# 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: 76 Search : function
 exponential function   کریای ِ نمایی   karyâ-ye nemâyiFr.: fonction exponentielle   A function in the form of y = bx defined for every → real number x, with positive base b > 1.→ exponential; → function. function   کریا   karyâFr.: fonction   A mathematical rule between two sets which assigns to each element of the first exactly one element of the second, as the expression y = axb.From M.Fr. fonction, from O.Fr. function, from L. functio (gen. functionis) "performance, execution," from functus, p.p. of fungor "to perform, execute."Karyâ, from Av. kairya- "function;" cf. Mod.Pers. Laki karyâ "done," Awromâni kiriyây, kiria "to be done," from kar- "to do" (Mod.Pers. kar-, kardan "to do, to make;" Mid.Pers. kardan; O.Pers./Av. kar- "to do, make, build;" Av. kərənaoiti "he makes;" cf. Skt. kr- "to do, to make," krnoti "he makes, he does," karoti "he makes, he does," karma "act, deed;" PIE base kwer- "to do, to make") + -ya suffix of verbal adjectives and nouns (e.g. išya- "desirable," jivya- "living, fresh," haiθya- "true," maidya- "middle," dadya- "grain"); cf. Skt. kāryá- "work, duty, performance." functional   ۱) کریایی؛ ۲) کریال   1) karyâyi; 2) karyâlFr.: 1) fonctionnel; 2) fonctionnelle   1) Math.: Of, relating to, or affecting a function. 2) A → function that associates a → real number or → complex number to a function or a → set of functions. A functional can be considered as a function of a set of several infinite and continuous → variables.→ function; → -al. Gaussian function   کریای ِ گاؤس   karyâ-ye GaussFr.: fonction de Gauss   The function e-x2, whose integral in the interval -∞ to +∞ gives the → square root of the → number pi: ∫e-x2dx = √π. It is the function that describes the → normal distribution.→ Gaussian; → function. Gibbs function   کریای ِ گیبس   karyâ-ye GibbsFr.: fonction de Gibbs   Same as → Gibbs free energy.Named after Josiah Willard Gibbs (1839-1903), an American physicist who played an important part in the foundation of analytical thermodynamics; → function. Hamiltonian function   کریای ِ هامیلتون   karyâ-ye HâmiltonFr.: fonction de Hamilton   A function that describes the motion of a → dynamical system in terms of the → Lagrangian function, → generalized coordinates, → generalized momenta, and time. For a → holonomic system having n degrees of freedom, the Hamiltonian function is of the form: H = Σpiq.i - L(qi,q.i,t) (summed from i = 1 to n), where L is the Lagrangian function. If L does not depend explicitly on time, the system is said to be → conservative and H is the total energy of the system. The Hamiltonian function plays a major role in the study of mechanical systems. Also called → Hamiltonian.Introduced in 1835 by the Irish mathematician and physicist William Rowan Hamilton (1805-1865); → function. hyperbolic function   کریایِ هذلولی   karyâ-ye hozluliFr.: fonction hyperbolique   Any of the six functions sinh, cosh, tanh, coth, csch, and sech that are related to the → hyperbola in the same way the → trigonometric functions relate to the → circle. Many of the formulae satisfied by the hyperbolic functions are similar to corresponding formulae for the trigonometric functions, except for + and - signs. For example: cosh2x - sinh2x = 1. See also: → hyperbolic cosine, → hyperbolic sine. Hyperbolic functions were first introduced by the Swiss mathematician Johann Heinrich Lambert (1728-1777).→ hyperbolic; → function. identity function   کریای ِ ایدانی   karyâ-ye idâniFr.: fonction d'identité   Math.: Any function f for which f(x) = x for all x in the domain of definition.→ identity; → function. implicit function   کریای ِ درتاهی   karyâ-ye dartâhiFr.: fonction implicite   A function which contains two or more variables that are not independent of each other. An implicit function of x and y is one of the form f(x,y) = 0, e.g., 4x + y2 - 9 = 0. See also → explicit function.