Diagonalization (other)
In logic and mathematics, diagonalization may refer to: * Matrix diagonalization, a construction of a diagonal matrix (with nonzero entries only on the main diagonal) that is similar to a given matrix * Diagonal argument (other), various closely related proof techniques, including: ** Cantor's diagonal argument, used to prove that the set of real numbers is not countable **Diagonal lemma, used to create self-referential sentences in formal logic * Table diagonalization, a form of data reduction Data reduction is the transformation of numerical or alphabetical digital information derived empirically or experimental data, experimentally into a corrected, ordered, and simplified form. The purpose of data reduction can be two-fold: reduce the ...

Matrix Diagonalization
In linear algebra, a square matrix A is called diagonalizable or non-defective if it is similar to a diagonal matrix, i.e., if there exists an invertible matrix P and a diagonal matrix D such that or equivalently (Such D are not unique.) For a finite-dimensional vector space a linear map T:V\to V is called diagonalizable if there exists an ordered basis of V consisting of eigenvectors of T. These definitions are equivalent: if T has a matrix representation T = PDP^ as above, then the column vectors of P form a basis consisting of eigenvectors of and the diagonal entries of D are the corresponding eigenvalues of with respect to this eigenvector basis, A is represented by Diagonalization is the process of finding the above P and Diagonalizable matrices and maps are especially easy for computations, once their eigenvalues and eigenvectors are known. One can raise a diagonal matrix D to a power by simply raising the diagonal entries to that power, and the determina ...
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Diagonal Argument (other)
A diagonal argument, in mathematics, is a technique employed in the proofs of the following theorems: *Cantor's diagonal argument (the earliest) *Cantor's theorem *Russell's paradox *Diagonal lemma ** Gödel's first incompleteness theorem **Tarski's undefinability theorem *Halting problem *Kleene's recursion theorem See also * Diagonalization (other) In logic and mathematics, diagonalization may refer to: * Matrix diagonalization, a construction of a diagonal matrix (with nonzero entries only on the main diagonal) that is similar to a given matrix * Diagonal argument (other), various ...

Cantor's Diagonal Argument
In set theory, Cantor's diagonal argument, also called the diagonalisation argument, the diagonal slash argument, the anti-diagonal argument, the diagonal method, and Cantor's diagonalization proof, was published in 1891 by Georg Cantor as a mathematical proof that there are infinite sets which cannot be put into one-to-one correspondence with the infinite set of natural numbers. English translation: Such sets are now known as uncountable sets, and the size of infinite sets is now treated by the theory of cardinal numbers which Cantor began. The diagonal argument was not Cantor's first proof of the uncountability of the real numbers, which appeared in 1874. However, it demonstrates a general technique that has since been used in a wide range of proofs, including the first of Gödel's incompleteness theorems and Turing's answer to the ''Entscheidungsproblem''. Diagonalization arguments are often also the source of contradictions like Russell's paradox and Richard's paradox. ...
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Diagonal Lemma
In mathematical logic, the diagonal lemma (also known as diagonalization lemma, self-reference lemma or fixed point theorem) establishes the existence of self-referential sentences in certain formal theories of the natural numbers—specifically those theories that are strong enough to represent all computable functions. The sentences whose existence is secured by the diagonal lemma can then, in turn, be used to prove fundamental limitative results such as Gödel's incompleteness theorems and Tarski's undefinability theorem. Background Let \mathbb be the set of natural numbers. A first-order theory T in the language of arithmetic ''represents'' the computable function f: \mathbb\rightarrow\mathbb if there exists a "graph" predicate \mathcal_f(x, y) in the language of T such that for each n \in \mathbb : \vdash_\,(\forall y) ^\circ f(n)=y) \Leftrightarrow \mathcal_f(^\circ n,\,y)/math> Here ^\circ n is the numeral corresponding to the natural number n, which is defined to be ...
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Table Diagonalization
Diagonalization is the process of re-ordering the rows and columns of tables and charts so that the data forms an approximately diagonal line.Jacques Bertin, '' Semiology of Graphics: Diagrams, Networks, Maps''. ESRI Press, 2010, 168-169. This makes it easier for people to see patterns in the data. Diagonalization typically involves either raw data, percentages, mean There are several kinds of mean in mathematics, especially in statistics. Each mean serves to summarize a given group of data, often to better understand the overall value (magnitude and sign) of a given data set. For a data set, the ''arithme ...s or residuals. Generally once tables are diagonalized one of two patterns appears: hierarchy or segmentation References {{Reflist * Infographics ...
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