enow.com Web Search

  1. Ad

    related to: can continuous functions have holes in back of roof

Search results

  1. Results from the WOW.Com Content Network
  2. Closed graph property - Wikipedia

    en.wikipedia.org/wiki/Closed_graph_property

    Let X denote the real numbers ℝ with the usual Euclidean topology and let Y denote ℝ with the indiscrete topology (where note that Y is not Hausdorff and that every function valued in Y is continuous). Let f : X → Y be defined by f(0) = 1 and f(x) = 0 for all x ≠ 0. Then f : X → Y is continuous but its graph is not closed in X × Y. [4]

  3. Closed graph theorem - Wikipedia

    en.wikipedia.org/wiki/Closed_graph_theorem

    So, if the open mapping theorem holds for ; i.e., is an open mapping, then is continuous and then is continuous (as the composition of continuous maps). For example, the above argument applies if f {\displaystyle f} is a linear operator between Banach spaces with closed graph, or if f {\displaystyle f} is a map with closed graph between compact ...

  4. Brouwer fixed-point theorem - Wikipedia

    en.wikipedia.org/wiki/Brouwer_fixed-point_theorem

    Every continuous function from a closed disk to itself has at least one fixed point. [6] This can be generalized to an arbitrary finite dimension: In Euclidean space Every continuous function from a closed ball of a Euclidean space into itself has a fixed point. [7] A slightly more general version is as follows: [8] Convex compact set

  5. Common fixed point problem - Wikipedia

    en.wikipedia.org/wiki/Common_fixed_point_problem

    Taking a different approach, Haskell Cohen showed in 1964 that and will have a common fixed point if both are continuous and open. [8] Later, both Jon H. Folkman and James T. Joichi, working independently, extended Cohen's work, showing that it is only necessary for one of the two functions to be open. [9] [10]

  6. Continuous function - Wikipedia

    en.wikipedia.org/wiki/Continuous_function

    the sinc-function becomes a continuous function on all real numbers. The term removable singularity is used in such cases when (re)defining values of a function to coincide with the appropriate limits make a function continuous at specific points. A more involved construction of continuous functions is the function composition.

  7. Tietze extension theorem - Wikipedia

    en.wikipedia.org/wiki/Tietze_extension_theorem

    Pavel Urysohn. In topology, the Tietze extension theorem (also known as the Tietze–Urysohn–Brouwer extension theorem or Urysohn-Brouwer lemma [1]) states that any real-valued, continuous function on a closed subset of a normal topological space can be extended to the entire space, preserving boundedness if necessary.

  8. Closed graph theorem (functional analysis) - Wikipedia

    en.wikipedia.org/wiki/Closed_graph_theorem...

    The usual proof of the closed graph theorem employs the open mapping theorem.It simply uses a general recipe of obtaining the closed graph theorem from the open mapping theorem; see closed graph theorem § Relation to the open mapping theorem (this deduction is formal and does not use linearity; the linearity is needed to appeal to the open mapping theorem which relies on the linearity.)

  9. Uniform continuity - Wikipedia

    en.wikipedia.org/wiki/Uniform_continuity

    The Heine–Cantor theorem asserts that every continuous function on a compact set is uniformly continuous. In particular, if a function is continuous on a closed bounded interval of the real line, it is uniformly continuous on that interval. The Darboux integrability of continuous functions follows almost immediately from this theorem.

  1. Ad

    related to: can continuous functions have holes in back of roof