Code properties of minimal generating sets of retracts and semiretracts
Let \(A\) be a finite set and \(A^*\) be the free monoid on \(A\). A retract of \(A^*\) is a submonoid of \(A^*\) which is the image of an idempotent homomorphism from \(A^*\) to \(A^*\). A semiretract of \(A^*\) is the intersection of a family of retracts of \(A^*\). In the paper a survey is given of code properties of the minimal generating set of retracts and semiretracts. These are then used to prove properties of syntactic monoids of retracts and semiretracts.
scientific article; zbMATH DE number 733171