“…These theories admit supersymmetric line defects which are associated to the spectral problem of computing framed BPS states [26]. In many cases such a problem can be approached by localization on quiver moduli spaces [9,12,13,14,16], or on the moduli spaces of semiclassical configurations [5,33], by using cluster algebras [3,10,11,41], or via BPS graphs or spectral networks [22,23,28,35].…”