1
$\begingroup$

Give an example of sigma algebra in $\mathcal P(\Bbb N)$ whose order is finite, and also whose order is infinite, and whose order is $10$?

(the order means the number of elements)

  • 0
    What is the order of a $\sigma$-algebra? If it is the number of elements, there is no $\sigma$-algebra with exactly $10$ elements.2012-10-20
  • 0
    why is that?and yes the order is the number of element2012-10-20
  • 1
    Well, well. What a lazy question. Nonetheless plus one because I learned something from reading Davide's answer.2012-10-20
  • 2
    Welcome to math.SE: since you are new, I wanted to let you know a few things about the site. In order to get the best possible answers, it is helpful if you say in what context you encountered the problem, and what your thoughts on it are; this will prevent people from telling you things you already know, and help them give their answers at the right level. Also, many find the use of imperative ("Prove", "Solve", etc.) to be rude when asking for help; please consider rewriting your post.2012-10-21

1 Answers 1