===== Smallest generated σ-algebra =====
==== Set ====
| @#55CCEE: context     | @#55CCEE: $X$ |

| @#55EE55: postulate   | @#55EE55: $\sigma(A):\equiv \bigcap \{C\ |\ A\subseteq C\land C\subseteq \mathrm{SigmaAlgebra}(X)\} $ |
==== Discussion ====
The smallest σ-algebra over $X$ generated by, and hence containing, $A$.
 
==== Reference ====
Wikipedia: [[http://de.wikipedia.org/wiki/%CE%A3-Algebra#Bedeutung|σ-Operator (german)]]
==== Parents ====
=== Element of ===
[[σ-algebra]]