Set Theory Foundation A Branch of Math- of Math- ematics ematies (Loglc) (a,b) A→B N,R ) AxB RC AxB Hengfeng Wei (bfweiinju.edu.cn1-10 Set Theory (III:Functions 2019年12月10日2/40Set Theory A Branch of Math￾ematics N, R ℵ0 ω Foundation of Math￾ematics (+ Logic) (a, b) {} A × B R ⊆ A × B f : A → B Hengfeng Wei (hfwei@nju.edu.cn) 1-10 Set Theory (III): Functions 2019 年 12 月 10 日 2 / 40