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  2. Radon transform - Wikipedia

    en.wikipedia.org/wiki/Radon_transform

    Radon transform. Maps f on the (x, y)-domain to Rf on the (α, s)-domain.. In mathematics, the Radon transform is the integral transform which takes a function f defined on the plane to a function Rf defined on the (two-dimensional) space of lines in the plane, whose value at a particular line is equal to the line integral of the function over that line.

  3. Tomographic reconstruction - Wikipedia

    en.wikipedia.org/wiki/Tomographic_reconstruction

    In theory, the inverse Radon transformation would yield the original image. The projection-slice theorem tells us that if we had an infinite number of one-dimensional projections of an object taken at an infinite number of angles, we could perfectly reconstruct the original object, f ( x , y ) {\displaystyle f(x,y)} .

  4. Penrose transform - Wikipedia

    en.wikipedia.org/wiki/Penrose_transform

    The "twistor space" Z is complex projective 3-space CP 3, which is also the Grassmannian Gr 1 (C 4) of lines in 4-dimensional complex space. X = Gr 2 (C 4), the Grassmannian of 2-planes in 4-dimensional complex space. This is a compactification of complex Minkowski space. Y is the flag manifold whose elements correspond to a line in a plane of C 4.

  5. Integral geometry - Wikipedia

    en.wikipedia.org/wiki/Integral_geometry

    In mathematics, integral geometry is the theory of measures on a geometrical space invariant under the symmetry group of that space. In more recent times, the meaning has been broadened to include a view of invariant (or equivariant) transformations from the space of functions on one geometrical space to the space of functions on another geometrical space.

  6. List of unsolved problems in mathematics - Wikipedia

    en.wikipedia.org/wiki/List_of_unsolved_problems...

    Many mathematical problems have been stated but not yet solved. These problems come from many areas of mathematics, such as theoretical physics, computer science, algebra, analysis, combinatorics, algebraic, differential, discrete and Euclidean geometries, graph theory, group theory, model theory, number theory, set theory, Ramsey theory, dynamical systems, and partial differential equations.

  7. Funk transform - Wikipedia

    en.wikipedia.org/wiki/Funk_transform

    In the mathematical field of integral geometry, the Funk transform (also known as Minkowski–Funk transform, Funk–Radon transform or spherical Radon transform) is an integral transform defined by integrating a function on great circles of the sphere. It was introduced by Paul Funk in 1911, based on the work of Minkowski (1904).

  8. Lebesgue–Stieltjes integration - Wikipedia

    en.wikipedia.org/wiki/Lebesgue–Stieltjes...

    The Lebesgue–Stieltjes integral ()is defined when : [,] is Borel-measurable and bounded and : [,] is of bounded variation in [a, b] and right-continuous, or when f is non-negative and g is monotone and right-continuous.

  9. Riesz–Markov–Kakutani representation theorem - Wikipedia

    en.wikipedia.org/wiki/Riesz–Markov–Kakutani...

    As such, if all open sets in X are σ-compact then is a Radon measure. [2] One approach to measure theory is to start with a Radon measure, defined as a positive linear functional on C c (X). This is the way adopted by Bourbaki; it does of course assume that X starts life as a topological space, rather than simply as a set. For locally compact ...