Web Science/Part2: Emerging Web Properties/Modeling the Web as a graph/Reviewing terms from graph theory/quiz

{Which of these terms describe the axioms for a bipartite graph $$G(V,E)$$ with $$U_1,U_2$$ being the disjoint split of the vertices?} - $$\forall e = (u,v) \in E : \exists w \in V : (u,w), (w,u) \in E$$ - $$\forall e = (u,v) \in E : (v,u) \in E$$ + $$\forall e = (u,v) \in E : u\in U_1 \land v\in U_2 \lor v \in U_1 \land u \in U_2$$ - $$\forall e = (u,v) \in E : u\in U_1 \lor v\in U_2 \land v \in U_1 \lor u \in U_2$$ - $$\forall e = (u,v) \in E : u\in U_1 \lor v\in U_2 \lor v \in U_1 \lor u \in U_2$$

{What kind of mathematical object is used to describe a graph labeling?} - set - element + function - matrix - vector - String

{which of the following are types of graphs that you know?} - heavy graphs - complex graphs + directed graphs - difficult graphs + bipartite graphs + robust graphs - web graphs + weighted graphs
 * as a mathematical object web graphs do not exist. we use graphs to model the web graph