Question: 1. Find a spanning tree of the graph at left in Figure.
2. Find a spanning tree of the graph at right in Figure.
3. Let A = {(2,5),(-3,1),(4,2),(1,1),(0,1)}. List the elements in each of the following sets (or write /0 if appropriate).
(a) {(a1, a2) ∈ A | a1 2}.
(b) {a1 | (a1, a2) ∈ A and a1 > a2}.
(c) {a2 | (a1, a2) ∈ A and a2 = 0}.