The Hard Lefschetz theorem for nonrational polytopes -- 
Kalle Karu, Oct. 11, 2002

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The Hard Lefschetz theorem is known to hold for the intersection 
cohomology of the toric variety associated to a rational convex 
polytope. One can construct the intersection cohomology combinatorially 
from the polytope, hence it is well defined even for a nonrational 
polytope when there is no variety associated to it. The talk is about 
the Hard Lefschetz theorem for the intersection cohomology of a general 
polytope.