebr...

We study the subalgebra of the lattice vertex operator algebra V√ 2A2 consisting of the fixed points of an automorphism which is induced from an order 3 isometry of the root lattice A2. We classify the simple modules for the subalgebra. The rationality and the C2-cofiniteness are also established.

In this paper, some results on vanishing and non-vanishing of generalized local cohomology modules are presented and some relations between those modules and, Ext and ordinary local cohomology modules are studied. Also, several cofiniteness propositions for generalized local cohomology modules are established which, among other things, provide an alternative answer to a question in [Y2].

let $r$ be a commutative noetherian ring with non-zero identity, $fa$ an ideal of $r$, and $x$ an $r$--module. here, for fixed integers $s, t$ and a finite $fa$--torsion $r$--module $n$, we first study the membership of $ext^{s+t}_{r}(n, x)$ and $ext^{s}_{r}(n, h^{t}_{fa}(x))$ in the serre subcategories of the category of $r$--modules. then, we present some conditions which ensure the exi...