• Fill up the diagram of separation axioms, using, for instance,  the examples we saw in class.
• Recall the picture of the space of "orbits" of the vector field on the plane defined by X(x,y)=(x,-y). What is the topology on the set of orbits? (Recall that a subset S of orbits is open in the space of orbits, if and only if the union of the elements of S is an open subset of the plane with the standard topology).