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  2. Kakutani fixed-point theorem - Wikipedia

    en.wikipedia.org/wiki/Kakutani_fixed-point_theorem

    The Kakutani fixed point theorem is a generalization of the Brouwer fixed point theorem. The Brouwer fixed point theorem is a fundamental result in topology which proves the existence of fixed points for continuous functions defined on compact, convex subsets of Euclidean spaces. Kakutani's theorem extends this to set-valued functions.

  3. Fixed-point theorem - Wikipedia

    en.wikipedia.org/wiki/Fixed-point_theorem

    The Banach fixed-point theorem (1922) gives a general criterion guaranteeing that, if it is satisfied, the procedure of iterating a function yields a fixed point. [2]By contrast, the Brouwer fixed-point theorem (1911) is a non-constructive result: it says that any continuous function from the closed unit ball in n-dimensional Euclidean space to itself must have a fixed point, [3] but it doesn ...

  4. Ryll-Nardzewski fixed-point theorem - Wikipedia

    en.wikipedia.org/wiki/Ryll-Nardzewski_fixed...

    In functional analysis, a branch of mathematics, the Ryll-Nardzewski fixed-point theorem states that if is a normed vector space and is a nonempty convex subset of that is compact under the weak topology, then every group (or equivalently: every semigroup) of affine isometries of has at least one fixed point. (Here, a fixed point of a set of ...

  5. Caristi fixed-point theorem - Wikipedia

    en.wikipedia.org/wiki/Caristi_fixed-point_theorem

    In mathematics, the Caristi fixed-point theorem (also known as the Caristi–Kirk fixed-point theorem) generalizes the Banach fixed-point theorem for maps of a complete metric space into itself. Caristi's fixed-point theorem modifies the ε {\displaystyle \varepsilon } - variational principle of Ekeland (1974, 1979).

  6. Lawvere's fixed-point theorem - Wikipedia

    en.wikipedia.org/wiki/Lawvere's_fixed-point_theorem

    In mathematics, Lawvere's fixed-point theorem is an important result in category theory. [1] It is a broad abstract generalization of many diagonal arguments in mathematics and logic, such as Cantor's diagonal argument, Cantor's theorem, Russell's paradox, Gödel's first incompleteness theorem, Turing's solution to the Entscheidungsproblem, and Tarski's undefinability theorem.

  7. Fixed-point theorems in infinite-dimensional spaces - Wikipedia

    en.wikipedia.org/wiki/Fixed-point_theorems_in...

    Schauder fixed-point theorem: Let C be a nonempty closed convex subset of a Banach space V. If f : C → C is continuous with a compact image, then f has a fixed point. Tikhonov (Tychonoff) fixed-point theorem: Let V be a locally convex topological vector space. For any nonempty compact convex set X in V, any continuous function f : X → X has ...

  8. Category:Fixed-point theorems - Wikipedia

    en.wikipedia.org/wiki/Category:Fixed-point_theorems

    Banach fixed-point theorem; Bekić's theorem; Blackwell's contraction mapping theorem; Borel fixed-point theorem; Borsuk–Ulam theorem; Bourbaki–Witt theorem; Brouwer fixed-point theorem; Browder fixed-point theorem; Bruhat–Tits fixed point theorem

  9. Fixed-point computation - Wikipedia

    en.wikipedia.org/wiki/Fixed-point_computation

    Fixed-point computation refers to the process of computing an exact or approximate fixed point of a given function. [1] In its most common form, the given function f {\displaystyle f} satisfies the condition to the Brouwer fixed-point theorem : that is, f {\displaystyle f} is continuous and maps the unit d -cube to itself.