2005/05/19 by Dmitry Rokhlin, Rokhlin, Dmitry, Walter Schachermayer +1
Mathematics · #46E30 #FOS: Mathematics #Functional Analysis (math.FA) #math.FA #msc:46E30
paper · pdf · doi:10.48550/arxiv.math/0505411
9 pages
arxiv created 2005/05/19 · arxiv updated 2009/12/01
For a given element f∈ L1 and a convex cone C⊂ L^∞, C∩ L^∞+=\0\ we give necessary and sufficient conditions for the existence of an element g≥ f lying in the polar of C. This polar is taken in (L^∞)^* and in L1. In the context of mathematical finance the main result concerns the existence of martingale measures, whose densities are bounded from below by prescribed random variable.