simply supervised learning you train this network in a supervised fashion on that small fraction of data that has class labels and that already performs pretty well and they show this in experiments but then you can go a step further and do what's known as distillation or self-training and what's distillation or self-training it's so distillation is when you have a network that you call the teacher Network and that network has been trained to do some classification maybe into three classes pretty pretty well okay but now this is