→ implicit; → function. initial mass function (IMF)   کریا‌ی ِ آغازین ِ جرم   karyâ-ye âqâzin-e jermFr.: fonction initiale de masse   A mathematical expression describing the relative number of stars found in different ranges of mass for a cluster of stars at the time of its formation. It is defined as φ(log M) = dN / dlog M ∝ M -Γ, where M is the mass of a star and N is the number of stars in a logarithmic mass interval. The value of the slope found by Salpeter (1955) for → low-mass and → intermediate-mass stars in the → solar neighborhood is Γ = 1.35. The IMF can be expressed also in linear mass units: χ(M) = dN / DM ∝ M -α. Note that χ(M) = (1 / M lm 10) φ(log M), and α = Γ + 1. In this formalism the Salpeter slope is α = 2.35. There is a third way for representing the IMF, in which the exponent is x = -α. The IMF is not a single power law over all masses, from → brown dwarfs to → very massive stars (Kroupa, 2002, Science 295, 82). Different slopes have been found for different mass segments, as follows: α = 1.3 for 0.08 ≤ Msolar < 0.5; α = 2.3 for 0.5 ≤ Msolar < 1; α = 2.3 for 1 ≤ Msolar. The IMF at low masses can be fitted by a → lognormal distribution (See Bastian et al., 2010, ARAA 48, 339 and references therein). See also → canonical IMF.→ initial; → mass; → function. instrumental response function   کریای ِ پاسخ ِ سازال   karyâ-ye pâsox-e sâzâlFr.: fonction de la réponse instrumentale   The mathematical form of the way an instrument affects the input signal.→ instrumental; → response; → function. integral function   کریای ِ دُرُستالی   karyâ-ye dorostâliFr.: fonction intégrale   A function whose image is a subset of the integers, i.e. that takes only integer values.→ integral; → function. Lagrangian function   کریای ِ لاگرانژ   karyâ-ye lâgrânž (#)Fr.: Lagrangien, fonction de Lagrange   A physical quantity (denoted L), defined as the difference between the → kinetic energy (T) and the → potential energy (V) of a system: L = T - V. It is a function of → generalized coordinates, → generalized velocities, and time. Same as → Lagrangian, → kinetic potential.→ Lagrangian; → function. likelihood function   کریای ِ شدواری   karyâ-ye šodvâriFr.: fonction de vraisemblance   A function that allows one to estimate unknown parameters based on known outcomes. Opposed to → probability, which allows one to predict unknown outcomes based on known parameters. More specifically, a probability refers to the occurrence of future events, while a likelihood refers to past events with known outcomes.→ likelihood; → function. linear function   کریای ِ خطی   karyâ-ye xattiFr.: fonction linéaire   A function expressed by a → first degree equation that can be graphically represented in the → Cartesian coordinate plane by a → straight line.→ linear; → function. luminosity function   کریا‌ی ِ تابندگی   karyâ-ye tâbandegiFr.: fonction de luminosité   Number → distribution of → stars or galaxies (→ galaxy) with respect to their → absolute magnitudes. The luminosity function shows the → number of stars of a given intrinsic luminosity (or the number of galaxies per integrated magnitude band) in a given → volume of space.→ luminosity; → function. mass function   کریای ِ جرم   karyâ-ye jermFr.: fonction de masse   1) The number of a class of objects as a function of their mass. → initial mass function (IMF); → present-day mass function (PDMF). 2) A numerical relation between the masses of the two components of a → spectroscopic binary that provides information on the relative masses of the two stars when the spectral lines of only one component can be seen. If Mp is the mass of primary (whose spectrum is known), Ms is the mass of secondary, and i the → angle of inclination of the orbit, the mass function is given by: (Ms3. sin3i) / (Mp + Ms)2.→ mass; → function. membership function   کریای ِ هموندی   karyâ-ye hamvandiFr.: fonction d'adhésion   One of several functions used in the → fuzzification and → defuzzification steps of a → fuzzy logic system to map the → nonfuzzy input values to → fuzzy linguistic terms and vice versa. A membership function is used to quantify a linguistic term.→ membership; → function. metallicity distribution function (MDF)   کریای ِ واباژش ِ فلزیگی   karyâ-ye vâbâžeš-e felezigiFr.: fonction de distribution de métallicité   A plot representing the number of stars (or systems) per metallicity interval, usually expressed in [Fe/H] (abundance of → iron relative to → hydrogen).→ metallicity; → distribution; → function. modulation transfer function (MTF)   کریای ِ تراوژ ِ دگر‌آهنگش   karyâ-ye tarâvaž-e degarâhangešFr.: fonction de transfert de modulation   A measure of the ability of an optical system to reproduce (transfer) various levels of detail from the object to the image, as shown by the degree of contrast (modulation) in the image. → optical transfer function.→ modulation; → transfer; → function.