f:A→B g:C→D Q:lsf∩g a function? Theorem (Intersection of Functions) fng:(A∩C)→(BnD) Hengfeng Wei (hfweinju.edu.cn)1-10 Set Theory (III):Functions: 2019年12月10日14/40f : A → B g : C → D Q : Is f ∩ g a function? Theorem (Intersection of Functions) f ∩ g : (A ∩ C) → (B ∩ D) Hengfeng Wei (hfwei@nju.edu.cn) 1-10 Set Theory (III): Functions 2019 年 12 月 10 日 14 / 40