The electric quarks give copies of the fundamental, so
In the magnetic theory the color components of transform as flavor antifundamentals and contribute . The singlet is the two-index antisymmetric representation of , whose cubic anomaly coefficient is . Hence
This is a direct anomaly check of Seiberg duality.
Two theories are Seiberg duals when they are distinct ultraviolet gauge theories that flow to the same infrared quantum field theory. Their gauge-invariant operator spectra, global symmetries, 't Hooft anomalies and responses to deformations agree, even though one description may be strongly coupled where the other is weakly coupled.
Choose the flavor orientation in which each electric is a fundamental of . Its color components then give
In the magnetic theory, the eight Spin(8) components of transform in the antifundamental and contribute . The singlet transforms in the symmetric representation of , whose cubic anomaly coefficient is , while and are flavor singlets. Therefore
where was used. The two 't Hooft anomalies match, as required by Seiberg duality.
Only the Spin(8) vectors and the one spinor contribute to the magnetic gauge beta function. The supplied indices give
The magnetic theory is infrared free when , namely
At the one-loop coefficient vanishes and higher-order dynamics decides the flow. For , Seiberg duality says that the strongly coupled low-energy limit of the asymptotically free electric theory is described by the weakly coupled Spin(8) fields and the superpotential from part v.