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  2. Sphere eversion - Wikipedia

    en.wikipedia.org/wiki/Sphere_eversion

    An existence proof for crease-free sphere eversion was first created by Stephen Smale ().It is difficult to visualize a particular example of such a turning, although some digital animations have been produced that make it somewhat easier.

  3. List of knapsack problems - Wikipedia

    en.wikipedia.org/wiki/List_of_knapsack_problems

    The knapsack problem is one of the most studied problems in combinatorial optimization, with many real-life applications. For this reason, many special cases and generalizations have been examined. For this reason, many special cases and generalizations have been examined.

  4. Inverse problem - Wikipedia

    en.wikipedia.org/wiki/Inverse_problem

    An inverse problem in science is the process of calculating from a set of observations the causal factors that produced them: for example, calculating an image in X-ray computed tomography, source reconstruction in acoustics, or calculating the density of the Earth from measurements of its gravity field. It is called an inverse problem because ...

  5. Calculus of variations - Wikipedia

    en.wikipedia.org/wiki/Calculus_of_Variations

    Calculus of variations is concerned with variations of functionals, which are small changes in the functional's value due to small changes in the function that is its argument. The first variation [l] is defined as the linear part of the change in the functional, and the second variation [m] is defined as the quadratic part. [22]

  6. Stefan problem - Wikipedia

    en.wikipedia.org/wiki/Stefan_problem

    The Stefan problem also has a rich inverse theory; in such problems, the melting depth (or curve or hyper-surface) s is the known datum and the problem is to find u or f. [ 14 ] Advanced forms of Stefan problem

  7. Inverse curve - Wikipedia

    en.wikipedia.org/wiki/Inverse_curve

    In inversive geometry, an inverse curve of a given curve C is the result of applying an inverse operation to C. Specifically, with respect to a fixed circle with center O and radius k the inverse of a point Q is the point P for which P lies on the ray OQ and OP·OQ = k 2. The inverse of the curve C is then the locus of P as Q runs over C.

  8. Bounded variation - Wikipedia

    en.wikipedia.org/wiki/Bounded_variation

    It can be proved that a real function is of bounded variation in [,] if and only if it can be written as the difference = of two non-decreasing functions and on [,]: this result is known as the Jordan decomposition of a function and it is related to the Jordan decomposition of a measure.

  9. Inverse function - Wikipedia

    en.wikipedia.org/wiki/Inverse_function

    In mathematics, the inverse function of a function f (also called the inverse of f) is a function that undoes the operation of f. The inverse of f exists if and only if f is bijective , and if it exists, is denoted by f − 1 . {\displaystyle f^{-1}.}