title: Editorial introduction.
authors.affiliation: Mathematical Institute, Leiden University, P.O. Box 9512, 2300 RA Leiden, The Netherlands. Electronic address: shota.gugushvili@math.leidenuniv.nl.
authors.forename: Shota
authors.initials: S
authors.lastname: Gugushvili
authors.forename: Chris A J
authors.initials: CA
authors.lastname: Klaassen
authors.forename: Aad W
authors.initials: AW
authors.lastname: van der Vaart
mesh_terms: D008433:Mathematics / Q000379:methods*