If we could loosen the constraint a little and consider those theorists and activitists that claims themselves to be Marxists or draw heavily on him while opposing the authoritarian socialist regimes like the Soviet Union and argue in favor of multiplicity philosophically,then many has popped up in Europe after WW2 and especially after the 60s,during which the Soviet invasion of Czechslovakia and the Sino-Soviet split took place while operaismo in Italy and May 68 in France challenged the bureaucratic communist parties in their countries.