Urur kooban

Xisaab ahaan, waxay ahaanaysaa urur uun urur kooban haddii laga helo xiriirka Midmid ku dhexjirta iyo Urur kale leh qaabka {1, 2, ..., n} kolka n waana Tiro tirsiimo. Tusaale ahaan, Ururta

$\{2,4,6,8,10\}\,\!$

waana urur kooban tirada shanta qaybood. Waxaa loo ogolyahay qiime ahaan in ay ka koobnaato n = 0 Sidaa darteed maxaa yeelaay urur madhan waana ururu kooban.

Qeexista eryaga loo adeegsado

Waxaa la yiraah Urur kastoo S, waa koobantahay haddii la helo Midmid

$f\colon S\rightarrow \{1,\ldots ,n\}$

marka n Tiro tirsiimo Ogaal guud. Haddii urur uun kooban, waxaa loo qarayaa susun sidaan:

$S=\{x_{1},x_{2},\ldots ,x_{n}\}.$

eeg sidoo kale

• Tiro susun

Tixraac

• Patrick Suppes, Axiomatic Set Theory, D. Van Nostrand Company, Inc., 1960