Generating Order 2 and 4 Free-Fermionic NAHE-Based Heterotic Models

Starting with a short overview of string phenomenology we then motivate our search of the free-fermionic heterotic string models. We generate all possible order 2 and 4 boundary vectors which can be added to the NAHE set and still form a consistent MSSM string model. We discuss briefly how they are generated and how they are used to study the corresponding gauge groups.