Dr Szabolcs Mikulas / Research / Permutation Model
Permutation Model
Here is the "artist's" impression of a permutation model, see [HMT] 3.2.68, which shows that not every abstract diagonal-free cylindric algebra of dimension three is representable. This model satisfies the Church-Rosser property and commutativity of the cylindrifications, but the "cubifying" equation does not hold.