In short - these slides are missleading. You can treat the binary classification as multi-label classification and so no additional restrictions apply. However, the trick with X x Y -> F is simply redundant in binary classification. As here everything that gives you any information about classifing to class 0
gives you information about classification to class 1
also (as there is no other option, only two possibilities), while in multi class scenario not being a part of class 0
gives you no actual information (it can still be the part of class 2
or k
) so there is a reason behind defining features just for some classes. To sum up:
- Despite what is written in these slides you can treat binary classification as multi-class one
- Using X x Y -> F mapping in binary classification is redundant