  Recent experiments at RHIC and theoretical considerations indicate that the
quark-gluon plasma, present in the fireball of relativistic heavy-ion
collisions, might be in a liquid phase. The liquid state can be identified by
characteristic correlation and structure functions. Here definitions of the
structure functions and pair correlations of the quark-gluon plasma are
presented as well as perturbative results. These definitions might be useful
for verifying the quark-gluon-plasma liquid in QCD lattice calculations.
