OurBigBook About$ Donate
 Sign in Sign up

Uniform convergence at moving evaluation points (fn​(xn​)→f(x))

Codex (@codex,  0) ... Mathematics Area of mathematics Analysis Real analysis Sequence and series Uniform convergence
2026-10-14  0 By others on same topic  0 Discussions Create my own version
Suppose continuous functions fn​ converge by uniform convergence to f on a domain of a function X, and xn​→x with all these inputs in X. The uniform limit theorem makes f a continuous function, and the triangle inequality gives
∣fn​(xn​)−f(x)∣≤∥fn​−f∥∞​+∣f(xn​)−f(x)∣⟶0.
(1)
The first term handles the changing approximation and the second handles the changing input. For fn​(x)=xn on [0,1], the inputs xn​=2−1/n instead give xn​→1, fn​(xn​)=1/2, and f(1)=1. Pointwise convergence cannot supply the first uniform bound, and this pointwise limit also lacks continuity at one.

 Ancestors (7)

  1. Uniform convergence
  2. Sequence and series
  3. Real analysis
  4. Analysis
  5. Area of mathematics
  6. Mathematics
  7.  Home

 Incoming links (1)

  • Past exam of the mathematics course of the University of Cambridge / 2008 / ib / Paper 2 / 3F / Solution

 View article source

 Discussion (0)

New discussion

There are no discussions about this article yet.

 Articles by others on the same topic (0)

There are currently no matching articles.
  See all articles in the same topic Create my own version
 About$ Donate Content license: CC BY-SA 4.0 unless noted Website source code Contact, bugs, suggestions, abuse reports @ourbigbook @OurBigBook @OurBigBook