[...] a property called "factivity" [Kiparsky, P. and Kiparsky, C., Fact, in Bierwisch, M. And Heidolph, K., eds., “Progress in Linguistics”, Mouton, The Hague, pp. 143-173], where the object proposition is assumed to be a fact regardless of what modality the whole sentence carries. - Pustejovsky & Boguraev (2004), a pag.339