On the Sums of Functions Satisfying the Condition (s1)

A function f:{\mathR} \to {\mathR} satisfies the condition (s_1) if for each real r > 0, for each x, and for each set U \ni x belonging to the density topology there is an open interval I such that C(f) \supset I \cap U \neq \emptyset and f(U\cap I) \subset (f(x)-r,f(x)+r). (C(f) denotes the set of all continuity points of f). In this article we investigate the sums of two Darboux functions satisfying the condition (s_1).