  Adopting a single-zone framework, with accretion of primordial gas on a
free-fall timescale, the chemical evolution of the Galactic bulge is
calculated, assuming (i) a corresponding rapid timescale for star formation,
and (ii) an initial mass function biased towards massive stars. We emphasise
here the uncertainties associated with the underlying physics (specifically,
stellar nucleosynthesis) and how those uncertainties are manifest in the
predicted abundance ratio patterns in the resulting present-day Galactic bulge
stellar populations.
