  The iTWIST workshop series aim at fostering collaboration between
international scientific teams for developing new theories, applications and
generalizations of low-complexity models. These events emphasize dissemination
of ideas through both specific oral and poster presentations, as well as free
discussions. For this fourth edition, iTWIST'18 gathered in CIRM, Marseille,
France, 74 international participants and featured 7 invited talks, 16 oral
presentations, and 21 posters.
  From iTWIST'18, the scientific committee has decided that the workshop
proceedings will adopt the episcience.org philosophy, combined with arXiv.org:
in a nutshell, "the proceedings are equivalent to an overlay page, built above
arXiv.org; they add value to these archives by attaching a scientific caution
to the validated papers."
  This means that all papers listed in the HTML page of this arxiv publication
(see the menu on the right) have been thoroughly evaluated and approved by two
independent reviewers, and authors have revised their work according to the
comments provided by these reviewers.
