analogical ânâguyik Fr.: analogique Of, relating to, or based on analogy; expressing or implying analogy. |
anisotropic homogeneous cosmological model model-e keyhânšenâxti-ye hamgen o nâ-izogard Fr.: modèle cosmiologique homogène mais anisotrope A solution to Einstein's theory of → general relativity that is spatially homogeneous but allows for rotation and/or shear. See also → Bianchi cosmological model. → anisotropic; → homogeneous; → cosmological; → model. |
asteroseismologic axtarlarzešenâsi, axtarlarzešenâsik Fr.: astérosismologique Of or relating to → asteroseismology. → spectropolarimetry; → -ic. |
Bianchi cosmological model model-e keyhânšenâxti-ye Bianchi Fr.: modèle cosmologique de Bianchi A cosmological model based on the theory of → general relativity, which is homogeneous but → anisotropic. There are actually ten dinstinct Bianchi types, classified according to the particular kinds of symmetry they posses. Luigi Bianchi (1856-1928), Italian mathematician; → cosmological; → model. |
bivalent logic guyik-e do-arz Fr.: logique bivalente A logical system, such as → classical logic, in which every declarative sentence expressing a → proposition has exactly one → truth value, either → true or → false. Bivalent logic is just a sub-set of a more powerful type of logic known as → fuzzy logic. See also → polyvalent logic. |
classical logic guyik-e kelâsik Fr.: logique classique The traditional logic in which → sets are sharply defined (→ crisp set) for example, the number of students registered for a course, or the names beginning with P in a given telephone directory. Classical logic also defines relations between sets of → propositions. Consider for example two sets: elephants and mammals, a simple proposition would be the assertion that all elephants are mammals, that is E ⊂ M, where E is the elephant set and M is the mammal set. The classical logic proposition is either true or false. Compare with → fuzzy logic. |
cosmological keyhânšenâxti, keyhânšenâsik Fr.: cosmologique Pertaining or relating to → cosmology. |
cosmological constant pâyâ-ye keyhânšenâsik, ~ keyhânšenâxti Fr.: constante cosmologique A term introduced by Einstein into his gravitational → field equations in order to allow a solution corresponding to a → static Universe. The cosmological constant is physically interpreted as due to the → vacuum energy of quantized fields. See also → dark energy. → cosmological; → constant. |
cosmological constant problem parâse-ye pâyâ-ye keyhânšenâxti Fr.: problème de la constante cosmologique The impressive discrepancy of about 120 orders of magnitude between the theoretical value of the → cosmological constant and its observed value. → Quantum field theory interprets the cosmological constant as the density of the → vacuum energy. This density can be derived from the maximum energy at which the theory is valid, i.e. the → Planck energy scale (10^{18} GeV). The theoretical vacuum → energy density is (10^{18} GeV)^{4} = (10^{27} eV)^{4} = 10^{112} erg cm^{-3}. On the other hand, the observed vacuum energy density is estimated to be about (10^{-3} eV)^{4} = 10^{-8} erg cm^{-3}. There is, therefore, a discrepancy of about 120 orders of magnitude. → cosmological; → constant; → problem. |
cosmological distance durâ-ye keyhânšenâsik, ~ keyhânšenâxti Fr.: distance cosmologique The distance to a remote galaxy based on its redshift assuming that the redshift is caused by the → Doppler effect and reflects the general expansion of the Universe. → cosmological; → distance . |
cosmological epoch zime-ye keyhânšenâxti Fr.: époque cosmologique → cosmological; → epoch. |
cosmological model model-e keyhânšenâsik, ~ keyhânšenâxti Fr.: modèle cosmologique A mathematical description of the Universe, based on observation, which tries to explain its current aspect, and to describe its evolution during time. → cosmological; → model. |
cosmological principle parvaz-e keyhânšenâsik, ~ keyhânšenâxti Fr.: principe cosmologique The → hypothesis that on → large scales the → Universe is → isotropic and → homogeneous, that is, it appears the same at all places and, from any one place, looks the same in all directions. See also → perfect cosmological principle. |
cosmological redshift sorxkib-e keyhânšenâsik, ~ keyhânšenâxti Fr.: décalage vers le rouge cosmologique, redshift ~ The → redshift of a remote object (galaxy, quasar, supenova) due to the expansion of the Universe. → cosmological; → redshift. |
current cosmological epoch zime-ye keyhânšenâxti-ye konuni Fr.: époque cosmologique actuelle The → Universe at the → redshift z = 0. → current; → cosmological; → epoch. |
first-order logic (FOL) guyik-e farâsani-ye râye-ye naxost, ~ farâsanhâ-ye ~ ~ Fr.: logique des prédicats du premier ordre A system of → formal logic that is an extension of → propositional logic. It is also known as → first-order predicate calculus and → predicate logic. FOL eliminates deficiencies of propositional logic by: representing → objects (their properties, relations and statements about them), introducing → variables, and introducing → quantifiers. |
formal logic guyik-e diseyi, ~ disevar Fr.: logique formelle The traditional or → classical logic in which the → validity or → invalidity of a conclusion is deduced from two or more statements (→ premises). Based on Aristotle's (384-322 BC) theory of → syllogism, systematized in his book "Organon," its focus is not on what is stated (the content) but on the structure (form) of the → argument and the validity of the inference drawn from the premises of the argument; if the premises are true then the logical consequence must also be true. Formal logic is → bivalent, that is it recognizes only two → truth values: → true and → false. The basic principles of formal logic are: 1) → principle of identity, 2) → principle of excluded middle, and 3) → principle of non-contradiction. See also → symbolic logic, → fuzzy logic. |
fuzzy logic guyik-e porzvâr Fr.: logic flou A mathematical logic that recognizes more than simple → true and → false → propositions. With fuzzy logic, propositions can be represented with degrees of truthfulness and falsehood. In this system, → truth values are → fuzzy sets without sharp boundaries (→ crisp set) in contrast with → classical logic. Fuzzy logic is applied to a wide range of problems including: industrial control, domestic goods, decision making, robotics, intelligent machines, and image processing in medicine. |
fuzzy logic system râžmân-e guyik-e porzvâr Fr.: système de logic flou An engineering system which uses → fuzzy logic. It generally consists of four main components: → fuzzification interface (fuzzifier), → fuzzy rule base, → fuzzy inferencing unit, and → defuzzification interface (difuzzifier). Also called → fuzzy inference system. |
geologic zaminšenâxti (#) Fr.: géologique Of, pertaining to, or based on → geology. Also geological. |