  A gauge theory of pions interacting with rho-mesons at elevated temperatures
is used to calculate the pressure in a hot pion gas. No reference is made to
the pion's status as a QCD Goldstone boson. The role of the pion is merely that
of a carrier of an SU(2) symmetry, gauged to create a vector-meson interaction,
the rho playing the role of the interacting vector particle. The results are in
rough agreement with much more elaborate calculations, both of the purely
hadronic variety, and those that invoke quark-gluon degrees of freedom. The
quark-gluon and purely hadronic calculations seemingly lead to very similar
predictions which are in accord with receent data from RHIC. The results
motivate the question as to whether the two descriptions are dual to each other
in the sense of being alternate models, each sufficient to explain the observed
data.
