acronical setting فروشد ِ شامگاهی forušod-e šâmgâhi
*Fr.: coucher acronyque*
The setting of a star at nightfall. → *heliacal setting*. → *acronical*; → *setting*. |

affine set هنگرد ِ کروَن hangard-e karvan
*Fr.: ensemble affine*
A set → *if and only if (iff)*
for any two points in the → *set*,
the line through them is contained in the set. In other words, for any two points in
the set, their → *affine combination*s
are in the set itself. → *affine*; → *set*. |

alpha offset اپنه ِ آلفا apneh-e Âlfâ
*Fr.: offset en ascension droite*
A short distance from the target, in right ascension, where
the telescope is pointed for various purposes. → *alpha*; → *offset*. |

apparent setting فروشد ِ پدیدار forušod-e padidâr
*Fr.: coucher apparent*
The instant of time when the object is in the West and the geometric
→ *zenith distance* is equal to 90° plus the
→ *horizontal refraction* plus
the semidiameter minus the → *parallax*. → *apparent*; → *setting*. |

bias offset اپنه ِ ورک apneh-e varak
*Fr.: biais*
In → *CCD detector*s, same as
→ *bias* and → *offset*. → *bias*; → *offset*. |

complete set هنگرد ِ اسپر hangard-e ospor
*Fr.: ensemble complet*
*Quantum mechanics*: A set of states such that any state can be represented as a
superposition of them.
→ *complete*; → *set*. |

crisp set هنگرد ِ توج hangard-e tuj
*Fr.: ensemble net*
A classical set that allows only full membership or no membership at all for its elements, as
contrasted with a → *fuzzy set*.
Crisp set can be viewed as a restricted case of the more general fuzzy set concept. |

delta offset اپنه ِ دلتا apneh-e deltâ
*Fr.: offset en déclinaison*
A short distance from the target, in → *declination*,
where the → *telescope* is pointed for various purposes. → *delta*; → *offset*. |

disk settling نیاشش ِ گرده، ~ دیسک niyâšeš-e gerdé, ~ disk
*Fr.: stabilisation de disque*
The process whereby a → *galaxy*
evolves from a disturbed to an ordered system, as it
develops into a → *rotation*
dominated → *settled disk*. → *disk*; → *settling*. |

dust settling نیاشش ِ غبار niyâšeš-e qobâr
*Fr.: dépose de poussières*
A process occurring in → *protoplanetary disk*s whereby
relatively large → *dust grain*s settle to the disk midplane.
These grains, with sizes from → *micron* to
→ *millimeter*, grow from smaller dust grains
and will eventually give rise to a planetary system. → *dust*; → *settling*. |

empty set هنگرد ِ تهی hangard-e tohi
*Fr.: ensemble vide*
A set containing no → *element*s. → *empty*; → *set*. |

family of sets خانوادهی ِ هنگردها xânevâde-ye hangardhâ
*Fr.: famille de comètes*
A → *collection* of → *subset*s of a set. → *family*; → *set*. |

finite set هنگرد ِ کرانمند hangard-e karânmand
*Fr.: ensemble fini*
A → *set* whose elements can be numbered from 1 to *n*, for some
positive integer *n*. → * finite*; → *set*. |

fuzzy set هنگرد ِ پرزوار hangard-e porzvâr
*Fr.: ensemble flou*
A set of → *truth value*s in → *fuzzy logic*
that does not have sharp boundaries. Instead, set members have degrees of membership.
If the value of 1 is assigned to objects entirely within the set and a 0 is assigned
to objects outside of the set, then any object partially in the set will have a value
between 0 and 1. This contrast with → *crisp set*s
in → *classical logic*
where members assume a precise value of 1 or 0. Fuzzy sets were first introduced by
Lotfi A. Zadeh (1965) and defined as follows.
Let X be a space of points, with a generic element of X denoted by *x*. Thus X = {*x*}.
A fuzzy set A in X is characterized by a → *membership function*
*f*_{A}(*x*)
which associates with each point in X a real number in the interval [0,1], with the
values of *f*_{A}(*x*) at *x* representing the "grade of membership"
of *x* in A. Thus, the nearer the value of *f*_{A}(*x*)
to unity, the higher the grade of membership of *x* in A.
Generally, the intersection operations of fuzzy sets are the expansion of that
operation on → *nonfuzzy set*s. In other words, operations on
nonfuzzy sets are a particular case of operations on fuzzy sets. → *fuzzy*; → *set*. |

gravitational settling نیاشش ِ گرانشی niyâšeš-e gerâneši
*Fr.: décantation par gravité*
A physical process occurring in → *stellar atmosphere*s
whereby in a very stable atmosphere
→ *heavy element*s are gravitationally pulled down preferentially.
If such an atmosphere is stable for long periods of time, the
→ *absorption line*s of
heavy elements may therefore become very weak. Observationally, the star seems
to contain only → *hydrogen* and
→ *helium*.
Gravitational settling takes place in the Sun at
the bottom of the outer → *convective zone* where helium is
dragged down, leading to a surface He abundant smaller than the cosmic value. It occurs
also in the atmospheres of → *brown dwarf*s and
→ *planet*s. See also
→ *radiative levitation*,
→ *element diffusion*, → *thermal diffusion*. → *gravitational*; → *settling*. |

heliacal setting فروشد ِ هورانه forušod-e hurâné
*Fr.: coucher héliaque*
The last visible setting of a star below the western horizon just after sunset
entering into a conjunction with the Sun. → *heliacal*; → *setting*. |

infinite set هنگرد ِ بیکران hangard-e bikarân
*Fr.: ensemble infini*
A set which can be put in a one-to-one correspondence with part of itself. → *infinite*; → *set*. |

Mandelbrot set هنگرد ِ ماندلبروت hangard-e Mandelbrot
*Fr.: ensemble de Mandelbrot*
A set of points in the complex plane, the boundary of which forms a fractal
with varying shapes at different magnifications.
Mathematically, it is the set of all *C* values for which the iteration
*z*_{n+1} = z_{n}^{2} + C,
starting from *z*_{0} = 0, does not diverge to infinity. Discovered by Benoît Mandelbrot (1924-)
a Polish-born French mathematician, best known as the "father of fractal geometry;"
→ *set*. |

moonset فروشد ِ مانگ forušod-e mâng (#)
*Fr.: coucher de la lune*
The crossing of the visible horizon by the upper limb of the descending Moon. → *moon*; → *set*. |

moonset lag لک ِ فروشد ِ مانگ lek-e forušod-e mâng
*Fr.: retard du coucher de la lune*
The delay between → *sunset* and → *moonset*. → *moonset*; → *lag*. |