  We summarize recent work on the characterization of anomaly poles in
connection with the field-theory interpretation of the Green-Schwarz mechanism
of anomaly cancellation and on their effective field theories, stressing on the
properties of the anomaly vertex in two representations, the Rosenberg and the
Longitudinal/Transverse. The presence of polar amplitudes in these theories
causes a violation of unitarity at high energy which is cured by the exchange
of the axion. We comment on the possible physical implications of this
mechanism.
