Question Description

Show that if A is an open set in R^p and x in A, then there exists a number r > 0 such that the closed ball { y in R : || x -y || <= r } is contained in A.

Show that if A is an open set in R^p and x in A, then there exists a number r > 0 such that the closed ball { y in R : || x -y || <= r } is contained in A.