Haskellians, i've found a way to generalize the LogicT transformer and calculated it's application to three fairly interesting examples. The approach -- with some sample codes as scala+lift web apps -- is described herehttp://biosimilarity.blogspot.com/2009/01/3-applications-of-indexed-composit.... Comments welcome. Best wishes, --greg -- L.G. Meredith Managing Partner Biosimilarity LLC 806 55th St NE Seattle, WA 98105 +1 206.650.3740 http://biosimilarity.blogspot.com