  The syntactic Merge operation of the Minimalist Program in linguistics can be
described mathematically in terms of Hopf algebras, with a formalism similar to
the one arising in the physics of renormalization. This mathematical
formulation of Merge has good descriptive power, as phenomena empirically
observed in linguistics can be justified from simple mathematical arguments. It
also provides a possible mathematical model for externalization and for the
role of syntactic parameters.
