Timeline for How to calculate number of sets in Sigma Algebra
Current License: CC BY-SA 4.0
9 events
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| Nov 18, 2019 at 18:00 | history | tweeted | twitter.com/StackStats/status/1196488370924539906 | ||
| Nov 18, 2019 at 17:27 | comment | added | whuber♦ | In set theory, the cardinal number $2^n$ is defined to be the cardinality of the set of functions from a set of $n$ elements to a set of $2$ elements. Writing the latter set as $\{0,1\}$ (with no loss of generality) shows these functions can be identified with the indicator functions on $\mathcal B$--but an indicator function is determined by, and determines, the subset of $\mathcal B$ on which it equals $1,$ QED. In this way the quoted statement makes sense even when $\mathcal B$ is countably infinite. | |
| Nov 18, 2019 at 16:12 | answer | added | BCLC | timeline score: 3 | |
| Nov 18, 2019 at 12:47 | history | became hot network question | |||
| Nov 18, 2019 at 8:21 | answer | added | knrumsey | timeline score: 9 | |
| Nov 18, 2019 at 6:15 | vote | accept | Nemo | ||
| Nov 18, 2019 at 5:38 | history | edited | gunes |
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| Nov 18, 2019 at 5:37 | answer | added | gunes | timeline score: 16 | |
| Nov 18, 2019 at 4:35 | history | asked | Nemo | CC BY-SA 4.0 |