then this down here they want to be far apart Zi with Z K where K is all the other images okay you can do this in a mini-batch fashion so this is self supervised learning and the reason why you do this is you don't need labels and it tends we know it tends to give very very good representations so um pass that so what this network here will learn will be very good representation with these self supervised loss with contrastive loss for example gives such good performance there have been papers recently that modify the loss and so on