Dear categoricians, I'm wondering about the possibility of speaking of trajectories in a category. That is, given a category C, in what sense - if any - can we consider a continuous function R->C (where R are the real numbers). What extra structure is needed on C to consider it as a topological space? what relation with the category structure? I guess there's a link with topos theory, but I can't make it really clear... Subsidiary question: in what case is there a notion of differentiability for the function f? Thank you for direct answers or pointers to (quite easyly understandable) literature. Regards, ---------------------------------- Matthieu Amiguet, doctorant Institut d'Informatique et d'Intelligence Artificielle Université de Neuchatel rue Emile Argand 11 CH - 2000 Neuchatel tel: +41 32 718 27 36 matthieu.amiguet@info.unine.ch ----------------------------------