  A proposal to link the equation of state of a monocomponent hard-disk fluid
to the equation of state of a polydisperse hard-disk mixture is presented.
Event-driven molecular dynamics simulations are performed to obtain data for
the compressibility factor of the monocomponent fluid and of 26 polydisperse
mixtures with different size distributions. Those data are used to assess the
proposal and to infer the values of the compressibility factor of the
monocomponent hard-disk fluid in the metastable region from those of mixtures
in the high-density region. The collapse of the curves for the different
mixtures is excellent in the stable region. In the metastable regime, except
for two mixtures in which crystallization is present, the outcome of the
approach exhibits a rather good performance. The simulation results indicate
that a (reduced) variance of the size distribution larger than about $0.01$ is
sufficient to avoid crystallization and explore the metastable fluid branch.
