We study a W -algebra of central charge 2(k − 1)/(k + 2), k = 2, 3, . . . contained in the commutant of a Heisenberg algebra in a simple affine vertex operator algebra L(k, 0) of type A (1) 1 with level k. We calculate the operator product expansions of the W -algebra. We also calculate some singular vectors in the case k ≤ 6 and determine the irreducible modules and Zhu’s algebra. Furthermore,...

The semijoin algebra is the variant of the relational algebra obtained by replacing the join operator by the semijoin operator. We discuss some interesting connections between the semijoin algebra and the guarded fragment of first-order logic. We also provide an Ehrenfeucht-Fräıssé game, characterizing the discerning power of the semijoin algebra. This game gives a method for showing that certa...

the aim of this paper is to introduce the notions of ($epsilon, epsilon vee q$)-fuzzy p-ideals, ($epsilon, epsilon vee q$)-fuzzy q-ideals and ($epsilon, epsilon vee q$)-fuzzy a-ideals in bcialgebras and to investigate some of their properties. several characterizationtheorems for these generalized fuzzy ideals are proved and the relationshipamong these generalized fuzzy ideals of bci-algebras i...

This paper seeks to construct a representation of the algebra of angular momentum (SU(2) algebra) in terms of the operator relations corresponding to Gentile statistics in which one quantum state can be occupied by n particles. First, we present an operator realization of Gentile statistics. Then, we propose a representation of angular momenta. The result shows that there exist certain underlyi...

Let V be a simple unitary vertex operator algebra and U (polynomially) energy-bounded subalgebra containing the conformal vector of V. We give two sufficient conditions implying that is energy-bounded. The first condition compact orbifold for some group G automorphisms second exponentially it finite direct sum U-modules. As consequence condition, we prove if regular V, then $V$ In particular, e...