A canonical process for estimation of convex functions: the “invelope” of integrated Brownian motion + t
نویسندگان
چکیده
A process associated with integrated Brownian motion is introduced that characterizes the limit behavior of nonparametric least squares and maximum likelihood estimators of convex functions and convex densities, respectively. We call this process “the invelope” and show that it is an almost surely uniquely defined function of integrated Brownian motion. Its role is comparable to the role of the convex minorant of Brownian motion + a parabolic drift in problem of estimating monotone functions. An iterative cubic spline algorithm is introduced that solves the contrained least squares problem in the limit situation and some results, obtained by applying this algorithm, are shown to illustrate the theory. 1 Research supported in part by National Science Foundation grant DMS-95-32039, NIAID grant 2R01 AI29196804, and the Stieltjes Institute AMS 2000 subject classifications. Primary: 62G05; secondary 60G15, 62E20.
منابع مشابه
A canonical process for estimation of convex functions: the "invelope" of integrated Brownian motion + t^4
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