Convex Set Definition 2(Ball).A(Euclidean)ball (or just ball)in Rd has the form B(xc;r)={xc+ruull2 <1}. Definition 3(Ellipsoids).A ellipsoid in Rd has the form E(xe,A)={xe+Au|Iu‖2≤1}， where A is assumed to be symmetric and positive definite. Au Advanced Optimization(Fall 2023) Lecture 2.Convex Optimization Basics 9 Advanced Optimization (Fall 2023) Lecture 2. Convex Optimization Basics 9 Convex Set