AQA D1 2007 June — Question 1

Exam BoardAQA
ModuleD1 (Decision Mathematics 1)
Year2007
SessionJune
TopicMatchings and Allocation

1 Six people, \(A , B , C , D , E\) and \(F\), are to be matched to six tasks, \(1,2,3,4,5\) and 6 . The following adjacency matrix shows the possible matching of people to tasks.
Task 1Task 2Task 3Task 4Task 5Task 6
A010100
B101010
\(\boldsymbol { C }\)001011
D000100
E010001
\(\boldsymbol { F }\)000110
  1. Show this information on a bipartite graph.
  2. At first \(F\) insists on being matched to task 4. Explain why, in this case, a complete matching is impossible.
  3. To find a complete matching \(F\) agrees to be assigned to either task 4 or task 5. Initially \(B\) is matched to task 3, \(C\) to task 6, \(E\) to task 2 and \(F\) to task 4.
    From this initial matching, use the maximum matching algorithm to obtain a complete matching. List your complete matching.