1 . FREE MOVEMENT OF PERSONS - WORKER - CONCEPT - EXISTENCE OF AN EMPLOYMENT RELATIONSHIP - TRAINEE TEACHER - INCLUDED ( EEC TREATY , ART . 48 ( 1 )) 2 . FREE MOVEMENT OF PERSONS - DEROGATIONS - EMPLOYMENT IN THE PUBLIC SERVICE - CONCEPT - PARTICIPATION IN THE EXERCISE OF POWERS CONFERRED BY PUBLIC LAW AND IN THE SAFEGUARDING OF THE GENERAL INTERESTS OF THE STATE - TRAINEE TEACHER ( EEC TREATY , ART . 48 ( 4 ))