====================================================================== SOURCE FILE: cycle_copeland_ties_c4_b21.yaml TABULATED FILE: cycle_copeland_ties_c4_b21_tabulated.txt ====================================================================== election_title: "A cycle Copeland can't break — three trails tie 1-1, and the refined rules all rescue Alder" scenario_description: |- The first worked profile from "Cycle Resolution — why Minimax, Ranked Pairs, and Schulze exist" (05_Ranked_Robin/01_Learn/cycle_resolution.md), now runnable. 21 hikers rank four trails; Dogwood is everyone's last choice, and the other three form a majority CYCLE: Alder beats Birch by 9 · Birch beats Cedar by 11 · Cedar beats Alder by 1 So there is no Condorcet winner, and Ranked Robin's underlying Copeland count (pairwise wins minus losses) ties Alder, Birch and Cedar at +1 each — the simple count cannot pick. That tie-proneness is exactly why the refined cycle-resolution rules exist. Every one of them then agrees on Alder, whose only defeat (to Cedar, by 1) is the mildest loss in the cycle: Minimax picks Alder ("least badly beaten"), Ranked Pairs locks Birch>Cedar and Alder>Birch and skips the cycle-closing Cedar>Alder, Schulze's strongest beat-paths run Alder's way, and Split Cycle discards the weakest defeat in the cycle — Cedar>Alder — leaving Alder undefeated. Four different philosophies, one winner. Verified with pref_voting: uv run STARVote_LH_tabulation_engine/tools_adam/pref_voting_tabulation_engine/cycle_resolution_report.py \ method_comparisons/cycle_resolution/cases/cycle_copeland_ties_c4_b21.yaml LH-only (no BetterVoting election): LH and BV break a Copeland tie differently — LH by margin then lot, BV at random — so a tie-deciding case cannot be frozen on BV. The companion case where the refined rules DISAGREE: cycle_schulze_vs_ranked_pairs_c4_b40.yaml paradoxes: [condorcet-cycle] voting_method: RankedRobin num_winners: 1 lot_numbers: [Alder, Birch, Cedar, Dogwood] ballots: |- 10:Alder>Birch>Cedar>Dogwood 6:Birch>Cedar>Alder>Dogwood 5:Cedar>Alder>Birch>Dogwood expected_winners: - Alder ====================================================================== TABULATION RESULTS ====================================================================== --- Ranked Robin (RCV-RR / Copeland) Method (single winner) --- Tabulating 21 ballots (ranked ballots). Ballots: 10 × Alder > Birch > Cedar > Dogwood 6 × Birch > Cedar > Alder > Dogwood 5 × Cedar > Alder > Birch > Dogwood Round-Robin — every pair, head-to-head (For – Against): Alder beats Birch 15 – 6 Cedar beats Alder 11 – 10 Alder beats Dogwood 21 – 0 Birch beats Cedar 16 – 5 Birch beats Dogwood 21 – 0 Cedar beats Dogwood 21 – 0 --- Pairwise (Round-Robin) Matrix --- Head-to-head / pairwise comparison — the Ranked Robin tally Legend: For - Equal Support - Against (row vs column) | Alder | Birch | Cedar | Dogwood | ---------------------------------------------------------------------- Alder > | --- |15 - 0 - 6 |10 - 0 - 11 |21 - 0 - 0 | Birch > | 6 - 0 - 15 | --- |16 - 0 - 5 |21 - 0 - 0 | Cedar > | 11 - 0 - 10 | 5 - 0 - 16 | --- |21 - 0 - 0 | Dogwood > | 0 - 0 - 21 | 0 - 0 - 21 | 0 - 0 - 21 | --- | 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 Alder 2–1–0 2 +29 Birch, Dogwood 2 Birch 2–1–0 2 +23 Cedar, Dogwood 3 Cedar 2–1–0 2 +11 Alder, Dogwood 4 Dogwood 0–3–0 0 -63 — Winner — Ranked Robin (RCV-RR): Alder *** 3 candidates tie for the most wins (Alder, Birch, Cedar) — a Condorcet cycle (no candidate beats all others). Resolved by total margin, then lot order. (This is where Minimax / Ranked Pairs / Schulze differ — see 05_Ranked_Robin/01_Learn/cycle_resolution.md.) --- 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 (3 of 4): Alder, Birch, Cedar Outside (1): Dogwood More than one member ⇒ NO Condorcet winner: the top of the tournament is a cycle, so the strongest "candidate" is a set, not a person. Which member of the set should win is exactly what Minimax / Ranked Pairs / Schulze disagree about — see 05_Ranked_Robin/01_Learn/cycle_resolution.md. Ranked Robin (RCV-RR) winner Alder 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