Axiomatic characterization of physical geometry

"Maurice Duverger is arguably the most distinguished French political scientist of the last century, but his major impact has been largely in the English-speaking world. His book, Political Parties, first translated into English in 1954, has influenced both the party politics literature (which continues to make use of his typology of party organization) and the electoral systems literature. His chief contributions there deal with what have come to be called in his honor Duverger's Law and Duverger's Hypothesis. The first argues that countries with the plurality rule will tend to become two-party systems; the second argues that countries using proportional representation (PR) will tend to become multi-party systems. Duverger also identifies specific mechanisms that will produce these effects, conventionally referred to as "mechanical effects" and "psychological effects." However, while Duverger's Hypothesis concerning the link between PR and multipartism is now widely accepted, the empirical evidence that plurality voting results in two-party systems is remarkably weak--with the U.S. the most notable exception. The chapters in this volume consider national-level evidence about Duver