TWO‐DIMENSIONAL BERTRAND COMPETITION: BLOCK METRIC, EUCLIDEAN METRIC, AND WAVES OF ENTRY*
研究二维空间中的伯特兰价格竞争，发现街区度量下正方形市场区域的价格远低于菱形区域；需求密度增长会引发进入浪潮，市场形状在正方形与菱形间交替变化。
ABSTRACT This paper examines two‐dimensional spatial competition, with Bertrand price determination. With a block metric, equilibrium prices are significantly lower when market areas are squares than when they are diamonds (rotated squares) of the same size. If demand density grows, waves of entry occur, and the shapes of market areas change from squares to diamonds and back to squares again. The former change leaves prim unchanged, whereas the latter cuts prices in half. Results are also derived for a Euclidean metric, with square and hexagonal market areas. Optimal waves of entry are examined with the block metric. With either metric, the socially optimal market shape becomes suboptimal if market areas are constrained to be of the zero‐profit size.