Condorcet cycle
Named by 4 essays across one field — each of them below, with the objects they name alongside it.
Also named here as pairwise majority, voting rule — the same set of essays touches all of them, so they are one junction rather than several.
The majority that goes in a circle
Every voter hands in a ranking, and a ranking is transitive by construction. Compare the candidates two at a time and let the majority decide each pair, and the verdicts need not fit together into a ranking at all.
Five rules and five winners
Twenty-seven ranked ballots, five entirely reasonable ways of counting them, and five different candidates declared the winner. Every count is correct, every rule is defensible, and the answer turns out to be a property of the rule rather than of the ballots.
Four conditions, and no rule that has all of them
The rung below shows five reasonable rules returning five different winners, which invites the obvious question of which one is right. The answer is that the conditions anybody would write down cannot all hold at once — and here each named rule's own violation is found by search rather than quoted.
A lie that pays
Three rungs of this ladder have read a ballot as a report of a preference. This one reads it as a move, and walks every move one voter has — all six rankings, the winner each produces, and the ones that beat honesty.
Named alongside it
The objects these essays reach for when they reach for this one.
Pairwise majorityPreference profileVoting ruleCounterexampleIndependence of irrelevant alternativesArrows theoremBorda countCounting argumentDecisive setGraphInstant runoffProof by contradiction