1. **Problem Statement:**
Seven committees must elect a chairperson to represent them at the end-of-year board meeting. Some people serve on more than one committee and cannot be elected chairperson for more than one committee. We need to find a system of distinct representatives (SDR) where each committee is assigned a unique chairperson from its members.
2. **Understanding the Problem:**
This is a classic problem of finding a system of distinct representatives, which can be modeled as finding a matching in a bipartite graph. One set of vertices represents the committees, and the other set represents the members. An edge connects a committee to a member if that member belongs to the committee.
3. **Modeling the Problem:**
Committees: Benefits (Bf), Computing (C), Purchasing (P), Recruitment (R), Refreshments (Rf), Social Media (SM), Travel Expenses (TE)
Members: Agatha (A), Dinah (D), Evan (E), Vlad (V), Nancy (N), Leah (L), Omar (O), George (G)
Edges:
- Bf: A, D, E, V
- C: E, N, L, O
- P: G, V, L
- R: D, O, A
- Rf: N, G
- SM: E, L, V, O
- TE: A, V, G
4. **Goal:**
Find a matching where each committee is matched to a unique member who is on that committee, and no member is assigned to more than one committee.
5. **Step-by-step Matching:**
- Assign Refreshments (Rf) to Nancy (N) because N is only in Rf and C (but C has other options).
- Assign Purchasing (P) to George (G) because G is in P, Rf (assigned), and TE.
- Assign Travel Expenses (TE) to Vlad (V) because V is in Bf, P (assigned), SM, TE.
- Assign Benefits (Bf) to Evan (E) because E is in Bf, C, SM.
- Assign Computing (C) to Leah (L) because L is in C, P (assigned), SM.
- Assign Recruitment (R) to Dinah (D) because D is in Bf (assigned), R.
- Assign Social Media (SM) to Omar (O) because O is in C (assigned), R (assigned), SM.
6. **Verification:**
Each committee has a unique member assigned:
- Bf: E
- C: L
- P: G
- R: D
- Rf: N
- SM: O
- TE: V
No member is assigned to more than one committee.
7. **Conclusion:**
A system of distinct representatives exists and is:
Benefits - Evan
Computing - Leah
Purchasing - George
Recruitment - Dinah
Refreshments - Nancy
Social Media - Omar
Travel Expenses - Vlad
This ensures each committee has a unique chairperson who is a member of that committee.
Committee Representatives 83D935
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