Converge

In a metric space (X, d), a sequence <math> a_n</math> in X is said to converge to a point <math>x</math> if roughly speaking as <math> n </math> goes to infinity <math> a_n</math> gets closer and closer to <math>x</math> and stays there. Rigorously, <math> a_n</math> is said to converge to <math>x</math> if for all <math>\epsilon>0</math> there exists N such that for all n > N we have <math>d\left (a_n, x\right ) < \epsilon </math>.

Similar definitions can be made for convergence of functions.