In this paper we finished the project of classifying
compact solvmanifold with a symplectic structure by symplectic reductions and extentions. Especially, we  
found many nilmanifolds of this type has a nilponent Lie group as the universal covering
such that the Lie group has more than two steps as a solvable Lie group.
(Abstract posted on Sept. 1, 2009) 
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1991 Mathematics Subject Classification: 57R17, 57R19, 57S25,
57S30, 22E25