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An Abel function A(z) is a function associated with a function f (z) that satisfies the Abel functional equation. | ||
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The Abel functional equation is an equation which the Abel function
A(z) must satisfy:
A( f (z)) = A(z) + 1 |
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A special case of continuous meaning infinitely differentiable, plus some other requirements. The other requirements for a function being analytic differ depending on whether the requirements are for real analytic or complex analytic functions. | ||
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A Bell matrix B[ f ] is a matrix associated with a function f (x) such that:
B[ f (g)] = B[g] B[ f ], for some other function g(x). |
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A Carleman matrix M[ f ] is a matrix associated with a function f (x) such that:
M[ f (g)] = M[ f ] M[g], for some other function g(x). |
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Continuous things are usually contrasted with discrete things.
A good example of something continuous is the set of real numbers. |
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Continuous iteration is a generalization
of discrete iteration.
This effectively turns a function f (x) into a function g(n, x) = f n(x). Two ways of doing this are to satisfy: g(n, x) = f n(x) for integer n which is a weaker form of continuous iteration, or: g(1, x) = f (x) and g(y, x) = f (g(y − 1, x)) for all real y, and g(y, x) = g(y − 1, f (x)) for all real y which is a stronger form of continuous iteration. |
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Continuously iterated exponentiation can be interpreted as either:
a continuously iterated exponential function or a continuously iterated power function, but usually the former is implied, so on this website the former less ambiguous terminology will be used. |
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Discrete things are usually contrasted with continuous things.
A good example of something discrete is the set of integers. |
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See iteration | ||
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An exponential function is any function of the form:
expb(z) = bz |
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Exponentiation is the process of raising a base to a power.
Exponentiation is usually denoted: a^b or ab. |
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The n-th member of the hyper-operation sequence is known as hyper-n. | ||
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A hyper-operator is any member of the hyper-operator sequence. | ||
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The hyper-operator sequence is:
hyper1 = addition, hyper2 = multiplication, hyper3 = exponentiation, hyper4 = tetration, hyper5 = pentation ... and so on. |
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A hyperpower function is any function of the form:
hprn(z) = Tnz |
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The infinitely iterated exponential is T∞x. | ||
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An inverse function is a function g(x) associated with a
function f (x) that satisfies:
f (g(x)) = x and g( f (x)) = x over some interval of x. An inverse function is usually denoted: f −1(x). |
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An iterated exponential is a function of the form:
exp
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An iterated power is a function of the form:
pownb(z) for integer n. |
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The t-fold iterate of a function f (x) is f t(x) where t is constant. | ||
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An iterate family is a family of iterates f t(x) indexed by t. | ||
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Iteration is the process of applying a function repeatedly, or using the output of a function as its input, a given number of times. | ||
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The Lambert W-function is the inverse function of:
f (x) = xex |
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A logarithm is an inverse function of an exponential function | ||
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A matrix is a 2-dimensional array of elements.
The elements of a matrix are usually integers or real numbers. |
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A number associated with "how big" a number is.
The elements of a matrix are usually integers or real numbers. |
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The orbit of a function f (x) from x is f t(x) where x is constant. | ||
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An orbit family is a family of orbits f t(x) indexed by x. | ||
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Pentation is the orbit of a tetrational function from 1. | ||
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A power function is any function of the form:
pown(z) = zn |
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A product-logarithm is the inverse function of:
f (x) = xbx |
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A root is an inverse function of a power function. | ||
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A root is also another name for a zero of a function. | ||
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An Schroeder function S(z) is a function associated with a function f (z) that satisfies the Schroeder functional equation. | ||
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The Schroeder functional equation is an equation
which the Schroeder function
S(z) must satisfy:
S( f (z)) = c S(z) |
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Old name for tetration | ||
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A super-logarithm is an inverse function of a tetrational function. | ||
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A super-root is an inverse function of a hyperpower function | ||
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Tetration is the orbit of an exponential function from 1. Tetration is usually denoted: x^^y or yx, but here it is denoted Tyx for clarity, consistency, and usability reasons. For more information on tetration, two really great places to start are: MathWorld and Wikipedia, and the page on this site: Tetration | ||
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A tetrational function is any function of the form:
tetb(z) = zb |
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A zero of a function is a number c such that f (c) = 0 | ||