  Decreasing impatience, a common behavioral phenomenon in intertemporal
choice, and a property with certain normative support in the literature on
project evaluation, is characterized in several different ways. Discount
factors that display decreasing impatience are characterized through a
convexity axiom for investments at fixed interest rates. Then we show that they
are equivalent to a geometric average of generalized quasi-hyperbolic discount
rates. Finally, they emerge as prices in parimutuel betting markets, that is as
the outcome of parimutuel aggregation.
