An Improved Equivalence Algorithm
An algorithm for assigning storage on the basis
of EQUIVALENCE, DIMENSION and COMMON declarations 
is presented.  The algorithm is based on a tree structure,
and has reduced computation time by 40 percent 
over a previously published algorithm by identifying all
equivalence classes with one scan of the EQUIVALENCE 
declarations.  The method is applicable in any problem
in which it is necessary to identify equivalence 
classes, given the element pairs defining the equivalence relation.
CACM May, 1964
Galler, B. A.
Fisher, M. J.
