The notion of a U-statistic for an n-tuple of identical quantum systems is introduced inanalogy to the classical (commutative) case: given a selfadjoint ‘kernel’ K acting on (Cd)rwith r n, we define the symmetric operator Un = ??nrP K() with K() being the kernelacting on the subset of {1, ....

The aim of this article is to evaluate the effect of the cost of R&D capital, and more particularly of the taxcredit on R&D expenditures, introduced in France since 1983, as a fiscal incentive to private R&D. A user cost of R&Dcapital is derived with imperfect capital markets, corporate and...

We consider a general equilibrium model under imperfect competition. Firms have constantreturns, they are price taker in the input market and compete à la Cournot in theproduct market. We assume a representative consumer exists. We show that an increase inthe number of firms of a given market...