  Polyhedral projection is a main operation of the polyhedron abstract
domain.It can be computed via parametric linear programming (PLP), which is
more efficient than the classic Fourier-Motzkin elimination method.In prior
work, PLP was done in arbitrary precision rational arithmetic.In this paper, we
present an approach where most of the computation is performed in
floating-point arithmetic, then exact rational results are reconstructed.We
also propose a workaround for a difficulty that plagued previous attempts at
using PLP for computations on polyhedra: in general the linear programming
problems are degenerate, resulting in redundant computations and geometric
descriptions.
