The following discussion from !1546 should be addressed: - [ ] @timok started a [discussion](https://git.iws.uni-stuttgart.de/dumux-repositories/dumux/merge_requests/1546#note_28434): > I think has resize is also needed in other places. Theoretically we can just use a copy of https://web.math.pmf.unizg.hr/nastava/nrpdj/DuneDoc/release-2.6.1/dune-functions/doc/doxygen/html/a01948_source.html > the implementation in dune functions and put it e.g. in dumux/common/concepts.hh Also some other tiny "concepts" might be useful, however usually it's not real concepts so we should be careful.