Machine Learning Necessary for Deep Learning

In another article, we touched a bit on generalization. What is the relationship between the generalization error and the training error? Generalization is the concept of the machine learning algorithm being able to produce good predictions on previously unseen inputs. The red line represents the training error. If the horizontal axis is the quantity of training examples or time, depending on how you like to think about it, then with time this training error gets smaller and smaller.