election_title: "Successive elimination Ex.10 — District I: three voters, the agenda elects C"
scenario_description: |-
  District I of Felsenthal's successive-elimination reinforcement example. Source: Dan S. Felsenthal (2010), Appendix A4, Example 10.
  Three voters, four candidates: A>B>C>D, B>D>C>A, D>C>A>B. Under the agenda B vs D, winner vs A, winner vs C the rounds run B beats D 2:1, A beats B 2:1, C beats A 2:1 — C is elected.
  District II (succ_elim_ex10_district2.yaml) is a single voter who also produces C. Both districts elect C; their union need not, and that is the paradox — see succ_elim_ex10_amalgamated.yaml, where every round ties and the winner becomes an artifact of the tie-break rule.
  Labels are Felsenthal's own, capitalized, so the case can be read beside the paper's table.
  Successive elimination exists in neither the LH engine nor BetterVoting, so this file is tabulated as Ranked Robin, which reads the same pairwise matrix. Ranked Robin elects B here, by a margin tiebreak within a Copeland tie — a different answer from the agenda's C, which is the ordinary state of affairs once the majority preference stops being transitive. Run the procedure with tools_adam/pref_voting_tabulation_engine/successive_elimination_report.py --agenda B,D,A,C.
paradoxes: [multiple-districts]
voting_method: RankedRobin
num_winners: 1
ballots: |-
  1:A>B>C>D
  1:B>D>C>A
  1:D>C>A>B
expected_winners:
  - B

# file: succ_elim_ex10_district1.yaml