Date: Thursday 14th March 2013 br Speaker: Ugo Bruzzo (SISSA) br Title: Noether-Lefschetz theory for hypersurfaces in toric 3-folds br br Abstract: We prove a sufficient criterion for a very general hypersurface in simplicial toric 3-fold to have the same Picard number as the ambient variety. We also give some results about the estimate of the codimension of the locus where the Picard number is bigger.