A measure space $(X, \Sigma, \mu)$ is finite if $\mu(X)<\infty$.
It is equivalent to saying that $(X, \Sigma, \mu)$ is finite if $\mu(E)<\infty$ for all $E \in \Sigma$
A measure space $(X, \Sigma, \mu)$ is $\sigma$-finite if X is a countable union of sets with finite measure.
My two questions is that
Does $\sigma$-finiteness imply that $\mu(E)<\infty$ for all $E \in \Sigma$?
If $\mu(E)<\infty$ for all $E \in \Sigma$, dose it imply $\sigma$-finiteness or finiteness of a measure space?
Thanks.
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