Most important part of a ML system is the learning element. Spam filter: learning element has figured out which words indicate something is spam. Usually starts from some training set, adjusted by “report spam” button.
Explain basic example of training and testing sets Explain basic idea of a classifier
The algorithm may not return the same tree, but it will return a tree that is logically equivalent, assuming that the method for generating the training set eventually generates all possible combinations of attributes. For example, if the method picks the value of each attribute uniformly at random, the probability that it generates all possible combinations goes to one when the training set goes to infinity. The form of the tree may not be the same, because there are multiple ways of representing the same logical function.