Under heightened security due to the fear of riots by November 17 sympathizers, three days of commemoration opened at the Athens Polytechnic yesterday for the 1973 student revolt that inspired the left-wing terrorist group’s name. Celebrations were focused on the Patission Street complex – now known as the National Technical University of Athens – where military forces on November 17, 1973, violently put down a student pro-democracy protest, using a tank to knock down the gates. It is still unclear how many people died in the crackdown. In a statement yesterday, the ruling Socialist party spoke of the government’s success in catching the N17 terrorists «without constricting civil liberties.» Fears that N17 sympathizers, as well as anarchists and left-wingers, could hijack the Polytechnic celebrations to protest against the terror suspects’ detention conditions have spurred the government to lay on 5,000 policemen for tomorrow’s 3 p.m. march to the US Embassy. Public transport schedules will be altered today and tomorrow, while the E95 airport express from Syntagma will not run from 2 p.m. today to 11 p.m. tomorrow. But the E94 from Ethniki Amyna Metro station will.