  Ballistic deposition (BD) is considered to be a paradigmatic discrete growth
model that represents the Kardar-Parisi-Zhang (KPZ) universality class. In this
paper we question this connection by rigorously deriving a formal continuum
equation from the BD microscopic rules, which deviates from the KPZ equation.
In one dimension these deviations are not important in the presence of noise,
but for higher dimensions or when considering deterministic evolution they are
very relevant.
