The paper extends the notion of braided set and its close relative -the Yang-Baxter set -to the category of vector spaces and explore structure aspects of such a notion as morphisms and extensions. In this way we describe a family of solutions for the Yang-Baxter equation on B ⊗ C (on B × C, respectively) if given (B, R B ) and (C, R C ) are two linear (set-theoretic) solutions of the Yang-Baxter equation. One of the key observation is the relation of this question with the virtual pure braid group.