Qhov kev faib ua feem yuav yog dab tsi?

2024 Tus sau: Miles Stephen | [email protected]. Kawg hloov kho: 2023-12-15 23:36

Muab faib : Ib pawg ntawm cov teeb B1, B2,, Bn tau hais rau muab faib qhov chaw qauv yog tias cov teeb tsa (i) sib koom ua ke thiab (ii) muaj kev sib koom ua ke tag nrho cov qauv qhov chaw. Ib qho piv txwv yooj yim ntawm a muab faib yog muab los ntawm ib txheej B, ua ke nrog nws ntxiv B. 2.

Tsis tas li lo lus nug yog, dab tsi yog kev faib tawm hauv kev txheeb cais?

A muab faib ntawm ib txheej X yog ib pawg ntawm cov tsis-nplua subsets ntawm X xws li tias txhua lub caij x hauv X yog nyob rau hauv ib qho ntawm cov subsets (piv txwv li, X yog ib qho kev sib koom ua ke ntawm cov subsets).

Tsis tas li ntawd, koj ua li cas thiaj nrhiav tau tag nrho qhov tshwm sim? Cov qhov tshwm sim rau ib qho tuaj yeem sau ua cov lej ntawm qhov xwm txheej B. Lub tag nrho qhov tshwm sim txoj cai yog: P(A) = P(A∩B) + P(A∩B^c). Nco tseg: ∩ txhais tau tias "kev sib tshuam" thiab B^c yog qhov ntxiv ntawm B.

Kuj paub yog, qhov muab faib txhais li cas hauv lej?

Kev faib tawm yog ib txoj hauv kev ua haujlwm lej teeb meem uas koom nrog coob tus los ntawm kev faib lawv mus rau hauv me me kom lawv yooj yim dua rau kev ua hauj lwm nrog. Yog li, tsis txhob ntxiv cov lej hauv kab, zoo li qhov no…

Koj puas paub ntau npaum li cas partitions ib lub teeb muaj?

Teeb partitions Feem ntau, B yog cov tus naj npawb ntawm partitions ntawm ib txheej ua size n. A muab faib ntawm ib txheej S yog txhais ua a teeb ntawm nonnempty, pairwise disjoint subsets ntawm S uas nws union yog S. Piv txwv li, B₃ = 5 vim 3 teeb {a, b, c} tau muab faib hauv 5 txoj kev sib txawv: { {a}, {b}, {c} } {a}, {b, c} }