A Boolean Matrix Method for the Computation
of Linear Precedence Functions
A modified version of Bell's Boolean matrix
method for the computation of linear precedence 
functions associated with a conflict-free matrix of
precedence relations is given.  This algorithm not 
only detects when the precedence functions do not  exist,
but also provides an indication of why they 
do not exist, so that corrective action can be taken
if possible.  Necessary and sufficient conditions 
for the existence of precedence functions are given.
 The use of Boolean matrices to prove the existence 
of precedence functions associated with classes of conflict-free
grammars is illustrated through an example.
CACM June, 1972
Martin, D. F.
