Students' mathematical c-knowledge usually has a local nature, thus, it seems relevant to question the characteristics to which an education system should aspire to favour the decontextualization of c-knowledge. This question was studied in the light of the Theory of Didactical Situations (Brousseau, 1998). Thus, the didactic conditions aiming at facilitating the relationship between the adidactical situations and the institutionalization were identified in the analysis of scientific writings and tested on students with learning difficulties. The results would lead us, on the one hand, to determine the interest and the limits of the different underlying conditions and, on the other hand, to make a few didactical statements that would favour the transition from a local c-knowledge to a decontextualized s-knowledge.