402.3B5 (Finite) Unions and Intersections of Open Sets

Getting new open sets from old requires us to investigate both whether and when the union and intersection of a collection of open sets is an open set. See the playlist: http://matthematics.com/real 0:00 Introduction 1:24 The Union of Two Open Sets is Open 4:07 The Intersection of Two Open Sets is Open 8:06 Induction: Two Implies Any Finite Number