Exploring the lower mass function in the young open cluster IC 4665 W. J. de Wit, J. Bouvier, F. Palla, J.-C. Cuillandre, D. J. James, T. R. Kendall, N. Lodieu, M. J. McCaughrean, E. Moraux, S. Randich and L. Testi A&A, 448 1 (2006) 189-202 Published online: 17 February 2006 DOI: 10.1051/0004-6361:20054102