A large class of N = 2 quantum field theories admits a BPS quiver description and the study of their BPS spectra is then reduced to a representation theory problem. In such theories the coupling to a line defect can be modelled by framed quivers. The associated spectral problem characterises the line defect completely. Framed BPS states can be thought of as BPS particles bound to the defect. We identify the framed BPS degeneracies with certain enumerative invariants associated with the moduli spaces of stable quiver representations. We develop a formalism based on equivariant localization to compute explicitly such BPS invariants, for a particular choice of stability condition. Our framework gives a purely combinatorial solution of this problem. We detail our formalism with several explicit examples.Once again to construct the pyramid arrangement we have to look at the relevant terms in the Jacobian algebra J W = ⊕ n≥0 J W,n :Now we write down the Jacobian algebra elements corresponding to cyclic modules (6.32) and summands with higher grading do not contribute to the classification of the fixed points due to the condition dim V f = 1 and equations (6.15) and (6.18) evaluated at B =B = 0. To write down J W,4 we have usedthanks to (6.16) and (6.24) respectively, andWe can write the cyclic elements of the Jacobian algebra as A 2ψ A 1 C 3 v} . (6.44) the cyclic vector v. As usual this is graded J W = n≥0 J W,n and the first few terms are is obtained from the analog situation for SU (3), equation (6.14). To build the pyramid arrangement we have to study modules generated by the action of the Jacobian algebra on a single vector v ∈ V f , with V f one dimensional. The Jacobian algebra thus generated is naturally graded J W = n≥0 J W,n , and the first few terms are easy to work outAt the next levels we have four independent vectorswhere we have used the F-term relations obtained from (7.16) to show7.19) 56 Similar arguments give J W,7 = {ψà 2 ψ A 3 φà 1C v ,ψ A 2 ψ A 3 φà 1C v} , J W,8 = {A 3ψÃ2 ψ A 3 φà 1C v ,à 3ψÃ2 ψ A 3 φà 1C v} , J W,9 = {φ A 3ψÃ2 ψ A 3 φà 1C v ,φà 3ψÃ2 ψ A 3 φà 1C v} , J W,10 = {à 1φ A 3ψÃ2 ψ A 3 φà 1C v , A 1φ A 3ψÃ2 ψ A 3 φà 1C v} . (7.20)