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  2. Scale invariance - Wikipedia

    en.wikipedia.org/wiki/Scale_invariance

    In physical cosmology, the power spectrum of the spatial distribution of the cosmic microwave background is near to being a scale-invariant function. Although in mathematics this means that the spectrum is a power-law, in cosmology the term "scale-invariant" indicates that the amplitude, P ( k ) , of primordial fluctuations as a function of ...

  3. Scale-invariant feature transform - Wikipedia

    en.wikipedia.org/wiki/Scale-invariant_feature...

    Alternative methods for scale-invariant object recognition under clutter / partial occlusion include the following. RIFT [38] is a rotation-invariant generalization of SIFT. The RIFT descriptor is constructed using circular normalized patches divided into concentric rings of equal width and within each ring a gradient orientation histogram is ...

  4. Power law - Wikipedia

    en.wikipedia.org/wiki/Power_law

    This property of () follows directly from the requirement that () be asymptotically scale invariant; thus, the form of () only controls the shape and finite extent of the lower tail. For instance, if L ( x ) {\displaystyle L(x)} is the constant function, then we have a power law that holds for all values of x {\displaystyle x} .

  5. Self-similarity - Wikipedia

    en.wikipedia.org/wiki/Self-similarity

    Scale invariance is an exact form of self-similarity where at any magnification there is a smaller piece of the object that is similar to the whole. For instance, a side of the Koch snowflake is both symmetrical and scale-invariant; it can be continually magnified 3x without changing shape. The non-trivial similarity evident in fractals is ...

  6. Renormalization group - Wikipedia

    en.wikipedia.org/wiki/Renormalization_group

    The renormalization group is intimately related to scale invariance and conformal invariance, symmetries in which a system appears the same at all scales (self-similarity), [a] where under the fixed point of the renormalization group flow the field theory is conformally invariant. As the scale varies, it is as if one is decreasing (as RG is a ...

  7. Beta function (physics) - Wikipedia

    en.wikipedia.org/wiki/Beta_function_(physics)

    If the beta functions of a quantum field theory vanish, usually at particular values of the coupling parameters, then the theory is said to be scale-invariant. Almost all scale-invariant QFTs are also conformally invariant. The study of such theories is conformal field theory. The coupling parameters of a quantum field theory can run even if ...

  8. Jeffreys prior - Wikipedia

    en.wikipedia.org/wiki/Jeffreys_prior

    It is the unique (up to a multiple) prior (on the positive reals) that is scale-invariant (the Haar measure with respect to multiplication of positive reals), corresponding to the standard deviation being a measure of scale and scale-invariance corresponding to no information about

  9. Invariant (mathematics) - Wikipedia

    en.wikipedia.org/wiki/Invariant_(mathematics)

    This one is invariant under horizontal and vertical translation, as well as rotation by 180° (but not under reflection). In mathematics, an invariant is a property of a mathematical object (or a class of mathematical objects) which remains unchanged after operations or transformations of a certain type are applied to the objects.