Process algebra reconsidered

Paper is here.
The following incorrect claim is not unusual in the process algebra literature.

Basically, what is missing [in classical automata theory] is the notion of interaction: during the execution from initial state to fi nal state, a system may interact with another system. This is needed in order to describe parallel or distributed systems, or so-called reactive systems. When dealing with interacting systems, we say we are doing concurrency theory, so concurrency theory is the theory of interacting, parallel and/or distributed systems.[Bae05]

Actually a sophisticated notion of state machine product was developed for representing composition of “interacting” state machines starting in the 1950s[HS66]. A general survey can be found in a monograph by Gecseg[Gec86], Domosi provides a more modern, more algebraic treatment [DN04] and [Yod09] provides practical techniques for construction of complex products.
The reader familiar with the process algebra literature will note that such an e ffort must find a way to model the non-determinism that is so fundamental to the process algebra world-view. Since deterministic programs are used to produce pseudo-random number sequences and to model Brownian motion and even the stock market (perhaps not the best example at this date) the problem is easier to solve than it appears at fi rst. Section 4 will include a short discussion on the diff erence between “real” non-determinism and simulated non-determinism, but certainly there is nothing in the basic axiom set of Milner’s original process algebra that notices this distinction as far as I can see.

To read more see the paper.

R.L. Moore topologist and racist

If you read this down to the bottom you get a little hint, but you have to read something like this to understand what that little hint means.

In graduate school she was very much alone, though she was a grader for an undergraduate course taken by Raymond Johnson. In her first class, she was the only Black, the only woman. Her classmates ignored her completely, even terminating conversations if she came within earshot. She was denied a teaching assistantship, although she was an experienced (13 years) and excellent teacher. She wrote further:”I could not join my advisor and other classmates to discuss mathematics over coffee at Hilsberg’s cafe…. Hilsberg’s would not serve Blacks. Occasionally, I could get snatches of their conversation as they crossed our picket line outside the cafe.” She could not enroll in professor R.L. Moore class as he explicitly stated that he did not teach Blacks. Overlooking all this, one of her professors, complaining against the civil rights demonstrations, said to her: “If all those out there were like you, hard-working and studious, we wouldn’t have any problems.” Her reply: “If it hadn’t been for those hell-raisers out there, you wouldn’t even know me.”