Approximate fixed-rank closures of covering problems

Consider a 0/1 integer program min{cTx :Ax≥b, x ∈ {0,1}n} where A is nonnegative. We show that if the number of minimal covers of Ax≥b is polynomially bounded, then for any ε>0 and any fixed q, there is a polynomially large lift-and-project relaxation whose value is at least (1−ε) times the value of the rank ≤q relaxation. A special case of this result is that given by set-covering problems, or, generally, problems where the coefficients in A and b are bounded.