Minority Report (film) Spielberg also offered the role of Witwer to Javier Bardem, who turned it down. After "E.T.", Spielberg started to consult experts, and put more scientific research into his science fiction films. In 1999, he invited fifteen experts convened by Peter Schwartz and Stewart Brand to a hotel in Santa Monica for a three-day "think tank". He wanted to consult with the group to create a plausible "future reality" for the year 2054 as opposed to a more traditional "science fiction" setting. Dubbed the "think tank summit", the experts included architect Peter Calthorpe, author Douglas Coupland, urbanist and journalist Joel Garreau,
Directed set this article) assume that a directed set is directed upward, unless otherwise stated. Beware that other authors call a set directed if and only if it is directed both upward and downward. Directed sets are a generalization of nonempty totally ordered sets. That is, all totally ordered sets are directed sets (contrast "partially" ordered sets, which need not be directed). Join semilattices (which are partially ordered sets) are directed sets as well, but not conversely. Likewise, lattices are directed sets both upward and downward. In topology, directed sets are used to define nets, which generalize sequences and unite the various