Reduction: A Method of Proving Properties of Parallel Programs
When proving that a parallel program has a
given property it is often convenient to assume 
that a statement is indivisible, i.e. that the statement
cannot be interleaved with the rest of the program. 
 Here sufficient conditions are obtained to show that
the assumption that a statement is indivisible 
can be relaxed and still preserve properties such as
halting.  Thus correctness proofs of a parallel 
system can often be greatly simplified.
CACM December, 1975
Lipton, R. J.
