/// <summary>
/// Returns the set of all Things in the session, except two specific Things.
/// </summary>
public static Tset peopleBut(Thing p1, Thing p2)
{
return(Facts.AllKnownPeople() - p1 - p2);
}
/// <summary>
/// Returns the set of all Things in the session.
/// </summary>
public static Tset people()
{
return(Facts.AllKnownPeople());
}