Find the smallest σ-algebra on Ω generated by
C , if
(i) Ω = R and C=( −20, √2), (−15, ∞)
,
(ii) Ω = R and C=(1, 2], {2})
,
(iii) Ω = {1, 2, 3, 4} and C={{∅},2, 3}}
,
(iv) Ω = {1, 2, 3, 4} and {3 }, {2, 3, 4} .
You could have found this, Sigma Algebras, as easily as I did.