# An Etymological Dictionary of Astronomy and AstrophysicsEnglish-French-Persian

## فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

### M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 23 Search : tensor
 absolute tensor   تانسور ِ اوست   tânsor-e avastFr.: tenseur absolu   A → tensor of → weight  → zero.→ absolute; → tensor. calculus of tensors   افماریک ِ تانسورها   afmârik-e tânsorhâFr.: calcul tensoriel   The branch of mathematics dealing with the differentiation of tensors.→ calculus; → tensor.Afmârik, → calculus; → tensor. contravariant tensor   تانسور ِ پادورتا   tânsor-e pâdvartâFr.: tenseur contravariant   A tensor whose components are distinguished by → superscript indices.→ contra-; + variant; → variance; → tensor. covariant tensor   تانسر ِ هم‌ورتا   tânsor-e hamvartâFr.: tenseur covariant   A tensor whose components are distinguished by → subscript indices.→ covariant; → tensor. Einstein tensor   تانسور ِ اینشتین   tânsor-e Einstein (#)Fr.: tenseur d'Einstein   A mathematical entity describing the → curvature of → space-time in → Einstein's field equations, according to the theory of → general relativity. It is expressed by Gμν = Rμν - (1/2) gμνR, where Rμν is the Ricci tensor, gμν is the → metric tensor, and R the scalar curvature. This tensor is both symmetric and divergence free.Named after Albert Einstein (1879-1955); → tensor. energy-momentum tensor   تانسور ِ کاروژ-جنباک   tânsor-e kâruž-jonbâkFr.: tenseur énergie-quantité de mouvement   A tensor (Tμν) related to the → Einstein tensor through → Einstein's field equations. The energy-momentum tensor depends upon the distribution of the → energy and → matter in the space.→ energy; → momentum; → tensor. metric tensor   تانسور ِ متریک   tânsor-e metrikFr.: tenseur métrique   The abstract tensor operation which is computed in a particular → reference frame using the → metric components. The metric tensor defines magnitude and direction of vectors about a point.→ metric; → tensor. order of a tensor   رایه‌ی ِ تانسور   râye-ye tânsorFr.: ordre de tenseur   The maximum number of the indices (→ index) of a tensor.→ order; → tensor. relative tensor   تانسور ِ بازانی   tânsor-e bâzâniFr.: tenseur relatif   A generalized tensor concept that is characterized by a → Jacobian matrix of transformation raised to a power called → weight of a tensor density. In practice, only relative tensors of weight 1 or -1 are used. The product of a relative tensor of weight -1 by another tensor of weight 1 is an → absolute tensor. Same as → tensor density.→ relative; → tensor. Ricci tensor   تانسور ِ ریتچی   tânsor-e RicciFr.: tenseur de Ricci   A → rank 2, → symmetric tensor Rμν that is a contraction of the → Riemann curvature tensor Rλμνλ. More specifically, Rμν ≡ Σ (λ) Rλμνκ = Rλμνκ. Closely related to the Ricci tensor is the → Einstein tensor, which plays an important role in the theory of → general relativity.Named after the Italian mathematician Gregorio Ricci-Curbastro (1853-1925); → tensor. Riemann curvature tensor   تانسور ِ خمیدگی ِ ریمان   tânsor-e xamidegi-ye RiemannFr.: tenseur de courbure de Riemann   A 4th → rank tensor that characterizes the deviation of the geometry of space from the Euclidean type. The curvature tensor Rλμνκ is defined through the → Christoffel symbols Γλμν as follows: Rλμνκ = (∂Γλμκ)/(∂xν) - (∂Γλμν)/(∂xκ) + ΓημκΓλην - ΓημνΓληκ.→ Riemannian geometry; → curvature; → tensor. scalar-tensor theory   نگره‌ی ِ مرپلی-تانسوری   negare-ye marpel-tânsoriFr.: théorie scalaire-tensorielle   An alternative to the standard → general relativity of gravity that contains not only the → tensor field (or → metric), but also a → scalar field. In this formalism, the → gravitational constant is considered to vary over time. As a consequence, the measured strength of the gravitational interaction is a function of time. Same as → Jordan-Brans-Dicke theory.→ scalar; → tensor; → theory. skew-symmetric tensor   تانسور ِ پاد-همامون   tânsor-e pâdhamâmunFr.: tenseur antisymétrique   A tensor that is the negative of its → transpose. For example, a second-order covariant tensor Ajk if its components satisfy the equality: Ajk = - Akj. Also called antisymmetric tensor.→ skew; → symmetric; → tensor.Tânsor, → tensor; pâd-, → anti-; hamâmun, → symmetric. symmetric tensor   تانسور ِ همامون   tânsor-e hamâmunFr.: tenseur symétrique   A tensor that is → invariant under any → permutation of its indices (→ index). In other words, a tensor that equals its → transpose. For example, a second-order → covariant tensor Ajk if its components satisfy the equality: Ajk = Akj.→ symmetric; → tensor. tensor   تانسور، تانگر   tânsor, tângarFr.: tenseur   A system of numbers or functions where components obey a certain law of transformation when the variables undergo a linear transformation. A tensor may consist of a single number, in which case it is referred to as a tensor of order zero, or simply a → scalar. The tensor of order one represents a → vector. Similarly there will be tensors of order two, three, and so on. See also: → absolute tensor, → calculus of tensors, → contravariant tensor, → covariant tensor, → Einstein tensor, → energy-momentum tensor, → metric tensor, → order of a tensor, → relative tensor, → Ricci tensor, → Riemann curvature tensor, → scalar-tensor theory, → skew-symmetric tensor, → symmetric tensor, → tensor analysis, → tensor contraction, → tensor density, → tensor field, → tensor perturbation, → tensor rank, → tensor-vector-scalar (TeVeS) theory, → weight of a tensor.Agent noun of tense (v.) → tension. tensor analysis   آ نالس ِ تانسوری، ~ ِ تانگری   ânâlas-e tânsoriFr.: analyse tensorielle   A method of calculation in higher mathematics based on the properties of tensors.→ tensor; → analysis. tensor contraction   ترنگش ِ تانسور   terengeš-e tânsorFr.: contraction de tenseur   An operation of tensor algebra that is obtained by setting unlike indices equal and summing according to a summation convention.→ contraction; → tensor. tensor density   چگالی ِ تانسور   cagâli-ye tânsorFr.: densité de tenseur   A generalization of the tensor concept that like a tensor transforms, except for the appearance of an extra factor, which is the → Jacobian matrix of the transformation of the coordinates, raised to some power, in transformation law. The exponent, which is a positive or negative integer, is called the weight of the tensor density. → weight of a tensor density. Ordinary tensors are tensor densities of weight 0. Tensor density is also called → relative tensor.→ tensor; → density. tensor field   میدان ِ تانسوری   meydân-e tânsoriFr.: champ tensoriel   A field of space and time each point of which has multiple directionality, and is describable by a tensor function.→ tensor; → field. tensor perturbation   پرتورش ِ تانسوری   partureš-e tânsoriFr.: perturbation tensorielle   The perturbation in the → primordial Universe plasma caused by → gravitational waves. These waves stretch and squeeze space in orthogonal directions and bring about → quadrupole anisotropy in incoming radiation temperature.→ tensor; → perturbation.

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