An Efficient Procedure for the Generation of Closed Subsets
An efficient algorithm is described for generating
subsets of a set S which satisfy constraints 
of the form: "If s(i) is a member of the subset, then
s(j) must also be a member of the subset."  The 
algorithm has been programmed in the WISP language and
successfully run on the IBM 7094 in connection 
with a routine to detect feedback in multidimensional iterative networks.
CACM March, 1967
Waite, W. M.
