 This theory has the global symmetry formula_4, which is often called the flavor symmetry, and this has a 't Hooft anomaly.The anomaly matching condition by G. 't Hooft proposes that a 't Hooft anomaly of continuous symmetry can be computed both in the high-energy and low-energy degrees of freedom (“UV” and “IR”) and give the same answer.For example, consider the quantum chromodynamics with "N"f massless quarks.