Algorithms of Recommender Systems ⟨ http://www.kamishima.net/ ⟩ Release: 2016-09-26 21:53:16 +0900; 9645c3b i 2007 11 [ 07] 2008 1 [ 08a] 2008 3 [ 08b] 3 (1) (3) GitHub https://github.com/tkamishima/recsysdoc TYPO GitHub pull request issues I II III IV V ii J. Riedl J. Herlocker GroupLens WWW iii 𝑥 𝑋 𝐱 𝐗 𝑥 𝑦 𝑋 𝑌 𝐱 𝐲 𝑛 𝑚 {1, … , 𝑛} {1, … , 𝑚} 𝑦 𝑦 𝑥 x 𝑎 𝑟𝑥𝑦 𝑥 𝑦 ̄ 𝑟𝑥
