====================================================================== SOURCE FILE: bv2153_pcttmr_ranked_robin.yaml TABULATED FILE: bv2153_pcttmr_ranked_robin_tabulated.txt ====================================================================== election_title: "Felsenthal Ex.7 — Ranked Robin: the Condorcet winner Amos" scenario_description: |- Race 3 of 3 in the Absolute-Majority-paradox election (BV2153, bvid pcttmr; BV-confirmed). Source: Dan S. Felsenthal (2010), Appendix A3, Example 7 — see bv2153_pcttmr_approval.yaml for the setup. The same 100 voters' full rankings counted by Ranked Robin (Copeland): Amos wins both head-to-heads (Bella 51–49, Chad 51–49) — the Condorcet winner, elected. A majority's first choice survives any pairwise count; it is the approval cutoff, not the ballots, that loses him. Live results: https://bettervoting.com/pcttmr/results bv_test_id: BV2153 bv_election_id: pcttmr bv_results_url: https://bettervoting.com/pcttmr/results paradoxes: [majority-failure] voting_method: RankedRobin num_winners: 1 ballots: |- 51:Amos>Bella>Chad 48:Bella>Chad>Amos 1:Chad>Bella>Amos expected_winners: - Amos # file: bv2153_pcttmr_ranked_robin.yaml ====================================================================== TABULATION RESULTS ====================================================================== --- Ranked Robin (RCV-RR / Copeland) Method (single winner) --- Tabulating 100 ballots (ranked ballots). Ballots: 51 × Amos > Bella > Chad 48 × Bella > Chad > Amos 1 × Chad > Bella > Amos Round-Robin — every pair, head-to-head (For – Against): Amos beats Bella 51 – 49 Amos beats Chad 51 – 49 Bella beats Chad 99 – 1 --- Pairwise (Round-Robin) Matrix --- Head-to-head / pairwise comparison — the Ranked Robin tally Legend: For - Equal Support - Against (row vs column) | Amos | Bella | Chad | ------------------------------------------------------ Amos > | --- |51 - 0 - 49 |51 - 0 - 49 | Bella > | 49 - 0 - 51 | --- |99 - 0 - 1 | Chad > | 49 - 0 - 51 | 1 - 0 - 99 | --- | Win–loss record — Copeland score = wins + ½·ties (highest score wins; ties broken by total margin, then lot order): # Candidate W–L–T Copeland Margin Beats 1 Amos 2–0–0 2 +4 Bella, Chad 2 Bella 1–1–0 1 +96 Chad 3 Chad 0–2–0 0 -100 — Winner — Ranked Robin (RCV-RR): Amos beats every opponent head-to-head — the Condorcet winner. --- Smith Set (the generalized Condorcet winner) --- The smallest group whose every member beats every candidate outside it — the honest answer to "who is even in contention?". Smith set (1 of 3): Amos Outside (2): Bella, Chad One member ⇒ Amos is the Condorcet winner, beating every rival head-to-head. Ranked Robin (RCV-RR) winner Amos is INSIDE the Smith set. ✓ Guaranteed: Ranked Robin (Copeland) is Smith-efficient — every member of the set outscores every outsider, so the top of the win–loss table is always inside the set, however the tie among them is then broken. More: 07_Concepts/topics/smith_set.md