The bakery algorithm: yet another specification and verification

In a meeting at Schloss Dagstuhl in June 1993, Uri Abraham and Menachem Magidor have challenged the thesis that an evolving algebra can be tailored to any algorithm at its own abstraction level. As example they gave an instructive proof which uses lower and higher views to show correctness of Lamport’s bakery algorithm. We construct two evolving algebras capturing lower and higher view respectively, enabling a simple and concise proof of correctness for the bakery algorithm.