| 释义 |
surjection
sur·jec·tion S0916850 (sər-jĕk′shən)n. Mathematics A function that is onto.
[sur- + (pro)jection.]surjection (sɜːˈdʒɛkʃən) n (Mathematics) a mathematical function or mapping for which every element of the image space is a value for some members of the domain. See also injection5, bijection[C20: from sur-1 + -jection, on the model of projection] surˈjective adjTranslationssurjection
surjection[sər′jek·shən] (mathematics) A mapping ƒ from a set A to a set B such that for every element b of B there is an element a of A such that ƒ (a) = b. Also known as surjective mapping. surjection (mathematics)A function f : A -> B is surjective or onto or asurjection if f A = B. I.e. f can return any value in B.This means that its image is its codomain.
Only surjections have right inverses, f' : B -> A wheref (f' x) = x since if f were not a surjection there would beelements of B for which f' was not defined.
See also bijection, injection. |