We study (analytic) finite-size corrections in the dense polymer model on the
strip by perturbing the critical Hamiltonian with irrelevant operators
belonging to the tower of the identity. We generalize the perturbation
expansion to include Jordan cells, and examine whether the finite-size
corrections are sensitive to the properties of indecomposable representations
appearing in the conformal spectrum, in particular their indecomposability
parameters. We find, at first order, that the corrections do not depend on
these parameters nor even on the presence of Jordan cells. Though the
corrections themselves are not universal, the ratios are universal and
correctly reproduced by the conformal perturbative approach, to first order.Comment: 5 pages, published versio