Abstract. We construct all planar semimodular lattices in three simple steps from the direct product of two chains.

AMS Subject Classification (1991): 06C10, 06D05

Keyword(s): Semimodular lattice, planar, distributive, modular

Received November 28, 2006, and in revised form February 10, 2007. (Registered under 6445/2009.)