2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/1144A deep blind HI survey of the nearby spiral rich Ursa Major cluster has been performed with the VLA in parallel with a wide-field R-band imaging campaign of most VLA fields with the CFHT. The goal is to measure the slope of the HI mass function down to HI masses of 10^7 Msun as well as the slope of the faint-end of the luminosity function down to M(R)=-10. The VLA survey sampled 16% of the Ursa Major cluster volume. Both the HIMF and the LF in Ursa Major are nearly flat at their faint-ends. No free- floating HI clouds were detected.7 pages, 3 figures. Contribution to the Guanajuato meeting "Mapping the Hidden Universe". To appear in PASP, 2000Astrophysicstext