Multipliers, $W$-algebras and the growth of generalized polynomial identities

Abstract: Let $A$ be a $W$-algebra over a field $F$ of characteristic zero, where $W$ is any $F$-algebra. We develop a comprehensive theory of generalized identities independently on the algebraic structure of $W$, using the multiplier algebra of $A.$ We also characterize the generalized varieties of almost polynomial growth generated by finite dimensional $W$-algebras. Finally, we provide a counter-example to the Specht property of generalized $T_W$-ideals in characteristic zero.