Fundamental legal concepts:a formal and teleological characterisation.

We shall introduce a set of fundamental legal concepts,providing a definition of each of them.This set will include,besides the usual deontic modalities (obligation,prohibition and permission),the following notions:obligative rights (rights related to other's obligations),permissive rights,erga-omnes rights,normative conditionals,liability rights,different kinds of legal powers,potestative rights (rights to produce legal results),result-declarations (acts intended to produce legal determinations),and sources of the law.