Partial Functions, Minimization, and PCF without the Mystery in Scala

If this article doesn’t terminate, at least the total attraction does after midnight.

This article distills all concepts related to partial recursive functions, the mu operator, and PCF into a compact guide as I teach it in my class on Programming Language Design and Implementation based on Prof. Harper’s textbook. The aim is to keep the language plain, the structure clean, and the Scala examples ready to paste into your notes or code files. When we write small programs that sometimes never finish, we are not being sloppy. We are modeling real computation in Scala.