Title: Four-dimensional Lens Space Index from Two-dimensional Chiral Algebra,
Abstract: We study the supersymmetric partition function on $S^1 \times L(r, 1)$, or
the lens space index of four-dimensional $\mathcal{N}=2$ superconformal field
theories and their connection to two-dimensional chiral algebras. We primarily
focus on free theories as well as Argyres-Douglas theories of type $(A_1, A_k)$
and $(A_1, D_k)$. We observe that in specific limits, the lens space index is
reproduced in terms of the (refined) character of an appropriately twisted
module of the associated two-dimensional chiral algebra or a generalized vertex
operator algebra. The particular twisted module is determined by the choice of
discrete holonomies for the flavor symmetry in four-dimensions.