We give an algebraic characterization of a form of synchronized parallel
composition allowing for true concurrency, using ideas based on Peter Landin's
"Program-Machine Symmetric Automata Theory".Comment: This is an old technical report from 1981. I submitted it to a
special issue of HOSC in honour of Peter Landin, as explained in the Prelude,
added in 2008. However, at an advanced stage, the handling editor became
unresponsive, and the paper was never published. I am making it available via
the arXiv for the same reasons given in the Prelud