  We propose quantum states for Little String Theories (LSTs) arising from M5
branes probing A- and D-type singularities. This extends Witten's picture of M5
brane partition functions as theta functions to this more general setup.
Compactifying the world-volume of the five-branes on a two-torus, we find that
the corresponding theta functions are sections of line bundles over complex
4-tori. This formalism allows us to derive Seiberg-Witten curves for the
resulting four-dimensional theories. Along the way, we prove a duality for LSTs
observed by Iqbal, Hohenegger and Rey.
