Corrections to finite-size scaling in the lattice N-vector model for N=infinity

We compute the corrections to finite-size scaling for the N-vector model on the square lattice in the large-N limit. We find that corrections behave as log L/L(2). For tree-level improved Hamiltonians corrections behave as 1/L(2). In general l-loop improvement is expected to reduce this behavior to 1/(L(2)log(l)L). We show that the finite-size scaling limit and the perturbative limit do not commute in the calculation of the corrections to finite-size scaling. We present a detailed study of the corrections for the RP(infinity) model. [S0556-2821(98)03520-6].