Introduction Many Web-mining problems can be expressed as finding "similar"sets: 1.Pages with similar words,e.g.,for classification by topic. 2.NetFlix users with similar tastes in movies,for recommendation systems. 3.Movies with similar sets of fans. 4.Images of related things. 99 Many Web-mining problems can be expressed as finding “similar” sets: 1. Pages with similar words, e.g., for classification by topic. 2. NetFlix users with similar tastes in movies, for recommendation systems. 3. Movies with similar sets of fans. 4. Images of related things. Introduction Introduction