Complex sentence: For simplicity, we will assume that the underlying background geometry is Galilean, and that this Galilean spacetime is filled with an isotropic inviscid fluid at zero temperature (e.g. a superfluid).
Split into simpler sentences: For simplicity, we will assume that the underlying background geometry is Galilean. We will also assume that this Galilean spacetime is filled with an isotropic inviscid fluid at zero temperature (e.g. a superfluid).