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  2. Positive operator - Wikipedia

    en.wikipedia.org/wiki/Positive_operator

    The operator is said to be positive-definite, and written >, if , >, for all ⁡ {}. [ 1 ] Many authors define a positive operator A {\displaystyle A} to be a self-adjoint (or at least symmetric) non-negative operator.

  3. Positive-definite function - Wikipedia

    en.wikipedia.org/wiki/Positive-definite_function

    Positive-definiteness arises naturally in the theory of the Fourier transform; it can be seen directly that to be positive-definite it is sufficient for f to be the Fourier transform of a function g on the real line with g(y) ≥ 0.

  4. Normal operator - Wikipedia

    en.wikipedia.org/wiki/Normal_operator

    Normal operators are important because the spectral theorem holds for them. The class of normal operators is well understood. Examples of normal operators are unitary operators: N* = N −1; Hermitian operators (i.e., self-adjoint operators): N* = N; skew-Hermitian operators: N* = −N; positive operators: N = MM* for some M (so N is self-adjoint).

  5. List of Unicode characters - Wikipedia

    en.wikipedia.org/wiki/List_of_Unicode_characters

    95 characters; the 52 alphabet characters belong to the Latin script. The remaining 43 belong to the common script. The 33 characters classified as ASCII Punctuation & Symbols are also sometimes referred to as ASCII special characters. Often only these characters (and not other Unicode punctuation) are what is meant when an organization says a ...

  6. List of things named after Charles Hermite - Wikipedia

    en.wikipedia.org/wiki/List_of_things_named_after...

    Hermitian form, a specific sesquilinear form; Hermitian function, a complex function whose complex conjugate is equal to the original function with the variable changed in sign; Hermitian manifold/structure Hermitian metric, is a smoothly varying positive-definite Hermitian form on each fiber of a complex vector bundle

  7. Glossary of mathematical symbols - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_mathematical...

    2. Double factorial: if n is a positive integer, n!! is the product of all positive integers up to n with the same parity as n, and is read as "the double factorial of n". 3. Subfactorial: if n is a positive integer, !n is the number of derangements of a set of n elements, and is read as "the subfactorial of n". *

  8. Operator (physics) - Wikipedia

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

    The operators must yield real eigenvalues, since they are values which may come up as the result of the experiment. Mathematically this means the operators must be Hermitian. [1] The probability of each eigenvalue is related to the projection of the physical state on the subspace related to that eigenvalue.

  9. Definite matrix - Wikipedia

    en.wikipedia.org/wiki/Definite_matrix

    In mathematics, a symmetric matrix with real entries is positive-definite if the real number is positive for every nonzero real column vector, where is the row vector transpose of . [1] More generally, a Hermitian matrix (that is, a complex matrix equal to its conjugate transpose) is positive-definite if the real number is positive for every nonzero complex column vector , where denotes the ...