  We describe a mathematical structure that can give extensional denotational
semantics to higher-order probabilistic programs. It is not limited to discrete
probabilities, and it is compatible with integration in a way the models that
have been proposed before are not. It is organised as a model of propositional
linear logic in which all the connectives have intuitive probabilistic
interpretations. In addition, it has least fixed points for all maps, so it can
interpret recursion.
